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Crime lab equipment, products and supplies for fingerprinting, crime scene investigation, property/evidence room, and narcotics identification. The Safariland Group

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(3) The Home Scientist 018 - Forensic Presumptive Drug Testing I - YouTube

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(3) The Home Scientist 018 - Forensic Presumptive Drug Testing I - YouTube

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The Home Scientist 018 - Forensic Presumptive Drug Testing I

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Maybe you found a paper in which they used gas chromatography (GC) to analyze a sample that is similar to yours and now you are wondering if you should try it too. If you are hesitant because you know little about GC, then this article will help you with that.

You may already know that chromatography covers a wide range of analytical techniques that are used to separate, identify, and quantify compounds. If you are familiar with other chromatography methods, such as HPLC or GPC, then you already know more than you think!

When it comes to GC, the compounds that are analyzed are in, not surprisingly, the gas phase. This doesn't mean that your sample has to be a gas (although it could). Instead, the gas chromatograph will vaporize it for you. After this, your material of interest will take a steamy journey through a column, where it is partitioned between a mobile phase and a stationary phase. The nature of this partitioning will dictate how much time a specific compound spends in the column until it eventually reaches the detector. This measure of time is called retention time (tR) and is determined by the detector when a compound exits the column. Figure 1 shows the basic components that make up a GC system.

How GC Works

Because the injector port is contained in an oven (see Figure 1), once you inject your sample it will be immediately vaporized (poof!). The gaseous molecules are then mixed with the mobile phase, which is also known as the carrier gas, because it does exactly that: it carries the sample through the column.

If you inject a mixture, the components will separate as they travel at different speeds. This happens because a compound can be either moving along with the carrier gas or spend some time attached to the stationary phase. The time that a compound spends interacting with the stationary phase will depend on the compound's unique composition. Therefore, it is expected that a sample containing multiple substances will result in different retention times (each substance with its own tR).

To put into context, you can imagine that a compound that is "held up" by the stationary phase will have a longer tR than another that is traveling freely with the mobile phase. It is because of this principle that GC has its usefulness.

GC Components: A Closer Look

Sample Injection

The type of sample can vary greatly depending on the study. Typically, GC samples consist of non-polar, low molecular weight, thermally stable, and vaporizable chemical material. It may be a single substance or a mixture, liquid or solid that is dissolved in solvent and only a tiny amount (few microliters) is injected via syringe. It is also possible to analyze gas samples (air, breath) and injection is usually through a gas valve.

Column/Stationary Phase

This is where all the action (a.k.a separation of compounds) takes place. The column is a coiled tube made of metal or glass material that can withstand high temperatures and vary in length or diameter. Inside of the tube is the stationary phase. This can be a number of different materials with varying polarities, either solid or liquid that interact with the chemicals passing through. The stationary phase is assembled as a compacted material (packed column) or as a wall-coating film (capillary column).

Mobile Phase

The carrier gas is introduced from a gas cylinder into the gas chromatograph. It moves through the column at a constant flow rate and exits at the detector outlet. Unlike other methods, the mobile phase in GC does not interact with chemicals and only serves to carry them. Because of this, the carrier gas must be inert. Some examples are helium, nitrogen, and argon. The type of detector on the GC usually determines which gas is used. It is not something that you would have to decide since a working GC should already have a gas tank connected to it.

Oven

Like any other oven, a GC oven provides heat. But instead of baking goods, what this oven gives you is vaporized material right after injection. In addition, it keeps the column heated so that you continue to have gaseous molecules traveling through. Its temperature could vary from room temperature to 300 °C, though the limits vary by instrument. A temperature program can be set electronically to maintain a constant temperature or to gradually increase (ramping). The program that you select will depend on the nature of the sample.

Detector

This is a device at the end of the column that senses each compound as it comes out. The data recorded by the detector is transmitted into a computer and produces a two-dimensional plot, called chromatogram. There are several types of detectors with varying detection methods and limits. A particular powerful detector is the mass spectrometer (MS). A GC coupled with an MS, known as a GC/MS system, produces a mass spectrum in addition to the chromatogram.

Reading the Chromatogram

A GC chromatogram (Figure 2) is a visual output of the data recorded by the detector. It is presented as a plot of detector response ( y-axis) versus retention time ( x-axis).

The chromatogram can tell you a number of different things. I will break it down into three main categories:

The nature of the sample. To evaluate the complexity of your sample you can count the number of peaks. Each compound detected by GC will appear as a single peak positioned at a specific tR. If you injected a mixture and the chromatogram shows three peaks, then this tells you that the sample had three different compounds. Now let's say that you wanted to confirm the purity of a sample. In this case you expect a single peak, and hopefully that's what you get!

The identity of the sample. A substance can be characterized by matching its tR with a literature value or by injecting reference material. The catch with this is that you have to use the same conditions for each case. This is important because the tR depends on many factors other than compound identity, such as gas flow, temperature, and column length. The GC/MS systems are the most powerful for compound characterization as they enable identification by mass.

The amount of sample. The peak area is proportional to the concentration of a substance in the original sample. Modern GC software will integrate the peak area and provide this information to you. The relative amounts of compounds in a sample can be determined by comparing the peak areas, or you can calculate the actual concentrations by using a standard calibration curve.

GC can be an intimidating technique at first but after giving it a couple of tries you will get the hang of it in no time! I would recommend watching this video for a visual tutorial on GC and reviewing this article for detailed information. Good luck!

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Maybe you found a paper in which they used gas chromatography (GC) to analyze a sample that is similar to yours and now you are wondering if you should try it too. If you are hesitant because you know little about GC, then this article will help you with that.

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1.06 Crime Scene Sketch GOALS FOR THIS LESSON - ppt download

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1.06 Crime Scene Sketch GOALS FOR THIS LESSON - ppt download

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1.06 crime scene sketch goals for this lesson

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1.06 Crime Scene Sketch GOALS FOR THIS LESSON - ppt download

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Why do we need a sketch with photos and videos? Crime scenes have to be documented with notes, photographs, and sketches Investigators take notes on observations, initial impressions, details of the scene, witness statements Photographers take photos of the evidence using different angles, ranges, overall scene, and different lighting.

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Reforming Forensics: Why Academics Are Challenging the Science Behind U.S. Criminal Justice | Discover Magazine

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Reforming Forensics: Why Academics Are Challenging the Science Behind U.S. Criminal Justice | Discover Magazine

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Reforming Forensics: Why Academics Are Challenging the Science Behind U.S. Criminal Justice

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Academics are fighting to reform criminal justice techniques — many of which are based on thin and outdated science — that have incriminated hundreds of innocent people in the U.S.

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Careers in Forensic Science - Careers in Forensics

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Careers in Forensic Science - Careers in Forensics

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Careers in Forensic Science - Careers in Forensics

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Must-have resources for understanding the requirements, responsibilities, roles and specializations of careers in forensic science.

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Murder Is Her Hobby: Frances Glessner Lee and The Nutshell Studies of Unexplained Death | Smithsonian American Art Museum

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Murder Is Her Hobby: Frances Glessner Lee and The Nutshell Studies of Unexplained Death | Smithsonian American Art Museum

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Lee, the first female police captain in the U.S., is considered the "mother of forensic science" and helped to found the first-of-its kind Department of Legal Medicine at Harvard University when the field of forensics was in its infancy. At the time, there was very little training for investigators, meaning that they often overlooked or mishandled key evidence, or irrevocably tampered with crime scenes. Few had any medical training that would allow them to determine cause of death. As Lee and her colleagues at Harvard worked to change this, tools were needed to help trainees scientifically approach their search for truth. Lee was a talented artist as well as criminologist, and used the craft of miniature-making that she had learned as a young girl to solve this problem. She constructed the Nutshells beginning in the 1940s to teach investigators to properly canvass a crime scene to effectively uncover and understand evidence. The equivalent to "virtual reality" in their time, her masterfully crafted dioramas feature handmade objects to render scenes with exacting accuracy and meticulous detail.

Every element of the dioramas-from the angle of miniscule bullet holes, the placement of latches on widows, the patterns of blood splatters, and the discoloration of painstakingly painted miniature corpses-challenges trainees' powers of observation and deduction. The Nutshells are so effective that they are still used in training seminars today at the Office of the Chief Medical Examiner in Baltimore.

Showcasing the Nutshells at the Renwick allows visitors to appreciate them as works of art and material culture in addition to understanding their importance as forensic tools, and to see Lee's genius for telling complex stories through the expressive potential of simple materials. While the Nutshells represent composites of real and extremely challenging cases featuring homicides, suicides, and accidental deaths, Lee imagined and designed each setting herself. She was both exacting and highly creative in her pursuit of detail-knitting tiny stocking by hand with straight pins, hand-rolling tiny tobacco-filled cigarettes and burning the ends, writing tiny letters with a single-hair paintbrush, and creating working locks for windows and doors.

The exhibition also highlights the subtly subversive quality of Lee's work, especially the way her dioramas challenge the association of femininity with domestic bliss and upend the expected uses for miniature making, sewing, an other crafts considered to be "women's work." Also evident is her purposeful focus on society's "invisible victims," whose cases she championed. Lee was devoted to the search for truth and justice for everyone, and she often featured victims such as women, the poor, and and people living on the fringes of society, whose cases might be overlooked or tainted with prejudice on the part of the investigator. She wanted trainees to recognize and overcome any unconscious biases and to treat each case with rigor, regardless of the victim.

As the Nutshells are still active training tools, the solutions to each remain secret. However, the crime scene "reports" (written by Lee to accompany each case) given to forensic trainees are presented alongside each diorama to encourage visitors to approach the Nutshells the way an investigator would.

Murder Is Her Hobby: Frances Glessner Lee and The Nutshell Studies of Unexplained Death is the first public display of the complete series of nineteen studies still known to exist. For the first time since 1966, 18 pieces on loan to the museum from the Harvard Medical School via the Maryland Office of the Chief Medical Examiner, will be reunited with the "lost nutshell," on loan from the Society for the Protection of New Hampshire Forests, courtesy of the Bethlehem Heritage Society. The exhibition is organized by Nora Atkinson, The Lloyd Herman Curator of Craft.

Lee's hyperreal constructions inspired contemporary artist and scenic designer Rick Araluce, whose immersive, large-scale installation is presented in the adjoining gallery. Rick Aracluce: The Final Stop opens concurrently with Murder Is Her Hobby: Frances Glessner Lee and The Nutshell Studies of Unexplained Death on October 20th.

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Murder Is Her Hobby: Frances Glessner Lee and The Nutshell Studies of Unexplained Death

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Lee, the first female police captain in the U.S., is considered the "mother of forensic science" and helped to found the first-of-its kind Department of Legal Medicine at Harvard University when the field of forensics was in its infancy.

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BVDA - BVDA: Materials and equipment for crime scene officers and forensic laboratories

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BVDA - BVDA: Materials and equipment for crime scene officers and forensic laboratories

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The First Criminal Trial That Used Fingerprints as Evidence | History | Smithsonian Magazine

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The First Criminal Trial That Used Fingerprints as Evidence | History | Smithsonian Magazine

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Just after 2 a.m. on the night of September 19, 1910, Clarence Hiller woke to the screams of his wife and daughter in their home at 1837 West 104th Street in Chicago. After a spate of robberies, residents of this South Side neighborhood were already on edge. Hiller, a railroad clerk, raced to confront the intruder. In the ensuing scuffle, the two men fell down the staircase. His daughter, Clarice, later recalled hearing three shots, followed by her mother screaming upstairs. Neighbors came running but the man had fled the home, leaving a dying Hiller by his front door.

The unknown assailant didn't make it far. Thomas Jennings - an African-American man who had been paroled six weeks earlier - was stopped a half-mile away wearing a torn and bloodied coat and carrying a revolver. But it was what he left behind that would be the focal point of his trial-a fingerprint from a freshly painted railing that he used to hoist himself through a window at the Hiller house. Police photographed and cut off the railing itself, claiming it would prove the identity of the burglar. In the eyes of the court, they were right; Hiller's murder would lead to the first conviction using fingerprint evidence in a criminal trial in the United States. At times controversial, this method of solving cases endures more than a century later.

Not only has fingerprinting had staying power in the legal system, the underlying method is fundamentally the same as when it was first introduced to American police departments. Prints are still evaluated based on the same descriptions of arches, loops and whorls written by Sir Francis Galton in the late 19th century. Further, the basic technique of collecting and comparing remains remarkably similar to what was applied to that rudimentary set of prints discovered at the Hiller home.

Jennings' defense attorneys raised questions about this new-and little understood-technique, as well as whether such evidence could even be legally introduced in court (the first time it was used in Britain, they claimed, a special law was needed to make such evidence legal). The defense team even solicited prints from the public in an effort to find a match and disprove the theory that fingerprints were never repeated. A courtroom demonstration, however, backfired badly: Defense attorney W.G Anderson's print was clearly visible after he challenged experts to lift the impression from a piece of paper that he had touched.

This made a distinct impression on the jury as well; they voted unanimously to convict Jennings, who was sentenced to hang. The Decatur Herald called it "the first conviction on finger-printing evidence in the history of this country," adding with dramatic flourish that "the murderer of Hiller wrote his signature when he rested his hand upon the freshly painted railing at the Hiller home."

It's unclear the degree to which Jennings's race played a part in his trial. News reports at the time didn't sensationalize race in their coverage, or even mention Hiller's race. Yet it's not hard to envision that a jury, presented with an unfamiliar technique, would have been more skeptical with a white defendant.

The concept of identifying people by unique fingerprints, first laid out 18 years earlier in Europe, even had its origin in pseudoscientific racial beliefs. It was thoroughly studied and chronicled in Galton's 1892 epic tome Finger Prints (A cousin of Darwin, Galton had long focused on a series of experiments hoping to tie myriad personal and intellectual characteristics to physical traits and heredity). Galton, who had also studied anthropometry in an effort to deduce the meaning behind physical measurements, did not find any major difference between races in his exhaustive collection of prints for research-but not for lack of effort. He wrote in Finger Prints that "it seemed reasonable to expect to find racial differences in finger marks, the inquiries were continued in varied ways until hard fact had made hope no longer justifiable."

As journalist Ava Kofman recently outlined in the Public Domain Review, Galton's pursuit of fingerprint science meshed well with colonialist ideology of the time. "Fingerprints were originally introduced for Europeans to distinguish between the otherwise indistinguishable mass of extra-European peoples, who themselves produced "indecipherable" fingerprints," she wrote. Later in his career, according to Kofman, Galton would later engage in quantifying racial differences, inventing "scientific," numerical measurements to categorize humans by race.

Nonetheless the system Galton outlined was to identify unique characteristics proved effective and caught on quickly. Police in the United States were just beginning to emulate their European colleagues and started to gather prints for the purpose of identification in the early 20th century. During the 1904 World's Fair in St. Louis, Scotland Yard sent representatives to host an exhibit to demonstrate the technique, which was growing in popularity in British courts. Even Mark Twain was caught up in the speculation of how they could be used to apprehend criminals, placing "the assassin's natal autograph" - which is to say the "blood-stained finger-prints" found on a knife- at the center of the dramatic courtroom finale in his novel Puddn'head Wilson, published years before the Jennings case.

After Jennings' conviction, however, lawyers mounted a challenge to the notion that such a newfangled and little-understood technique could be admitted in court. After more than a year in the appeals process, on December 21, 1911, the Illinois Supreme Court upheld the conviction in the People v. Jennings, affirming his sentence would be carried out soon after. They cited prior cases in Britain and published studies on the subject to lend credibility to fingerprinting. Several witnesses in the Jennings trial, it pointed out, had been trained by the venerable Scotland Yard. "This method of identification is in such general and common use that the courts cannot refuse to take judicial cognizance of it," the ruling stated.

Fingerprinting had thereby been "proclaimed by the Supreme Court of Illinois to be sufficient basis for a verdict of death by hanging," the Chicago Tribune reported, and it was the beginning of a shift toward the largely unquestioned use of fingerprint evidence in courtrooms across the United States. "The Jennings case really is the earliest case - earliest published case - in which you'll find any discussion of fingerprint evidence," says Simon A. Cole, author of Suspect Identities: A History of Fingerprinting and Criminal Identification and professor of criminology, law and society at the University of California, Irvine School of Social Ecology. "So, in that sense it really is a precedent for the whole country."

People v. Jennings further specified that fingerprint evidence was something that the average juror would have to rely on interpretation to understand. "Expert testimony is admissible when the subject matter of the inquiry is of such a character that only persons of skill and experience are capable of forming a correct judgment as to any facts connected therewith." The inclusion of this statement was crucial in legal terms: some level of human judgment and interpretation was a given, built into the courtroom process when fingerprint evidence was presented to a jury. The degree of subjectivity that represents and what potential room for error - however small - is acceptable is still actively debated more than a century later.

Beginning with the Jennings trial, two fundamental questions have formed the basis of any challenge to its admissibility in court. Is the technique itself sound (the primary issue when it was first introduced)? And how accurate the evidence is when interpreted and applied to any specific case? "The uniqueness of fingerprints is really kind of beside the point of the accuracy of the identification," says Cole. "The best way to understand that is to think about eyewitness identification - nobody disputes that all human faces are in some sense unique, even those of identical twins, but nobody reasons from that that eyewitness identification must be 100 percent accurate." Juries like the one that convicted Jennings were initially focused on whether prints were repeated, "whereas really what we need to know is can people match them accurately."

It is this gray area that defense attorneys seize on in thorny legal cases. Following a 1993 Supreme Court ruling in Daubert vs. Merrell Dow Pharmaceuticals Inc., judges were required to apply what is known as the Daubert standard to determine if a witness' testimony can be considered scientific. This is based on a list of factors, including how the technique itself has been tested, error rates and what regulations govern its usage. These standards were more stringent than what had previously been required, putting the onus on judges to determine what could be considered by a jury as scientific evidence.

Fingerprinting techniques came under marked public scrutiny in 2004 when an Oregon lawyer named Brandon Mayfield was arrested in connection with a terrorist attack on a commuter train in Madrid based on a mistaken match of a partial print gathered at the scene . The FBI later publicly apologized to Mayfield, but such high-profile incidents inevitably introduce questions about if other mistakes have gone unnoticed and fuel skeptics and lawyers who contest the often presumed infallibility of such evidence.

As part of a broader re-examination of forensics that had come to be widely accepted over the years, the National Academy of Sciences released a report in 2009 that addressed some of these shortcomings, acknowledging that "not all fingerprint evidence is equally good, because the true value of the evidence is determined by the quality of the latent fingerprint image. These disparities between and within the forensic science disciplines highlight a major problem in the forensic science community: The simple reality is that the interpretation of forensic evidence is not always based on scientific studies to determine its validity."

Fingerprint examiners rely on years of experience, testing and verification by a second examiner to bolster the reliability of their determination. Echoing the reasoning in the People v. Jennings ruling, fingerprint examiner William Leo writes that "the purpose of the expert witness in the legal system is to interpret information and form a conclusion that a jury of lay persons would be incapable of doing...A fingerprint examiner's conclusion is not based upon a personal opinion, but rather on an evaluation of the detail present using the knowledge and skills acquired through training, education and expertise."

"You'll probably find for the most part that most people are in agreement that most of the time if you have a decent print of some size that is of decent quality, you can make an identification in some reasonable percentage of cases," says David A. Harris, professor of law at the University of Pittsburgh and author of Failed Evidence: Why Law Enforcement Resists Science. "Where things have begun to come into question in the last 20 years is the way that those identifications have been done, the certainty with which they have been presented, the terminology around that and just a general harder look at all the forensic sciences."

When it comes to fingerprint evidence, uncertainty has not been eliminated, but is now more likely to be acknowledged and addressed. And despite greater skepticism in recent decades and the more stringent caveats introduced by Daubert, courts have not significantly curtailed the use of fingerprint evidence, nor the reliance on examiners to interpret this evidence for the jury.

"A hundred years is kind of an impressive run," says Cole. "There are some reasons for that - I think the fingerprint patterns are very information rich, you can see that there's a lot of information packed into a small area." When Thomas Jennings placed his hand on a porch railing in the middle of the night, he unwittingly introduced that valuable information into American courtrooms, influencing the outcome of innumerable cases for more than a century and counting.

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The First Criminal Trial That Used Fingerprints as Evidence

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Just after 2 a.m. on the night of September 19, 1910, Clarence Hiller woke to the screams of his wife and daughter in their home at 1837 West 104th Street in Chicago. After a spate of robberies, residents of this South Side neighborhood were already on edge.

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Ninhydrin: Basic to Advanced – Iowa Division of the International Association for Identification

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Ninhydrin: Basic to Advanced – Iowa Division of the International Association for Identification

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Pat A. Wertheim, Director of Training
Forensic Identification Training Seminars, Ltd.
1230 Hoyt St. S.E.
Salem, OR 97302-2121
1-888-235-1230

ABSTRACT: Ninhydrin, an amino acid reagent, may be applied to porous surfaces in a variety of solutions to develop latent finger and palm prints. The choice of application depends on the surface being processed, the expertise of the examiner, and the equipment and supplies available. Several chemical formulas are discussed, along with methods of application. Choosing the correct formula and method in any given situation will maximize the chances of success while minimizing the hazards, both to the examiner and the evidence.

GENERAL CONSIDERATIONS

Ninhydrin (synonym: 1,2,3-triketo-hydrindene hydrate) has been recognized since around the turn of the century as a reagent for detecting amino acids. However, it was not until the mid 1950's that it was discovered ninhydrin could be used to develop latent prints on porous surfaces. When ninhydrin comes into contact withamino acids in fingerprint residue, the reaction yields a red to purple print.

While effective on virtually any porous surface, ninhydrin is most appropriate for paper. On wood, silver nitrate may yield prints with darker ridges and better contrast because sometimes faint purple ridges of a ninhydrin print may get obscured by the wood grain and brown background color. This discussion, therefore, will address the use of ninhydrin on paper.

Several variables come into play. First, the types of amino acids and their concentration in the print determine whether a reaction will occur. Second, the reaction is most effective in an acidic environment but many white papers have calcium carbonate fillers or whiteners. Such fillers result in a basic environment tin the paper unless a mild acid is added to the ninhydrin reagent. Third, temperature and humidity influence the development of prints. Fourth, the strength of the ninhydrin and the type of carrier affect the reaction. With all of these variables, the development time and the darkness of the print may differ widely from case to case. it is always suggested that sample prints be placed on paper similar to that of the evidence processed as a control using the ninhydrin solution before actual evidence items are processed. Once the efficacy of the reagent solution has been established, the examiner may proceed with the evidence itself. Experience has shown that occasionally a latent print may only appear after several applications of ninhydrin.

If more than one method of chemical processing is to be used, the methods must be used in the correct order to avoid ruining the chances of subsequent success. On paper, the various methods should be used in the following sequence: 1) iodine fuming, 2) DFO (followed by florescence examination,) 3) ninhydrin, and 4) silver nitrate or physical developer. Not all methods may be advisable in all cases. Depending on the priority of the case and the resources available, an examiner may choose to use only one or two of these methods. But anytime a combination is chosen, the methods should be used in the correct sequence.

In many cases where fingerprints would be important, handwriting is also present on the paper. It should be recognized that any liquid soaking into the paper will alter the indentations left by the writing instrument. In addition, most chemicals used to dissolve ninhydrin also dissolve inks to some degree. Therefore, document examination should always precede fingerprint examination.

SAFETY CONCERNS

Many of the solvents used for ninhydrin are toxic and flammable, while even dry ninhydrin itself is harmful. Therefore, adequate safety precautions must be taken. Nitrile gloves should be worn rather than latex, as latex is soluble in many of the reagents but nitrile is resistant to chemicals. Goggles and a breathing mask should also be used. A lab coat should be worn o protect clothing. For safety reason, dipping the item into the solution or painting the solution onto the item with a cotton ball are preferable to spraying the solution onto the paper. because many of the solvents used are flammable, adequate ventilation should always be used and it should be ascertained that no source of flame or spark is present which might ignite fumes. A vent hood is recommended to remove fumes from the lab, both to remove any chance of explosion, and because many of the solvents and the ninhydrin itself may be hazardous.

PREMIXED SPRAYS

Several premixed sprays are available, including both aerosol cans and pump sprayers. Premixed sprays may be the most convenient way to purchase ninhydrin. However, it is much less expensive to mix your own solutions. And while all of these premixed sprays work well when "fresh," their shelf life is measured in months, not years. Because the age of a container may not be known when purchased, and the conditions of storage and shipment are variable, there may be little uniformity from can to can. In addition, contamination may occasionally render a can of premixed spray not only ineffective, but damaging to the item being sprayed. Finally, spraying is no longer recommended as a method of application because of the excessive amount of both ninhydrin and carrier introduced into the air. Even when working under a vent hood, airborne droplets of solution may find their way back into the laboratory atmosphere.

MIXING YOUR OWN SOLUTIONS

While mixing your own solutions may not be quite as easy as using a spray can off the shelf, it is significantly less expensive and generally more effective for developing latent prints. A number of different solutions may be prepared, depending on the specific application involved and your comfort in mixing chemicals. Different solutions have different characteristics, as well as different advantages and disadvantages.

Solutions may be mixed ahead and stored for later use, or a small amount may be mixed sufficient only for the application at hand. Some solutions may require a "stock solution" and a "working solution." In those, a concentrated solution is prepared (the stock solution) and mixed with a carrier prior to use (the working solution.) You may select as simple or sophisticated a solution as you are comfortable with, and either mix it ahead or for each use separately. Since it is up to you, the examiner, to determine what is most appropriate and defend your choice in court, it is important that you be familiar with different methods and make an informed decision on which one to use. Two ninhydrin solutions are presented here for your consideration, one simple to prepare, the other slightly more sophisticated.

SIMPLE SOLUTION: NINHYDRIN IN ACETONE (or methanol, or ethanol)

The simplest solution to prepare is made by using a 25 gram jar of ninhydrin powder or crystals. Obtain a gallon (4 liters will do) can or jar of acetone from a paint store or chemical supply house. Pour the entire jar of ninhydrin powder into the gallon container and stir until completely dissolved. The solution is ready for use and should last a month or two if kept out of light and away from heat.

Because of shelf life concerns, unless you use a large amount of ninhydrin, it is not recommended you mix it all at once. Instead, by using approximately the proportions given above, smaller amounts of solution may be prepared. For example, for a single use amount for a forged check. a few spoons of acetone may be used, and a "pinch" of ninhydrin stirred in until dissolved. WARNING: Acetone dissolves most inks, and the writing on the check, threatening letter, or drug ledger may be completely washed out using this simple method.

based on availability, methanol (methyl alcohol) or ethanol (ethyl alcohol may be preferred to acetone. Alcohols evaporate more slowly than acetone, and therefore the paper takes longer to dry. Also, the alcohols do not have as strong an odor os acetone, and one is less apt to be aware of breathing hazardous fumes. Like acetone, alcohols dissolve ink. Acetone and alcohols are flammable, so care must be exercised in keeping these solutions away from any source of ignition.

BETTER SOLUTION: NINHYDRIN IN HEPTANE

With the banning of freon, it is no longer possible to use of the most popular and effective solutions for ninhydrin. An alternate carrier has been sought for several years. The Police Scientific Development Branch of the Home Office, UK, recently found a suitable replacement formula using heptane. Their formula for ninhydrin in heptane is as follows:

Ninhydrin....................................5 grams
Ethanol.....................................75 milliliters
Ethyl Acetate...............................25 milliliters
Acetic Acid..................................3 milliliters
Heptane......................................1 liter

First, dissolve the ninhydrin in the ethanol, ethyl acetate, and acetic acid. Then add the heptane. The solution has a shelf life of several months. Heptane is flammable, so care must be exercised in keeping the solution and fumes away from any source of ignition. This solution results in only minimal running of ink and is very effective at developing latent prints. In fact, efficacy studies at the Home Office indicate this formula may even be more effective than the old freon formula.

CONCLUSION

When fingerprinting paper items, freshly mixed solutions are generally more dependable than premixed chemicals. if a document examination is appropriate, it should be done before fingerprint chemicals are applied. If more than one technique is to be tried, such as iodine or silver nitrate, the various techniques must be done in the correct sequence. From a safety standpoint, dipping the item in a tray of ninhydrin solution or painting the ninhydrin onto the surface with a cotton ball are preferable to spraying. Acetone or alcohol solutions are more likely to damage inks than a heptane formula. Nitrile gloves, a lab coat, safety goggles, and breathing mask should be worn at all times when working with ninhydrin powder or solutions.

Pat A. Wertheim

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Iowa Division of the International Association for Identification

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Pat A. Wertheim, Director of Training Forensic Identification Training Seminars, Ltd. 1230 Hoyt St. S.E. Salem, OR 97302-2121 1-888-235-1230 ABSTRACT: Ninhydrin, an amino acid reagent, may be applied to porous surfaces in a variety of solutions to develop latent finger and palm prints.

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More Info What is prescription pain reliever misuse? As defined by the National Survey on Drug Use and Health, it's "use without a prescription of one's own or use at a higher dosage or more often than prescribed." Prescription opioid addiction - stemming from misuse - has hit the nation hard in recent years.

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20 Virtual Labs & Activities for Forensic Science ⋆ The Trendy Science Teacher

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20 Virtual Labs & Activities for Forensic Science ⋆ The Trendy Science Teacher

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As a new school year approaches, Forensics teachers across the world are scrambling to find virtual labs and activities for their Forensic Science classrooms. In my collaborative Facebook group for Forensic Science teachers, the question " How do we virtually teach such a hands-on course?" comes up in conversation on a weekly basis. (If you are a Forensic science teacher that is looking to collaborate with other FS teachers, we invite you to join us. Click HERE to join the group!) It is for that reason that I decided to put together a resource for all of my Forensics teacher friends- 20 Virtual Labs & Activities for Forensic Science. Let's get started!

#1: Virtual Microscope Lab

First up in my list of 20 Virtual Labs & Activities for Forensic Science is a virtual microscope lab. One of the first concepts that I teach in Forensics is the microscope. This interactive site features a virtual step-by-step guide to viewing a specimen under the microscope. After having my students visit the interactive site, I have them complete the virtual microscope lab. This year, I will be having my students complete this digital document as they maneuver through the two labs.

#2: Observation Skills & Crime Scene Investigation Interactivity

In this interactivity, students make observations from the dioramas of true crime scenes known as The Nutshell Studies of Unexplained Death. These dioramas were constructed in the 1940s by Frances Glessner Lee as a way to teach crime scene investigators how to properly investigate crime scenes. To introduce observation skills and crime scene investigation, I have my forensics students complete this web-quest and interactivity over Lee's Nutshell Studies. This interactive tour and web-quest will provide your students with practice in making observations and inferences and really sets the foundation for the rest of the course.

#3: Disease Detectives (Deductive Reasoning) Digital Lesson

This next lesson is extremely applicable to what we are experiencing in the world with regards to Covid-19 and can be used to bridge epidemiology with detective work and deductive reasoning skills. This lesson uses a real-life case to demonstrate how epidemiologists and other public health workers respond when there is a suspected outbreak-or sudden increase in the number of cases-of a disease. It shows the importance in using scientific evidence to derive a conclusion. The entire lesson and supporting documents can be found here.

#4: Virtual Crime Scene

One of my favorite parts of teaching forensics is creating mock crime scenes for my students. Although this year's crime scenes may look a little different, there is no reason why we can't still offer our students digital mock crime scenes that allow them to showcase their skills. In this digital crime scene, students will make observations, collect evidence, and use their deductive reasoning skills to solve the crime. Here is the the supporting document that I created for my students.

#5: Virtual Crime Lab Tour

This YouTube video is a great way to show students what goes on inside of a real-life crime lab. I plan on having my students watch this tour and answer these guided video questions.

#6: Fingerprint Case Study-Digital Assignment

My students always love discussing the Richard Ramirez (The Night Stalker) case and I knew that I wanted to incorporate it into my virtual classroom this fall when we discuss fingerprinting. With the help of one of my Forensics Teachers Facebook Group members, I have a digital case study ready to go. Click here to grab the digital assignment.

#7: Fire Lab- Virtual Arson Investigation

Next up in my list of 20 Virtual Labs & Activities for Forensic Science is one of my favorites- an interactive site that walks students through the science behind how fires burn. Then, they are able to gather evidence from a virtual arson investigation and analyze their collections to solve the crime. This entire virtual activity can serve as both the lesson and the practice, making it great for online or flipped classrooms. It's also perfect for both high school and middle school students! Want a free resource download that accompanies this website? Click to download the packet that I provide for my students.

#8: Arson Investigation Podcast

I love a good podcast and this one doesn't disappoint. It is appropriate for both the middle and high school classroom and takes students through a 13- episode journey through the events surrounding an arson investigation. Don't worry about creating a supporting document for this podcast! I've got you covered. Click HERE to get the resource that I use with my own students as we listen to this intriguing podcast mystery.

#9: Forensic Toxicology-WebQuest & Lab

My students always enjoyed this activity when we were face-face for instruction. Therefore, I am definitely adding it to my virtual lessons when we get to our toxicology unit. This interactive website showcases the life of a forensic toxicologist and has students solve a crime using lab tests and data analysis. There is a great supporting document that compliments this activity (thanks again to another wonderful Forensic Teacher Tribe Facebook Group member).

#10: Virtual Autopsy

We are half-way through our list of 20 Virtual Labs & Activities for Forensic Science and I can't wait to share the next resources!

I have used this virtual autopsy as practice for my infamous PIG AUTOPSY project for several years. However, this past year, I wasn't able to conduct the anticipated pig autopsy with my students (cue the tears). As a replacement, I did assign this virtual autopsy activity. Although it didn't bring the same WOW factor as the pig autopsy, it was a good virtual replacement when I needed it.

#11: DNA Fingerprinting Virtual Lab

In this DNA Fingerprinting virtual lab, students get a first hand experience creating a DNA profile using electrophoresis. I have used this online lab for years and will definitely be adding it to my virtual lessons this year!

#12: Entomology Digital Investigation

This digital entomology investigation was created by one of our Forensic Facebook Group members. In this activity, students examine insects found at a crime scene to estimate the post mortem interval of a victim whose body is found in a wooded area.

#13: Online Ballistics Simulation

I just recently happened upon this ballistics simulation and I have mixed emotions about it. The idea of it is great and if you need a digital ballistics activity, this is a good option (if you can get past the typos and a few glitches here and there). This simulation begins with an informative page and has students take a pre-test before moving in to a mock crime scene. Once presented with the scene, students collect and analyze ballistic evidence to solve the case.

#14: Blood Typing Virtual Lab

Coming in at #14 in our list of 20 Virtual Labs & Activities for Forensic Science is a blood typing lab simulation. In this blood typing online lab simulation, a doctor has a patient that needs a blood transfusion and there are three potential donors . Students use their knowledge of blood types to determine which donor can donate blood to the doctor's patient. One of our FB group members created a complimentary resource that can be found HERE.

#15: Gel Electrophoresis Interactive Activity

Gel electrophoresis labs can be costly! If you're on a shoe-string budget, consider assigning this electrophoresis interactive activity to your students.

#16: Glass Analysis- Interactive (for Google Classroom)

One of the sweet members of our Facebook group, Forensic Science Teacher Tribe, shared this next resource with our members. This Google Slides activity is perfect for those teachers that are using Google Classroom this year. This activity walks students through the process of glass analysis and provides students with instruction, but in an interactive way. You can check out the resource here.

#17: Decomposition & Entomology Virtual Lab

One of my favorite activities to use in my Entomology Unit is my Maggot Man lab! Although my students are often hesitant of it, they love it. Unfortunately, it's difficult to observe the decomposition process as it pertains to blow-fly activity in a virtual setting, so I was happy to find this alternative to one of my students' favorite labs.

This HHMI web-based activity uses video and an online portal to walk students through the stages of decomp and insect activity. The online activity can be found , teacher instructions can be found , and the supporting document for this activity can be found .

#18: Drug Interactions-Online Simulation

I have used the Mouse Party online simulation for many years during my toxicology unit. This interactive activity from the University of Utah provides students with the opportunity to digitally investigate how different kinds of drugs alter the natural state of a mouse's brain. To find supporting documents for this online simulation, click here.

#19: Handwriting- Digital Investigation

In this digital Handwriting Investigation, students take on the role of a QD examiner to determine if a document has been forged. This activity would be great to use both digitally and in face-to-face instruction for a quick and easy practice for handwriting analysis.

#20: Digital Mock Crime Scene

Last up on my list of 20 Virtual Labs and Activities for Forensic Science is this Digital Mock Crime Scene- The Case of the Barefoot Burglar. If you ask any of my previous Forensics students what their favorite part of the class was, they will tell you THE MOCK CRIME SCENES. With social distancing guidelines in place, it is making it difficult for in-person teachers to conduct mock crime scenes. Additionally, online teachers are wondering how mock crime scenes can be done online. I am excited to have found this digital option to offer my students. Check it out here.

Well...that's it! I hope that you have found this post to be super-helpful in easing your mind about this CRAZY school year. I'd love to hear more suggestions from you guys. If you have an online or digital lab that you LOVE, drop a comment below!

As always, HAPPY TEACHING!

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20 Virtual Labs & Activities for Forensic Science ⋆ The Trendy Science Teacher

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In this post, I will share 20 virtual labs & activities that you can use to teach Forensic Science, whether it be in-person or online.

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Guide for Casting Footwear and Tire Impression Evidence

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Guide for Casting Footwear and Tire Impression Evidence

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by

1. Scope

1.1 This Guide provides procedures that should be used for the casting of footwear and tire impression evidence.

1.2 The particular procedures and methods employed in a given case will depend on the evidence.

1.3 This Guide may not cover all aspects of unusual or uncommon conditions.

1.4 This Guide does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this Guide to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1.5 This Guide is not intended as a substitute for training in the casting

of footwear and tire impression evidence. Completion of a training program and experience in these skills is essential to understanding and applying the principles outlined in this Guide. 1.6 This Guide relates to the casting of footwear and tire impressions as part of the collection of impression evidence for examination in the laboratory.

2. Terminology

3. Significance and Use

3.1 The procedures outlined here are grounded in the generally accepted body of knowledge and experience in the casting of footwear and tire impression evidence. By following these procedures, impressions can be properly cast.

3.2 Footwear and tire impressions are cast for the purpose of collecting impression evidence for subsequent examination in the laboratory.

4. Interferences

4.1 Footwear and tire impression evidence may have inherent limitations that can interfere with the procedures in this Guide. Limitations, when known, should be noted and recorded.

4.2 Limitations can be due to substrate features, environmental conditions, quality and quantity of original impressions, casting techniques and casting materials.

5. Equipment and Requirements

5.1 Casting materials (i.e., dental stone and sulfur)

5.2 Zip-lock bags and mixing containers

5.3 Water

5.4 Measuring cups

5.5 Sufficient time to complete all applicable procedures

5.6 Stirring spoon or stick

5.7 Stove or hot plate for melting sulfur

5.8 Potassium Sulfate

5.9 Snow Print Wax™

5.10 Grey primer or aerosol paint

5.11 Release agents and fixatives (i.e., hairspray or similar sprays)

5.12 Scale for weighing casting materials

6. Procedures

6.1 The following procedures may be used as appropriate depending on the composition of the impression evidence and the substrate material. The order of the following collection methods may vary from scene to scene.

6.2 Document and/or photograph (as set forth in theGuide for the Forensic Documentation and Photography of Footwear and Tire impressions at the Crime Scene) impressions prior to any procedure.

6.3 Casting impressions with dental stone in soil and sand

6.3.1 If necessary, prepare impressions for casting.

6.3.1.1 When casting a fragile impression, it may be necessary to apply a fixative. Care should be exercised when applying fixatives to minimize any possibility of damage to the impression.

6.3.1.2 When casting in dense soils, it may be necessary to apply a release agent. Care should be exercised when applying release agents to minimize any possibility of damage to the impression.

6.3.2 Add appropriate amount of water to a pre-measured amount of dental stone. The average footwear impression requires approximately two (2) pounds of dental stone and approximately ten (10) ounces of water. The amount of water required may vary depending on the casting product. The resulting mixture should have the viscosity of heavy cream. The viscosity of the mixture may need to be adjusted based upon the nature of the impression.

6.3.3 Mix continuously for a minimum of 3-5 minutes so that the powder can thoroughly absorb the water.

6.3.4 Pour casting material carefully outside the perimeter of the impression and direct the flow into the impression. Ensure the impression is completely filled and/or covered evenly. In the event that the casting material does not flow completely into the impression, the top surface of the casting material can be agitated to help it flow. Casts should be of sufficient thickness to avoid breakage. If necessary, additional casting material may be poured over the top of the original cast to complete the cast and/or add thickness.

6.3.4.1 For fragile and shallow impressions, pour casting material from outside the perimeter so that it rapidly flows over the impression. A thinner mixture of casting material is necessary for this technique. Avoid pouring directly onto the uncovered impression.

6.3.4.2 Larger quantities of dental stone can be mixed in a bucket to cast large segments of tire impressions. 36 segments are optimal for examination. Shorter segments may also be of value.

6.3.4.3 Impressions underwater may be cast using dental stone and specialized techniques.

6.4 Casting impressions with dental stone and sulfur in snow

6.4.1 If necessary prepare impressions for casting. It is noted that snow varies considerably in texture and type. Application of highlighting materials (such as Snow Print Wax™ or aerosol paints) may be advantageous during photography. These materials may or may not be necessary for the casting process.

6.4.1.1 A thin application of highlighting spray may be directed at the impression from an oblique angle to increase the contrast of the detail. The application of highlighting sprays to the snow impression may increase melting, therefore the impression may need to be shielded from the sun until it can be photographed and cast.

6.4.1.2 A thick application of Snow Print Wax™ may then be applied to create a shell for the dental stone casting material.

6.4.2 Casting with dental stone

6.4.2.1 Add a heaping tablespoon of Potassium Sulfate to the pre-weighed bag of dental stone.

6.4.2.2 Add snow to the water source and place the bags of dental stone in the snow to pre-cool the ingredients.

6.4.2.3 Add the appropriate amount of water to the pre- measured dental stone. A thicker mixture should be used for snow.

6.4.2.4 Pour the casting material from outside the perimeter and direct the flow into the impression. The surface of the casting material can be agitated to help it flow.

6.4.3 Casting with sulfur

Caution: This technique requires that the user be familiar with safety issues regarding the use of sulfur. Manufacturer's safety information and warnings should be consulted before using this material.

6.4.3.1 Melt the sulfur and cool to an opaque, partially crystallized state before pouring into the impression.

6.4.3.2 Pour from the perimeter, allowing the melted sulfur to flow into the impression.

6.4.3.3 Due to the extremely brittle nature of sulfur casts, dental stone may be poured over the back of the cooled sulfur cast to reinforce it prior to lifting.

6.5 Marking and handling the cast impressions

6.5.1 Casts should be marked prior to removal. Markings should include identifier numbers which link the casts to diagrams and/or photographs; date and initials; and any other pertinent information such as case number.

6.5.2 Allow casting material to thoroughly harden prior to removal.

6.5.3 Carefully remove cast impression from substrate. It may be necessary to excavate the cast to avoid breakage.

6.5.4 Allow dental stone casts to thoroughly dry for 48 hours prior to any attempts to clean the cast.

6.5.5 Casts must be thoroughly dry before storage or packaging.

6.5.6 Casts should be adequately packaged to avoid breakage during storage or shipping.

6.6 Cleaning dental stone casts

6.6.1 When possible, casts should be cleaned in the laboratory by the examiner.

6.6.2 If necessary, prior to cleaning, preserve any soil or other evidence attached to the cast.

6.6.3 Soil and sand can be cleaned from casts using water and a soft brush.

7. Report

7.1 Procedures utilized and evidence collected should be documented and may also appear in a report.

8. Bibliography

Bodziak, W. J., Footwear Impression Evidence, 2nd ed.; CRC Press: Boca Raton, FL, 2000.

Bodziak, W. J., Hammer, L., "An Evaluation of Dental Stone, Traxtone, and Crime Cast", JFI, 56 (5), 2006 769-787.

Cassidy, M. J., Footwear Identification; Public Relations Branch of the Royal Canadian Mounted Police: 1980. (Reprinted by Lightning Powder Company, Inc. 1995)

Hammer, L., Wolfe, J., "Shoe and Tire Impressions in Snow: Photography and Casting", JFI, 53 (6), 2003.

Hueske, Edward E., "Photographing and Casting Footwear/Tiretrack Impressions in Snow", JFI, 41 (2), 1991.

IAI Recommended Course of Study for Footwear & Tire Track Examiners, International Association for Identification: Mendota Heights, MN, 2006.

Nause, L., Forensic Tire Impression Identification, Canadian Police Research Centre: Ottawa, ON, Canada, 2001.

Nause, L., "Casting Footwear Impressions in Snow: Snowprint-Wax vs. Prill Sulphur", RCMP Gazette, Vol. 54, No. 12, 1992.

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Guide for Casting Footwear and Tire Impression Evidence

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by 1. Scope 1.1 This Guide provides procedures that should be used for the casting of footwear and tire impression evidence. 1.2 The particular procedures and methods employed in a given case will depend on the evidence. 1.3 This Guide may not cover all aspects of unusual or uncommon conditions.

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Reliable Consistency and Dependable Performance Type III, Buff, Blue, Pink

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Fire and Arson Investigations | National Institute of Justice

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Fire and Arson Investigations | National Institute of Justice

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Fire and arson investigators examine the physical attributes of a fire scene and identify and collect physical evidence from the scene. This evidence is then analyzed to help determine if the cause of the fire was accidental or deliberate. During the scene examination, investigators may find evidence such as accelerants, tampered utilities, and specific burn patterns, which may indicate criminal activity.

NIJ addresses the specific needs of the fire and arson investigation community by funding research to develop new and improved tools and techniques to interpret, identify and analyze evidence at fire scenes.

NIJ funds research to:

Better understand fire dynamics.

Improve ways to detect, analyze and identify accelerants, such as gasoline.

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Fire and arson investigators examine the physical attributes of a fire scene and identify and collect physical evidence from the scene. This evidence is then analyzed to help determine if the cause of the fire was accidental or deliberate. During the scene examination, investigators may find evidence such as accelerants, tampered utilities, and specific burn patterns, which may indicate criminal activity.

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Fire and Arson Scene Evidence: A Guide for Public Safety Personnel (Research Report)

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Fire and Arson Scene Evidence: A Guide for Public Safety Personnel (Research Report)

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This course examines the psychology of eyewitnesses and its impact on police investigations- revealing the limitations of the human mind and the dangers for criminal justice. Witnesses often only identify somebody about 40% of the time from a line up. Sometimes the suspect that's been identified isn't actually the culprit. The journey begins by exploring some serious miscarriages of justice. Featuring a real eyewitness whose testimony sent the wrong man to prison. I knew there had been misidentification- I mean I knew that. It wasn't malicious intent, it wasn't racially motivated- but it didn't matter, because the end result was Ronald Cotton spent a third of his life in prison for something he didn't do.

The course also gives you a chance to follow two investigations of a fictitious crime. And use your cognitive and investigative skills to evaluate the evidence. The course was created by professor Graham Pike, who specialises in eyewitness identification, including E-Fit technology. There are new generation of facial composting systems that are beginning to be used by the police. Graham Pike was also behind a BBC Open University co-production, which is incorporated into the course, and which puts eyewitnesses to the test. By working solely from eyewitness accounts and positive identifications, how close to the truth have they got? Giving you the chance to use what you have learned to solve a crime and compare how you did against a team of real police officers.

By completing the eight week course, you will have gained some basic knowledge about forensic psychology, gained insights into how your own mind works, and understood the vital role of psychology in police investigations.

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This course examines the psychology of eyewitnesses and its impact on police investigations- revealing the limitations of the human mind and the dangers for criminal justice. Witnesses often only identify somebody about 40% of the time from a line up. Sometimes the suspect that's been identified isn't actually the culprit.

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Chemistry and Crime
Narcotics and Test Reagent Kits.

Cannabis useage across the world, 2012

An interactive map showing major drug use by region, 2012.
Sources: United Nations Office on Drugs and Crime (UNODC), Annual Reports Questionnaire Data/DELTA and National Government Reports

TheWorld Customs Organisation (WCO) Illicit Trade Reports now cover drugs and tobacco etc. The latest, generally published in June, (2013 report) is available. Initially these analysed seizures on a regional basis and by category of drug intercepted, and focussed in particular on routings, means of transport and concealment methods used. Emphasis was placed on the illegal trade in opiates, cocaine, cannabis, and psychotropic substances. The 2009 figures showed that there were 14,127 seizures of drugs, yielding a total of 533 tonnes of narcotics, including 43 tonnes of cocaine, 408 tonnes of cannabis and 21 tonnes of opiates. The number of seizures in 2009 remained relatively stable compared with 2008, although there was a decrease in the quantities of drugs intercepted (533 cf. 600 tonnes).

Regional Intelligence Liaison Offices (RILO)

2007

2008

2009

2011

2012

Grand Total 13,367 14,255 14,127 47,156 43,385

Globally, the United Nations Office on Drugs and Crime (UNODC) estimated that, in 2009, between 149 and 272 million people, or 3.3% to 6.1% of the population aged 15-64, used illicit substances at least once in the previous year. About half that number were estimated to have been current drug users, that is, having used illicit drugs at least once during the past month prior to the date of assessment. While the total number of illicit drug users has increased since the late 1990s, the prevalence rates have remained largely stable, as has the number of problem drug users*, which is estimated at between 15 and 39 million.

*While there is no established definition of problem drug users, they are usually defined as those who regularly use illicit substances and can be considered dependent, and those who inject drugs.

Cannabis is by far the most widely used illicit drug type, consumed by between 125 and 203 million people worldwide in 2009. This corresponds to an annual prevalence rate of 2.8%-4.5%. In terms of annual prevalence, cannabis is followed by ATS (amphetamine-type stimulants; mainly methamphetamine, amphetamine and ecstasy), opioids (including opium, heroin and prescription opioids) and cocaine. Lack of information regarding use of illicit drugs - particularly ATS - in populous countries such as China and India, as well as in emerging regions of consumption such as Africa, generate uncertainty when estimating the global number of users. This was reflected in the wide ranges of the estimates.

While there are stable or downward trends for heroin and cocaine use in major regions of consumption, this is being offset by increases in the use of synthetic and prescription drugs. Non-medical use of prescription drugs is reportedly a growing health problem in a number of developed and developing countries.

Narcotic Reagent Kits
Identification of narcotics or other controlled substances can be a difficult task. There are many potential methods and formulae, that all require knowledge of chemistry and laboratory techniques. For quick presumptive testing, colour spot tests for identification purposes are typically used, and these are generally completed outside of a laboratory.

The kits are designed so that there is no need for measurement of chemicals or special equipment. In each plastic tube are crushable glass ampoules with the complete chemistry for each test. The specified amount of suspect material is added and the test is then performed according to the instructions. A typical set of reagent test kits are shown below:

Colour coded results for narcotic tests

--TEST--

REAGENT

SUBSTANCE PRESUMPTIVELY IDENTIFIED

No. 1

Mayer's Reagent

Alkaloids, Amphetamines

No. 15

Methamphetamine,
Simon's and Robadope's Reagent

Methamphetamine, MDMA (Ecstasy)

Mayer's Reagent
A precipitating reagent for alkaloids prepared from a solution of mercuric chloride and potassium iodide in deionized water.

Alkaloid + K₂[HgI₄] ↔ [Alkaloid-H⁺][HgI₃]⁻ ↓ (or [HgI₄]) salt
The formation of a creamy-white precipitate is indicative of the presence of one of the narcotic alkaloids or the amphetamines.

This is often the first screening test performed and depending on the result may lead to further testing with Marquis' Reagent or the Dille-Koppanyi Reagent.

Marquis' Reagent
The Marquis reagent is a spot test for alkaloids that was first reported in 1896. The original testing agent was a mixture of 2 drops of 40% formaldehyde and 3 milliliters of concentrated sulfuric acid. It was originally used for detecting small amounts of certain alkaloids, and for distinguishing between them. The signature of the alkaloid is both the initial colour produced, as well as the sequence of colour changes occurring with time. In the early days the Marquis reagent was used primarily to distinguish the opium alkaloids. Each alkaloid had a pattern of colour change.

The colour reaction of morphine with Marquis' Reagent results in a purple to violet colouring. It is proposed that two molecules of morphine and two molecules of formaldehyde condense in the presence of conc. sulfuric acid to the dimeric product which is protonated to the oxoniumcarbenlum salt.

Cobalt Thiocyanate Reagent, Scott's test
Cobalt thiocyanate in aqueous solution and stannous chloride in aqueous solution.
Various field tests are used to identify cocaine/crack in apprehended street samples. Most of them are based on complexation of the alkaloid with cobalt(II) thiocyanate (Co(SCN)₂(H₂O)₄) solution which results in the formation of a blue colour. The cobalt thiocyanate test was developed in 1973 and later improved to make it applicable to crack.
A recent article highlighted the use of TLC for detection of cocaine and suggested the blue colour is a 6 coordinate Co(II) species with one isothiocyanate ligand a bidentate cocaine molecule and 3 waters coordinated?

Scott's Reagent

See as well a study on the variation of acids used for acidifying the solution and the effect of temperature on the test.

A suggested reaction is the change from octahedral pink Co(II) to tetrahedral blue Co(II) similar to that seen for the chloride salts.

[Co(SCN)(H₂O)₅]⁺(aq) + 3 SCN⁻(aq) + 2 R₃NH⁺ ↔ (R₃NH)₂[Co(SCN)₄] + 5 H₂O(l)
where [R₃NH]⁺ represents the protonated cocaine ion.

At 4°C the sensitivity of the test was found to double compared to room temperature (22°C), while temperatures in excess of 40°C decreased the sensitivity of the test more than twofold versus room temperature. These findings clearly show the impact that storage, use, and interpretation of commercially available cocaine test kits in typical field settings may experience in very hot ambient temperatures.

Dille-Koppanyi Reagent
The original 2 part test was developed in the 1930s by American pharmacologists Theodore Koppanyi and James M. Dille as a simple spot-test to presumptively identify barbiturates.

Part A is 0.1 g of cobalt(II) acetate dihydrate dissolved in 100 ml of methanol mixed with 0.2 ml of glacial acetic acid. Part B is made up of 5% isopropylamine (v/v) in methanol. Two drops of A are addeded to the substance followed by one drop of B and any colour changes observed.

The test turns phenobarbital, pentobarbital, amobarbital and secobarbital light purple.

N-non-substituted barbiturates can be detected with Dille-Koppanyi's Reagent. Isopropylamine is responsible for the deprotonation of the barbiturate molecule. The purple colour is caused by complex formation between two barbiturate molecules, two isopropylamine molecules around a tetrahedral cobalt(II). The isopropylamines are thought to act as stabilizers of the complex.

Mandelin Reagent
The Mandelin reagent is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. It is prepared by the addition of 100 mL of concentrated (95-98%) sulfuric acid to 1 g of ammonium vanadate.

According to the Journal of the American Pharmaceutical Association Volume 19, Issue 12, pages 1292-1299, December 1930

"An ammonium vanadate-sulfuric acid solution, as a test for strychnine was first proposed by Mandelin in 1883. A few alkaloids besides strychnine will give colour reactions with this reagent. According to Witthaus the following alkaloids give strychnine-like reactions with this reagent:
1. Curarin gives about the same play of colours, but the appearance is very much delayed. Curarin, however, is not extracted with organic solvents in alkaline solutions.
2. Gelsemin produces a purple or red-violet colour.

In 1915, it was shown that yohimbine, an alkaloid obtained from the bark ofCorynanthe Johimbe, gives the same purple with Mandelin's reagent as strychnine. However upon dilution with water the purple colour developed by strychnine changes to a beautiful rose-pink colouration, whereas with yohimbine no such colour develops upon dilution.

In 1889, a number of alkaloids were tested with Mandelin's reagent. Distinctive colours with twenty-three of the common alkaloids were obtained. Apart from strychnine, violet or violet-blue colours were obtained with apomorphine and papaverin."

Ehrlich's Reagent
A solution of p-dimethylamino benzaldehyde and concentrated hydrochloric acid.

The colouring matter produced is determined by the concentration of the acid, the solvents and other conditions of the reaction. After the condensation of one molecule of LSD with one molecule of p-dimethylamino benzaldehyde, the carbinole is formed. After protonation water is eliminated to form the carbenium ion, which then reacts by the addition of a second molecule of LSD. This is finally oxidized to the blue-coloured cyanine.

Duquenois-Levine Reagent
The test was initially developed in the 1930s by Pierre Duquenois, and was adopted in the 1950s by the United Nations as the preferred test for cannabis, and originally claimed to be specific to cannabis.

The reagent can be prepared by adding 2 grams of vanillin and 2.5 milliliters of acetaldehyde to 100 milliliters of ethanol.

The Duguenois-Levine Test describes the determination of cannabis resin by forming the violet-coloured product above, which can be extracted with chloroform.
It is now recognised that it is NOT specific however, despite this, it maybe the only test performed on substances and be used as evidence for conviction.

KN (Fast Blue B Salt) Reagent
KN= Kanto-Shin'etsu Narcotics Control Office, Japan
Presumptive test designed to identify the presence of THC in Marijuana, Hashish or Hash Oil. It is also designed to react with the green leaf material of fresh Marijuana. Upon breakage of the 2nd ampoule, a layering will occur and the lower layer must be a Tomato Red colour for a positive test.

The Reagent contains a solution of naphthanil diazo blue B in chloroform and a solution of aqueous sodium hydroxide.

Valium Reagent - Zimmerman Test
A solution of potassium hydroxide in methanol and a solution of m-dinitrobenzene in isopropanol.

Diazepam, more commonly known by its trade name, Valium, is a benzodiazepine and a controlled substance (Schedule IV in the United States and under International Control as well). It is a potent sedative - hypnotic (CNS depressant), and is one of the most prescribed drugs in the world. It is one of the top five most abused benzodiazepines, and misuse can lead to both psychological dependence and/or physical addiction.

The State of California offers diazepam to condemned inmates as a pre-execution sedative as part of their Lethal Injection program.

Drug-facilitated sexual assault - Date-rape drugs
Flunitrazepam Rohypnol, Rufinol or Roofies are known to induce anterograde amnesia in sufficient doses; individuals are unable to remember certain events that they experienced while under the influence of the drug. This effect is particularly dangerous when flunitrazepam is used to aid in the commission of sexual assault; victims may be unable to clearly recall the assault, the assailant, or the events surrounding the assault.

Rohypnol is manufactured by Hoffman-La Roche. It is sold in tablet form in clear bubble packaging, with the tablets inscribed on one side with the word "Roche." It has no taste or smell. Originally the tablets were manufactured only in white and, if dissolved in liquid, did not affect its colour. But once it became known that Rohypnol was being used to facilitate rape, Hoffman-La Roche began manufacturing an additional version coated in a hard green shell to inhibit dissolution, and containing a strong blue dye.

It is difficult to estimate just how many flunitrazepam-facilitated rapes have occurred.

Zimmerman's test for Benzodiazepines

Methamphetamine, Simon's and Robadope's Reagent
Simon's reagent is composed of an aqueous mixture of sodium nitroprusside, sodium carbonate and acetaldehyde, which is dripped onto the substance being tested. The amine and acetaldehyde produce the enamine, which subsequently reacts with sodium nitroprusside to the imine. Finally, the immonium salt is hydrolysed to the bright cobalt-blue Simon-Awe complex.
Robadope reagent can be used for detecting primary amines.
Acetaldehyde can be replaced with acetone, in which case the reagent detects primary amines instead, giving a purple coloured product.

Note the paper for identification of methamphetamines using FTIR that was recently published in PLoS ONE:
Hughes J, Ayoko G, Collett S, Golding G (2013) Rapid Quantification of Methamphetamine: Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Chemometrics. PLoS ONE 8(7): e69609. doi:10.1371/journal.pone.0069609

Mecke's Modified Reagent
The Mecke reagent is used as a simple spot-test to presumptively identify alkaloids as well as other compounds. The reagent which is prepared by the addition of 100 mL of concentrated sulfuric acid to 1 g of selenious acid is dripped onto the substance being tested.

The blue to green colour produced by Mecke's Reagent with morphine is thought to arise from the initial rearrangement to apomorphine, which in the presence of selenious acid is oxidized to the o-quinone of apomorphine.

Frohdes Talwin Reagent
Frohdes Reagent - Presumptive test designed to identify the presence ofPentazocine which is a synthetically prepared prototypical mixed narcotic (opioid analgesic) drug of the benzomorphan class of opioids used to treat moderate to moderately severe pain. It may exist as one of two enantiomers, (+)-pentazocine and (-)-pentazocine. (-)-pentazocine is a κ opioid receptor agonist, while (+)-pentazocine is not.

After the discovery of its misuse, naloxone was added to oral preparations containing pentazocine to prevent the opioid reaction.

Upon breakage of the 2nd ampoule and after shaking, a bright blue appears in the presence of Pentazocine.
The Reagent is prepared from 1 g of sodium molybdate in 100 mL of concentrated H₂SO₄.

Ephedrine Reagent
An aqueous solution of sodium carbonate and sodium nitroferricyanide and a solution of m-dinitrobenzene in isopropanol.

Chen-Kao Test
Detection of ephedrine by its reaction with copper sulfate and sodium hydroxide, was first noted by Nagai (1892): a purple color appears, which is extractible with ether. This test is sensitive to one part of ephedrine in 400, and if the concentration exceeds 1 in 40 a pinkish purple precipitate is formed, and this is completely soluble in ether.
The formation of a violet-coloured chelate complex with copper sulfate in alkaline medium is considered to be characteristic "selective" for phenylalkylamines with vicinal amino- and hydroxyl-groups and has been in use in pharmaceutical analysis for the simple identification of ephedrine, pseudoephedrine, norephedrine and norpseudoephedrine.
The result of the Chen-Kao reaction is a symmetrical chelate complex. The colour, solubility and the stability of this complex appears to be affected by the structural and steric differences of the alkylamine. Tests on a range of ephedrine-type compounds showed that only ephedrine and pseudoephedrine gave the typical violet solution. Other derivatives produced a blue precipitate.

Cu(ephedrine) ₂ complex, Bull. Chem. Soc., Jpn., (1964), 37, 1363,

Special Opiates
A solution of sulfuric acid and selenious acid.

PCP Reagent
An aqueous solution of cobalt thiocyanate and concentrated phosphoric acid.

References
UWI students can see OurVLE for copies of some of the reports mentioned above.

Kovar, Karl-Artur and Martina Laudszun. Chemistry and Reaction Mechanisms of Rapid Tests for Drugs of Abuse and Precursors Chemicals, United Nations Scientific and Technical Notes v.89-51669, Germany. February 1989.

National Institute of Justice. Colour Test Reagents/Kits for Preliminary Identification of Drugs of Abuse, NIJ Standard 0604.01, National Law Enforcement and Corrections Technology Center, Rockville, MD. July 2000.

United Nations Office On Drugs and Crime (UNODC), Laboratory and forensic science services

SCIENTIFIC AND TECHNICAL NOTES SCITEC/20 December 2005 Colour Tests for Precursor Chemicals of Amphetamine-Type Substances

United Nations International Drug Control Programme. Rapid Testing Methods of Drugs of Abuse, UN standard ST/ NAR/13/RE V.1, United Nations, New York, NY. 1994.

Continue toGC-IRMS or return to CHEM2402 course outline.

This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Return to Chemistry, UWI-Mona, Home Page
Created and maintained by Prof. Robert J. Lancashire,
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica

URL http://wwwchem.uwimona.edu.jm/courses/CHEM2402/Crime/Reagent_KitsJS.html

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Narcotics and Test Reagent Kits. Cannabis useage across the world, 2012 An interactive map showing major drug use by region, 2012. Sources: United Nations Office on Drugs and Crime (UNODC), Annual Reports Questionnaire Data/DELTA and National Government Reports TheWorld Customs Organisation (WCO) Illicit Trade Reports now cover drugs and tobacco etc.

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How do claims and evidence support the process of forensics in fire investigation? There's been a fire. Your students' job will be to solve the case, to figure out where the fire started (point of origin) and how (cause)? To do this, your students must learn the basic science of fire -- how it behaves and the evidence it leaves left behind, and then apply that knowledge to solve the case.

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How do claims and evidence support the process of forensics in fire investigation? There's been a fire. Your students' job will be to solve the case, to figure out where the fire started (point of origin) and how (cause)?

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1) Explain what an STR sequence is
2) Understand how STRs can be used to create a DNA profile
3) Demonstrate the probability of a random DNA match.

4) Discuss the FBI CODIS System
Motivation:

How could we determine the probability that two individuals in the class are related using DNA? This is infinitely more complicated. Although there are only 30 people in the room, DNA is an extremely large molecule (each chromosome contains 50 million to 250 million base pairs -- and we have 46 chromosomes!). Forensic scientists make the job a bit simpler by limiting the comparison to sections of 13 different chromosomes...
What is the probability a student in the class is wearing a blue shirt today? Start by counting the number of people in the room. What are the possible number of colors they could have worn? This is a large number. We could make it simpler by limiting the options to primary colors: Red, Green and Blue. Each individual has a 1 in 3 chance of wearing blue. If there are 30 students in the room, then the probability of a student wearing blue is 1/3 x 30 = 1/10.

http://www.biology.arizona.edu/human_Bio/activities/blackett2/str_description.html
"Most of our DNA is identical to DNA of others. However, there are inherited regions of our DNA that can vary from person to person. Variations in DNA sequence between individuals are termed "polymorphisms". As we will discover in this activity, sequences with the highest degree of polymorphism are very useful for DNA analysis in forensics cases and paternity testing. This activity is based on analyzing the inheritance of a class of DNA polymorphisms known as "Short Tandem Repeats", or simply STRs.

"STRs are short sequences of DNA, normally of length 2-5 base pairs, that are repeated numerous times in a head-tail manner, i.e. the 16 bp sequence of "gatagatagatagata" would represent 4 head-tail copies of the tetramer "gata". The polymorphisms in STRs are due to the different number of copies of the repeat element that can occur in a population of individuals.

"D7S280 is one of the 13 core CODIS* STR genetic loci. This DNA is found on human chromosome 7. The DNA sequence of a representative allele of this locus is shown below. This sequence comes from , a public DNA database. The tetrameric (4-base) repeat sequence of D7S280 is "gata". Different alleles of this locus have from 6 to 15 tandem repeats of the "gata" sequence. How many tetrameric repeats are present in the DNA sequence shown below? (Answer: 12) Notice that one of the tetrameric sequences is "gaca", rather than "gata". 1 aatttttgta ttttttttag agacggggtt tcaccatgtt ggtcaggctg actatggagtGenBank

61 tattttaagg ttaatatata taaagggtat gatagaacac ttgtcatagt ttagaacgaa
121 ctaacgatag atagatagat agatagatag atagatagat agatagatag atagacagat
181 tgatagtttt tttttatctc actaaatagt ctatagtaaa catttaatta ccaatatttg
241 gtgcaattct gtcaatgagg ataaatgtgg aatcgttata attcttaaga atatatattc
301 cctctgagtt tttgatacct cagattttaa ggcc

* What is CODIS?
"The Federal Bureau of Investigation (FBI) of the US has been a leader in developing DNA typing technology for use in the identification of perpetrators of violent crime. In 1997, the FBI announced the selection of 13 STR loci to constitute the core of the United States national database, CODIS (Combined DNA Index System).

"There are many advantages to the CODIS STR system: The CODIS system has been widely adopted by forensic DNA analysts STR alleles can be rapidly determined using commercially available kits. STR alleles are discrete, and behave according to known principles of population genetics The data are digital, and therefore ideally suited for computer databases
1.
2.
3.
4.
5. Laboratories worldwide are contributing to the analysis of STR allele frequency in different human populations 6. STR profiles can be determined with very small amounts of DNA."

An STR profile of an individual is shown below. Note two peaks at most of the loci tested. (This STR profile exceeds the 13 recommended by the FBI and includes additional loci used by international law enforcement agencies.) The peaks indicate the individual has heterozygous alleles at a loci. (One peak = homozygous alleles.) Also, note that each allele has a boxed nymber below it; these are the number of short tandem repeats (for the base sequence GATA) at each loci.

How are STRs used to determine the probability of a DNA match?
"As part of his training and proficiency testing for DNA Profile analysis of STR (Short Tandem Repeat) Polymorphisms, Forensic Scientist and DNA Analyst Bob Blackett created a DNA profile on his own DNA. Here is Bob's DNA Profile for the 13 core Genetic Loci of the United States national database, CODIS (Combined DNA Index System):

"For each genetic locus, Bob has determined his "genotype", and the expected frequency of his genotype at each locus in a representative population sample. For example, at the genetic locus known as "D3S1358", Bob has the genotype of "15, 18". This genotype is shared by about 8.2% of the population. By combining the frequency information for all 13 CODIS loci, Bob can calculate that the frequency of his profile would be 1 in 7.7 quadrillion Caucasians (1 in 7.7 times 10 to the 15th power!)

"In Bob's forensic DNA work, he often compares the DNA profile of biological evidence from a crime scene with a known reference sample from a victim or suspect. If any two samples have matching genotypes at all 13 CODIS loci, it is a virtual certainty that the two DNA samples came from the same individual (or an identical twin)."

Activities: STR Interpretation Exercise (Paternity Case), and Random Match Probability Exercise

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1) Explain what an STR sequence is2) Understand how STRs can be used to create a DNA profile3) Demonstrate the probability of a random DNA match. 4) Discuss the FBI CODIS System Motivation: How could we determine the probability that two individuals in the class are related using DNA?

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The wildland arsonist: one of the most dangerous criminals - Wildfire Today

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The wildland arsonist: one of the most dangerous criminals - Wildfire Today

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The one criminal who possesses the power of a nuclear weapon at his fingertips is the wildland arsonist.In certain areas of the world, if the weather and fuel conditions are favorable, a wildland arsonist has the instant ability to burn an entire community to the ground, and kill scores of people, their pets, livestock, and the wildlife in the area.All of this carnage for the mere price of a match, a lighter or a road flare.

The good news is that there aren't that many people intentionally setting arson fires in the wildlands, as yearly statistics prove that the overwhelming number of wildfires are not acts of arson.The less good news is that historically, many of the actual wildland arson cases go "unsolved".The reasons for this are many, but one important reason is that compared to their urban counterparts, wildland arson investigators working for public agencies get very little money for resources and investigative training.Wildland arson cases have two distinct phases; the scene work, and then the follow-up criminal investigation.Many wildland investigators have a high degree of skill when conducting the "Origin and Cause" investigation at the scene, but they often lack the years of experience and ongoing certified training to pursue the criminal investigation portion of the case.There are currently very few schools, books, or online sources out there dedicated specifically toward conducting an arson investigation in the wildlands.

That's too bad.Analysis of case histories shows that a significant portion of wildland arsons are committed by a small number of persons...the serial arsonists.The majority of arson series are eventually solved, provided that the arsonist continues setting fires.It is not unusual for investigators to learn that a single serial arsonist in the wildlands had set twenty to one hundred fires (or more) prior to the arrest.
Threat Assessment
Traditionally, the fire service (urban and wildland) rates arson fires by their damage (dollar loss) or their size in acreage.This may greatly affect how much attention, manpower, and resources are devoted to an investigation.But, to an investigator, the size of the fire has very little to do with assessing the threat level of an arsonist, as the size of the fire event is completely out of the hands of the arsonist.The below factors are much more important to consider when conducting any threat assessment during a wildland arson investigation of an unknown subject.These factors are important when considering the intent of the arsonist.

-Large number (more than three) of suspicious or arson fires in an area
-Rapid frequency of suspicious or arson fires in an area
-Arson fires purposely set in extreme fire conditions
-The use of an incendiary device by the arsonist

If any of these four factors are present, then even small fires or failed arson events (all serial arson cases have these) are to be considered high threat.If an investigator determines that an offender is high threat, then the investigator must take immediate steps to approach this investigation as a major case investigation, and employ an arson task force approach to the case.

It is well known among modern criminal investigators that if you dedicate enough resources on any case, you can probably solve it fairly quickly.The real issue is that public agencies seldom have the luxury to focus on any one case until it gets media attention.This causes "small" fires set by arsonists to be classified as a "nuisance", and put on the back burner for weeks or months until the arsonist sets a much larger or more destructive fire.

Our position is that through training, and a proper threat assessment after every arson event, (small or large), investigators will more quickly focus resources on an emerging problem before the disastrous arson attack takes place.
Arson Task Force Approach and Investigative Mindset
This investigative mindset simply means treating the case as a major case from the beginning and using sufficient resources to solve the problem.A task force can be as few as three to four investigators, or up to hundreds of investigators and support personnel.The key to every task force is simple:Bring the right people to the team, not the most.

An arson task force should be comprised of veteran investigators who have the ability to think and to be flexible.It should be led by a law enforcement trained manager, who works alongside the Lead Arson Investigator.The Origin and Cause experts must be highly trained and certified in their skill, so that they can testify in court at a later date.All other task force officers should be experienced enough to conduct general investigative duties such as interviewing, and leads/canvassing operations.

Specialists to aid the task force should be considered.Specifically, crime analysts, cell phone and computer experts, social media investigators, man-trackers, scent tracking K-9's, CSI personnel, and experienced profilers are excellent additions to any arson task force.
Sensitive Information
All arson investigations, particularly major cases, are highly sensitive and should be treated with the utmost confidentiality.Only those persons actually on the investigative task force should know the details of the case and any evidence found.FBI and USFS studies of past major wildland cases show that the majority of investigations were plagued with information "leaking" that jeapordized the prosecution of the case.Case sensitive information and photos should never be shared via email, social media, or posted at fire or police stations.
Investigative Steps
Despite past beliefs, arson cases are not "special" and are quite similar to a typical homicide investigation.Done correctly, many of them are solvable .Arson investigators should conduct their investigations by mimicking the methodology used by successful homicide detectives.The following steps are recommended (in roughly this order) for most major criminal investigations, including arson:

-Scene Processing: Origin and Cause, and CSI work for criminal evidence
-Scene photography/video
-Interviews: Responding firefighters, 911 caller, citizen "rescuers", witnesses, etc
-Evidence Recovery: incendiary device, foot or tire impressions, physical evidence
-Evidence Exploitation: all evidence must get to a crime lab immediately for forensic exploitation
-Use of accelerant K-9s'; and use of Scent Tracking and Mantracking Teams
-Canvassing Operations
-Social Media Investigations
-Crime Analysis to look at historical fires in your area, or adjoining areas
-Plotting fire events on maps and charts (Geo-spatial and Temporal Analysis)
-Pattern Analysis: Experts brought in to analyze the case for patterns and linkage
-Behavior Analysis or Profiler: Useful on serial cases, or for analyzing incendiary devices
-Case building techniques: Linking a suspect or vehicle to the scene via forensics, eyewitnesses, etc; or linking one scene in a series to additional suspicious scenes
-Surveillance Operations
-Search warrants: For the suspect's home, work, vehicle, cell phone, computer, etc
-Arrest and Interview of suspect
-Court preparation
Incendiary Devices
It is not common to find incendiary devices in any arson event,However, the use of an incendiary device is more common in the wildland setting than any other type of arson (other than extremist arsons).An incendiary device is the single most important piece of evidence in any arson/serial arson case.The device should be treated like gold and should be immediately brought to a crime lab for forensic exploitation and analysis.

Device analysis will tell the investigator volumes about the unknown subject, as the use of incendiary or explosive devices is considered learned behavior.That means that the subject has some past experience or training in building, testing, and deploying devices.

Forensics recovered from an incendiary device can positively link the arsonist to a fire or a series of fires.
Help is Available
There are currently in the wildland arson investigation sector a few places where investigators can hone their skills and receive up-to-date training.The FI-210 Origin and Cause training offered by various entities is mandatory for any wildland investigator, but it is merely the first step.The FI-310 training program has undergone an update and is ready for new classes in the upcoming year. The Nevada chapter of the IAAI currently hosts annual training each February in Reno, Nevada, dedicated to Major Wildland and Serial investigations.The authors urge fire managers to invest early in training your investigators.
About the authors:
Joe Konefal is a retired Supervising Bomb Technician and Arson Investigator for the California Department of Forestry and Fire Protection.He has worked in the arson and bomb world for more than 35 years.He has been the Lead State of California instructor for arson-explosives related topics for two decades.

Ed Nordskog is a retired Arson-Bomb Investigator and Profiler for the Los Angeles (California) Sheriff's Department.He has been a Detective for most of his 35 year law enforcement career.He is an author of four previous books on arsonists, serial arsonists, and incendiary devices, and is an internationally known expert on these subjects.

Together, both Joe and Ed have worked nearly 3,000 cases in the arson world, including being involved in over 60 serial arson investigations, have a combined 30 years of teaching arson and related subjects to other investigators, and have testified over 150 times as "experts" on these subjects in court.

They are co-authors of the books and Arson Investigation in the Wildlands (available only at arsonwildlandsbook.com ) and Fire Death Scene Investigation.

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The wildland arsonist: one of the most dangerous criminals - Wildfire Today

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By Joe Konefal and Ed Nordskog The one criminal who possesses the power of a nuclear weapon at his fingertips is the wildland arsonist. In certain areas of the world, if the weather and fuel conditions are favorable, a wildland arsonist has the instant ability to burn an entire community to the ground, and kill ...

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Your Guide To Good — And Bad — TV Forensics : Short Wave : NPR

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Your Guide To Good — And Bad — TV Forensics : Short Wave : NPR

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subscribe to Short Wave podcast

subscribe to Short Wave podcast

Stevica Mrdja/EyeEm/Getty Images

Raychelle Burks is a forensic chemist AND a big fan of murder mysteries. Today, we talk pop culture forensics with Raychelle and what signs to look for to know whether or not a tv crime show is getting the science right.

Follow Maddie on Twitter @maddie_sofia. Email the show at shortwave@npr.org.
This episode was produced by Brit Hanson and edited by Viet Le.

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A Short Wave Guide To Good - And Bad - TV Forensics : Short Wave

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Raychelle Burks is a forensic chemist AND a big fan of murder mysteries. Today, we talk pop culture forensics with Raychelle and what signs to look for to know whether or not a tv crime show is getting the science right.Follow Maddie on Twitter @maddie_sofia. Email the show at shortwave@npr.org.

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Multimedia Resources from NIJ's Forensic DNA Training Courses | National Institute of Justice

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Multimedia Resources from NIJ's Forensic DNA Training Courses | National Institute of Justice

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May 2013

NIJ hosts free, self-paced online courses that include videos and animations developed with funding from NIJ. You are free and encouraged to use these as a resources in your own classrooms or other work. We ask only that you acknowledge NIJ as the source.

The videos and animations below are arranged by the course in which they appear.

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Multimedia Resources from NIJ's Forensic DNA Training Courses

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May 2013 NIJ hosts free, self-paced online courses that include videos and animations developed with funding from NIJ. You are free and encouraged to use these as a resources in your own classrooms or other work. We ask only that you acknowledge NIJ as the source.

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Parabon® Snapshot® DNA Analysis Service - Powered by Parabon NanoLabs

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Parabon® Snapshot® DNA Analysis Service - Powered by Parabon NanoLabs

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COOL What Genetic
Genealogy Is
Snapshot Genetic Genealogy

Genetic Genealogy (GG) is the combination of genetic analysis with traditional historical and genealogical research to study family history. For forensic investigations, it can be used to identify remains by tying the DNA to a family with a missing person or to point to the likely identity of a perpetrator.

By comparing a DNA sample to a database of DNA from volunteer participants, it is possible to determine whether there are any relatives of the DNA sample in the database and how closely related they are (see Snapshot Kinship Inference for more details). This information can then be cross-referenced with other data sources used in traditional genealogical research, such as census records, vital records, obituaries and newspaper archives.

Why Use Genetic Genealogy?

Genetic genealogy gives you a powerful new tool to generate leads on unknown subjects. When a genetic genealogy search yields useful related matches to an unknown DNA sample, it can narrow down a suspect list to a region, a family, or even an individual. Paired with Snapshot DNA Phenotyping to further reduce the list of possible matches, there is no more powerful identification method besides a direct DNA comparison. Identity can then be confirmed using traditionalSTR analysis.

How Does This Technique Differ From Familial Searches in the CODIS Database?

Our genetic genealogy service is somewhat like familial search, but it differs in three very important ways: (1) we only search public genetic genealogy databases, not government-owned criminal (STR profile) databases, such as CODIS; (2) because the DNA SNP profiles we generate contain vastly more information than traditional STR profiles, genetic relatedness can be detected at a far greater distance (see Snapshot Kinship Inference); and (3) because genetic genealogy matches can be cross-referenced by name with traditional genealogy sources, such as Ancestry.com, existing family trees can be used to expedite tree-building and case-solving. This technology and our innovative techniques combine to create a groundbreaking system for forensic human identification.
How Genetic
Genealogy Works
How Genetic Genealogy Works

Genetic genealogy uses autosomal DNA (atDNA) single nucleotide polymorphisms (SNPs) to determine how closely related two individuals are. Unlike other genetic markers, such as mitochondrial DNA or Y chromosome DNA, atDNA is inherited from all ancestral lines and passed on by both males and females and thus can be used to compare any two individuals, regardless of how they are related. However, atDNA SNPs are more difficult to obtain from forensic samples, which is why Parabon has created an optimized laboratory protocol to ensure high-quality results even from small, degraded DNA samples.

The standard atDNA metric used by genetic genealogists is the amount of DNA that two people are likely to have inherited from a recent common ancestor. This can be estimated by looking for long stretches of identical DNA. While alleles can easily be shared by chance at one or a few SNPs, it is highly unlikely for two unrelated people to share a long stretch of DNA. Therefore, only segments above a certain length are counted. The length of these shared segments is measured in centimorgans (cM), a measure of genetic distance, and the total number of cM shared across all chromosomes can be used to determine approximately how closely related two people are. The figure below shows how shared segments of DNA on a single chromosome are broken up with each generation, leading to shorter shared segments for more distant relatives. Using a public genetic genealogy database, DNA from an unknown person can be compared to roughly 1 million other people to see whether any of them are related.

DNA database matches serve as clues on which traditional genealogy methods can build, starting with building the matches' family trees using a wide variety of information sources. During the tree building process, the genetic genealogist searched for common ancestors who appear across multiple family trees of the matches. Ideally, marriages between the descendants of the identified common ancestors are discovered. Then descendancy research is employed to search for descendants at the intersection of these common ancestors who were born at a time that is consistent with the subject's estimated age range. The goal of this search is to narrow down the possible individuals to a set of names, a family, or even an individual.

Depending on the amount of information available from the matches, genetic genealogy can produce a wide range of leads. In all cases that proceed to analysis, genetic genealogy will significantly narrow the scope of possible identities for the person-of-interest. In some cases, the identity will be narrowed to descendants of a particular ancestor or from a particular region. In others, our analysts can produce the name and address of the person-of-interest. In all cases, identity must be confirmed through traditional forensic DNA matching.

Genetic Genealogy
Use Cases
Genetic Genealogy Use Cases

Genetic genealogy has traditionally been used to discover new relatives and build a full family tree. However, it can also be used to discover the identity of an unknown individual by using DNA to identify relatives and then using genealogy research to build family trees and deduce who the unknown individual could be. These techniques have primarily been used to discover the family history of adopted individuals, but they apply equally as well to forensic applications. Genetic genealogy has been used to identify victims' remains, as well as suspects, in a number of high-profile cases.

Because genetic genealogy uses the same type of data generated for Snapshot DNA Phenotyping and Snapshot Kinship, the analysis can quickly be performed on existing cases, and new cases have a wide array of options for generating new leads from a single DNA sample.
DNA
Phenotyping What DNA
Phenotyping Is
The Snapshot DNA Phenotyping Service

DNA Phenotyping is the prediction of physical appearance from DNA. It can be used to generate leads in cases where there are no suspects or database hits, to narrow suspect lists, and to help solve human remains cases.

DNA carries the genetic instruction set for an individual's physical characteristics, producing the wide range of appearances among people. By determining how genetic information translates into physical appearance, it is possible to "reverse-engineer" DNA into a physical profile. Snapshot reads tens of thousands of genetic variants ("genotypes") from a DNA sample and uses this information to predict what an unknown person looks like.

Over the past four years, using deep data mining and advanced machine learning algorithms in a specialized bioinformatics pipeline, Parabon - with funding support from the US Department of Defense (DoD) - developed the Snapshot Forensic DNA Phenotyping System, which accurately predicts genetic ancestry, eye color, hair color, skin color, freckling, and face shape in individuals from any ethnic background, even individuals with mixed ancestry.

Because some traits are partially determined by environmental factors and not DNA alone, Snapshot trait predictions are presented with a corresponding measure of confidence, which reflects the degree to which such factors influence each particular trait. Traits, such as eye color, that are highly heritable (i.e., are not greatly affected by environmental factors) are predicted with higher accuracy and confidence than those that have lower heritability; these differences are shown in the confidence metrics that accompany each Snapshot trait prediction.
How DNA
Phenotyping Works
How DNA Phenotyping Works

Whereas traditional DNA forensics matches STRs from a sample to a known suspect or a database, DNA phenotyping can generate new leads about an individual, even if they have not previously been identified in a database. DNA phenotyping takes advantage of modern SNP technology to read the parts of the genome that actually code for the differences between people.

The Snapshot DNA Phenotyping System translates SNP information from an unknown individual's DNA sample into predictions of ancestry and physical appearance traits, such as skin color, hair color, eye color, freckling, and even face morphology. Each phenotype prediction is made with a measure of confidence, including those that can be excluded with high confidence.

SNP Technology

Recent advances in genomic technology have made it practical and affordable to read the sequence of millions of pieces of DNA from a small quantity of sample. This data captures a large proportion of the genomic variation between people and thus contains much of the genetic blueprint that differentiates people's appearance. These SNP genotypes can then be paired with phenotypes from thousands of subjects to create a genotype-and-phenotype (GaP) dataset for analysis.

Data Mining

Beginning with large GaP datasets containing genetic information and measures of phenotype for thousands of subjects, Parabon's bioinformatics team performs large-scale statistical analysis on hundreds of thousands of individual SNPs and billions of SNP combinations to identify genetic markers that are associated with a trait. This mining process can take weeks of compute time running on hundreds, sometimes thousands, of computers. In the end, those SNPs with the greatest likelihood of contributing biologically to the trait's variation are selected for potential use in predictive models.

Data Modeling

In the modeling phase, Parabon's scientists use machine learning algorithms to combine the selected set of SNPs into a complex mathematical equation for the genetic architecture of the trait. A new, unknown individual's SNP data can then be plugged into this equation to produce a prediction of the trait in that individual.

Model accuracy is assessed by making predictions on new subjects with known phenotypes ("out-of-sample predictions"). By comparing predicted versus actual phenotypes, Parabon scientists are able to calculate confidence statements about new predictions and, more importantly, exclude highly unlikely traits. For example, if 99% of brown-eyed people have an eye color prediction value greater than 2, then we can have very high confidence that a prediction of 1.5 most likely did not come from a brown-eyed person.

The final models are calibrated with all available data before being installed into the Snapshot production service that is used to generate phenotype predictions for investigators.
DNA
Phenotyping
Success Stories
Snapshot Success Stories

Snapshot has been used by hundreds of law enforcement agencies around the world to help generate leads, narrow their suspect pools, and solve human remains cases, in both active and decades-old investigations.

Featured Case Summaries: Read detailed case descriptions, including how Snapshot helped solve the following cases:

On Wednesday 26 March 1986, Michella Welch, a petite 12-year old girl with long blond hair and glasses, went missing. She had taken her two younger sisters to Puget Park in Tacoma, Washington at about 10 a.m. and then rode her bicycle home about 11 a.m. to make lunch for them. When she returned, she chained her bike next to one of her sister's bikes, set the lunches on the table and went looking for her siblings, who had gone to a nearby business to use the restroom.

A 13-year-old classmate later told detectives he saw a man in the park that day under the Proctor Bridge who... More

Testimonials: To read about how Snapshot has helped our clients with their investigations, see:

https://snapshot.parabon-nanolabs.com/testimonials

Published Investigations: To learn how Snapshot is being used by additional law enforcement agencies - and to read about other solved cases - please visit the published police investigation page at:

https://snapshot.parabon-nanolabs.com/posters

Blind Evaluations: Snapshot was built by Parabon NanoLabs for the defense, security, justice, and intelligence communities with funding from the United States Defense Threat Reduction Agency. As part of the development and validation process, Snapshot was tested on thousands of out-of-sample genotypes and was shown to be extremely accurate.

To see examples of Snapshot predictions from blind evaluation studies, visit:

https://snapshot.parabon-nanolabs.com/examples

Example of How To Use Snapshot: To learn how you can use Snapshot to narrow a suspect pool, watch:

https://snapshot.parabon-nanolabs.com/nbc-news-video

Ancestry
Determination What Ancestry
Determination Is
Predicting Genetic Ancestry With Snapshot

Scientific analysis of human genomes from different parts of the world has shown that, on a global scale, modern humans divide genetically into seven continental populations: African, Middle Eastern, European, Central/South Asian, East Asian, Oceanian, and Native American1. These genetic divisions stem simply from the fact that these groups were isolated from one another for many generations, and thus each group has a unique genetic signature that can be used for identification. In order to determine a new subject's genetic ancestry, Parabon Snapshot analyzes tens of thousands of SNPs from a DNA sample to determine a person's percent membership in each of these global populations. Other forensic ancestry approaches assume that every individual comes from only a single population, so they can easily be confounded by admixed individuals, but Snapshot allows for contributions from multiple populations, so it can detect even low levels of admixture (<5%).

After global ancestry is determined, Snapshot's ancestry algorithm investigates which subpopulations (e.g., Northwest vs. Northeast Europe) an individual comes from. This analysis is robust to admixture, such that each piece of continental ancestry can be precisely localized within that continent. For example, the admixed East Asian and Latino example from the global map above was determined to have specifically Japanese, Central American, and Southwest European ancestry, as shown in the map below.

Using all of this information, Snapshot builds a precise profile of an individual's ethnic ancestry using only his or her DNA.
How Ancestry
Determination Works
How Genetic Ancestry Determination Works

Parabon has built a powerful system for determining ethnic ancestry from DNA. Most other forensic ancestry systems use only a small number of SNPs and thus are limited to very coarse populations and cannot detect admixture between populations. Snapshot uses tens of thousands of SNPs across the genome to obtain very precise estimates of ancestry, even for admixed individuals. Parabon's scientists have collected data from many published scientific articles, totalling more than 9,000 individuals with clearly defined ancestry from more than 150 populations around the world, as shown in the map below.

Academic research using hundreds of thousands of SNPs from across the genome has shown that human groups generally divide into seven continental populations, which have been established over the past 50,000 years during the migration out of Africa. The 150 populations collected as the ancestry background can thus be divided into these seven continental groups according to their origin.

Snapshot builds on this research by mapping a new person's genome onto these established populations. Our algorithm calculates how similar the new individual's DNA is to each of the background populations, determining which population(s) the person comes from. This allows for contributions from multiple groups, so even small amounts of admixture (<5%) can be detected.

Snapshot takes a similar approach to identifying within-continental (regional) ancestry, although the local populations were identified through empirical analysis performed by our bioinformatics team. Each piece of continental ancestry is partitioned according to its regional ancestry (e.g., if an individual is 50% European and 50% East Asian, the precise origin of each of those pieces will be determined). The person's genome is also plotted against all of the known individuals in each region to show visually where he or she falls.

Below is an example plot for an individual who was determined to be 50% East Asian and 50% Latino. Latino ancestry is a mixture of European and Native American ancestry, so these groups are shown as well.
Ancestry
Determination
Use Cases
Ancestry Determination Use Cases

Ethnic ancestry is one of the most informative traits that can be predicted from DNA. In an ancestry analysis, Snapshot will determine an individual's precise genetic origins, as well as whether there is any evidence of admixture (contribution from multiple populations). This information can be used to help identify remains or to significantly focus an investigation by excluding a wide range of possible suspects or even pointing to a very small group.
Kinship
Inference What Kinship
Inference Is
Snapshot Kinship Inference™

Snapshot Kinship Inference provides highly accurate inferences about the familial relationship between two people based on their DNA, even if they are distantly related. Unlike traditional forensic DNA methods, which are extremely limited in their ability to determine kinship (see tan region in the figure below), Snapshot can detect relatedness out to 9th-degree relatives (fourth cousins). This powerful forensic analysis tool gives investigators valuable, previously unobtainable information about the DNA samples found at a crime scene - information that can save time and money and lead to more solved cases.

Thanks to the massive amount of information contained in genome-wide SNP data, using DNA extracted from two biological samples, it is possible to precisely calculate the degree of relatedness between the contributors, even if the relationship is very distant.

Traditional STR-based kinship analysis is limited to distinguishing parent/offspring relationships, often yielding inconclusive results for siblings or other second-degree relatives. Snapshot's kinship model, on the other hand, uses hundreds of thousands of SNPs to detect relatedness out to 9th-degree relationships - e.g., fourth cousins. Moreover, the precise degree of the relationship can be determined out to 6th-degree relatives (second cousins once removed) while minimizing false positives - i.e., unrelated pairs mistakenly inferred to be related.
How Kinship
Inference Works
How Snapshot Kinship Inference Works

Traditional autosomal kinship analysis uses fewer than 20 short tandem repeat (STR) loci, which lack the resolution to establish relatedness beyond parent-offspring or full siblings, and is easily confounded by mutation or mistaken testing of a close relative of the true parent. ¹ Other forensic analyses use pieces of DNA that are directly transmitted through the maternal (mitochondrial DNA) or paternal (Y-chromosome) lines; however, these approaches are limited to a small subset of relationships and have very low resolution. For example, ~7% of unrelated Europeans share the same mitochondrial haplotype, meanting that they cannot be assigned to a specific family. MtDNA and Y-STRs can only suggest that two individuals may be related but cannot say whether that relationship is close or very distant.

Dissatisfied with these limitations, Parabon's scientists set out to develop a novel algorithm that takes advantage of the massive amount of autosomal data made available by genome-wide SNP typing to compare two genomes and determine the precise degree of relatedness between the two individuals. The result is a revolutionary new test that redefines the state-of-the-art in kinship analysis.

Parabon's kinship algorithm analyzes the similarity between two genomes and uses a machine learning model to predict the degree of relatedness of the two individuals. In thousands of out-of-sample predictions, this method has proven to be highly accurate while maintaining a very low false-positive rate (i.e., unrelated pairs are almost never mistakenly inferred to be related). This is true across subjects from a range of ethnic backgrounds, including related pairs with different ethnic backgrounds. Absolute accuracy is >90% out to 3rd-degree relatives (first cousins), and Snapshot can distinguish 6th-degree relatives (e.g., second cousins once removed) from unrelated pairs with greater than 98% accuracy.

As shown in the figure above, even when Snapshot incorrectly infers the degree of relatedness between two individuals, it is almost always correct within one degree. For example, Snapshot may occasionally incorrectly predict a 4th-degree relationship to be a 5th-degree relationship, but it rarely makes the mistake of predicting a 4th-degree relationship to be a 6th-degree relationship. With this level of accuracy, you can be confident that the inferences provided by Snapshot are reliable and actionable.

[1] Chakraborty, R., et al. (1999). The utility of short tandem repeat loci beyond human identification: implications for development of new DNA typing systems. Electrophoresis, 1682-1696.
Kinship
Inference
Use Cases
How Snapshot Kinship Inference is Used

Snapshot Kinship Inference can be used to establish familial relationships between a DNA sample and previously collected DNA samples or among a set of new samples, e.g.:

If there is a chance that the perpetrator of a crime is related to the victim, Snapshot can compare the victim's DNA to a crime scene DNA sample to determine whether they are related. With just one test, investigators and include or exclude the entire extended biological family of the victim.

If DNA from a suspect cannot be obtained, but a consenting family member is willing to contribute a sample, Snapshot can establish whether that family member is related to a crime scene DNA sample.

If the identity of unidentified remains is suspected, but only distant relatives are available, Snapshot can compare DNA from the remains (even bone) to that of a relative to determine whether they are related.

According to the U.S. Department of Justice (DOJ) Bureau of Justice Statistics, over 60% of all violent crimes in 2016 [the latest period for which data is available] were committed by persons known to the victim. ¹

Knowledge of these relationships can be used to validate claims of distant kinship, establish relationship networks within groups of interest, or identify remains when close relatives are not available, such as cold cases, mass disasters, or casualties of past conflicts.

[1] Morgan R. and Kena G., Criminal Victimization, 2016, US Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, NCJ 251150, Dec 2017. https://www.bjs.gov/content/pub/pdf/cv16.pdf. Retrieved: 19 Feb 2018.
Request a Sample Report Forensic Art
Enhancement What Forensic Art
Enhancement Is
Forensic Art Enhancement

While DNA can reveal much about the appearance of a subject, information about features such as age, body mass index (BMI) or the presence of facial hair are not available within an individual's genetic code. Snapshot forensic art services provide a means of incorporating such information into a Snapshot composite when it is available from non-DNA sources.

Our Forensic Art Department - under the direction of Thom Shaw, who is certified by the International Association for Identification (IAI) in the discipline of forensic art - offers age progression, BMI alteration, and accessorization services, which may include the addition of facial hair, eyeglasses, piercings, etc. We can also create composite sketches from eyewitness accounts and combine them with traditional Snapshot composites; in this way, corroborating the witness account or adding objective phenotype information to help produce the most accurate composite possible.

In cases involving unidentified remains where a skull or partial skull is available, our forensic artists are also trained to perform digital facial reconstruction, using bone structure to enhance or give nuance to a Snapshot composite.

Collectively, these forensic art services perfectly complement what Snapshot can provide from DNA alone and together they represent a revolution in how DNA can be used in an investigation.
How Forensic Art
Enhancement Works
How Forensic Art Enhancement Works

Forensic artists are artists with special training to address forensic challenges. They have an expert understanding of the human face and how the effects of aging and body mass index (BMI) change appearance. Those trained in facial reconstruction learn how to infer the most likely distribution of muscle and soft tissue from a skull. Forensic artists who create composite sketches from eyewitness accounts are trained to conduct cognitive interviews, so as to get the most accurate portrayal from a witness' memory.

Like many domains, forensic artists are beginning to rely heavily on modern software applications to facilitate their work. Sketches formerly performed with pencil and pad can now be drawn digitally. As well, facial reconstructions once performed with clay sculpture can also be digitally sculpted. In the right hands, graphics software programs can ease the task of adding or subtracting hair, scars, and other accessories. In all cases, great skill and specialized training is still required, but the work can be more efficient and realistic thanks to these tools.
Forensic Art
Enhancement
Use Cases
Forensic Art Enhancement Use Cases
There are a number of use cases for which forensic art can be used.
Age Progression or Regression

Because age is not genetically encoded, Snapshot predicts subjects at 25 years of age by default. When investigators have reason to believe a person of interest is younger or older, our artists can adjust a composite accordingly, based on standard aging principles.

Composites Based on Eyewitness Account

Our forensic artists are trained to conduct cognitive interviews and produce composites solely from an eyewitness account. The interview and composite production is conducted online with screen sharing technology, so eyewitnesses do not have to travel. When DNA is available for the same person of interest as seen by the eyewitness, Snapshot can provide a corresponding composite from "the genetic witness" perspective. Our artists can combine a composite from an eyewitness account with one produced by Snapshot to produce a single, highly accurate rendering that contains the best that both sources of information can offer.

Accessorization

In some instances, descriptive information about a subject's accessories or distinguishing features is available that can be used to enhance a Snapshot composite. For example, a surveillance camera image may be too grainy for identification, but nevertheless suggestive that a suspect has facial hair. Similarly, an eyewitness may recall a tattoo or scar, even though they were too traumatized to remember much else. In such cases, our forensic artists can accessorize a Snapshot composite to include all available descriptive information about a subject.

Body Mass Index (BMI) Alteration

Besides the effects of aging, changes in BMI have among the largest effects on appearance. By default, Snapshot produces composites assuming the subject has a BMI of 22, which is considered average. When information is available that suggests a subject has a lower or higher than average BMI, forensic artists can appropriately alter the BMI of a Snapshot composite.

Unidentified Remains

When unidentified human remains include a skull, our forensic artists can perform facial reconstruction, literally building up the corresponding face using knowledge of facial musculature and soft tissues. Although facial features cannot be perfectly inferred from a skull, bone structure can be immensely informative about the shape of an individual's face. Snapshot predicts exterior face morphology, but when a skull is available, a forensic artist can use it to confirm or enhance a Snapshot composite based on facial reconstruction.
Facial / Skull
Reconstruction What Facial
Reconstruction Is
Snapshot Facial Reconstruction

By combining two complementary methods of estimating appearance from skeletal evidence - DNA phenotyping and forensic facial reconstruction - the Snapshot Facial Reconstruction Service produces the most fully informed recreations of antemortem appearance ever produced from skeletal remains.

How Facial
Reconstruction Works
How Snapshot Facial Reconstruction Works

Snapshot phenotyping algorithms are used to predict a decedent's appearance and ancestry using DNA extracted from bone. Independently, a traditional facial reconstruction is performed by a forensic artist who has been specifically trained to interpret Snapshot DNA Phenotyping results. Tissue depth markers are physically applied to the decedent's skull, based on DNA-determined ancestry and estimated body weight, to produce a prediction of face shape from cranial morphology. A final composite is then produced by digitally blending the two predictions.

Benefits of
Facial
Reconstruction
Benefits of Snapshot Facial Reconstruction

Combining DNA phenotyping and forensic facial reconstruction has several benefits over either method applied individually:

Traditional forensic facial reconstruction often lacks ancestry and pigmentation information about a dependent, which is why they are often depicted in grayscale.

In cases of prolonged decomposition, scavengers may remove the mandible (jawbone) from a skull. Snapshot DNA Phenotyping can provide a forensic artist with a solid prediction of jaw shape to assist with the reconstruction process.

DNA phenotyping models are tuned to explain only normal variation in appearance, whereas skull evidence may reveal distinguishing facial features that may be difficult to predict from DNA alone.

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COOL What Genetic Genealogy Is Genetic Genealogy (GG) is the combination of genetic analysis with traditional historical and genealogical research to study family history. For forensic investigations, it can be used to identify remains by tying the DNA to a family with a missing person or to point to the likely identity of a perpetrator.

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Plate 1 ACCIDENT INVESTIGATION/Airbag Related Injuries and Deaths This patient sustained a severe corneal abrasion secondary to the membrane forces associated with air bag deployment. Plate 2 ACCIDENT INVESTIGATION/Driver Versus Passenger in Motor Vehicle Collisions Contact with deploying air bags will result in injuries to the occupants, including abrasions. This patient sustained superficial abrasions overlying [...]

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Plate 1 ACCIDENT INVESTIGATION/Airbag Related Injuries and Deaths This patient sustained a severe corneal abrasion secondary to the membrane forces associated with air bag deployment. Plate 2 ACCIDENT INVESTIGATION/Driver Versus Passenger in Motor Vehicle Collisions Contact with deploying air bags will result in injuries to the occupants, including abrasions.

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Uniform Language for Testimony and Reports

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Uniform Language for Testimony and Reports

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Uniform Language for Testimony and Reports

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The Department is in the process of developing guidance documents governing the testimony and reports of its forensic experts. These documents, known as "Uniform Language for Testimony and Reports," or ULTR documents, are designed to provide guidance on the submission of scientific statements by the Department's forensic examiners when drafting reports or testifying.

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Reference Cards I have created reference cards for many of the units/activities listed below, which are designed to replace the student worksheets and some lab pages for those units. The cards are printed on card stock (back-to-back) and laminated for student use. Students…

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Forensics Problem Based Learning Scenario

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Forensics Problem Based Learning Scenario

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Forensics Problem Based Learning Scenario

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Forensic Science E-Portfolio Tasks - STEM SOS PBL Resources

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Forensic Science E-Portfolio Tasks - STEM SOS PBL Resources

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Tab 2. Field Trip pictures and reflections (Optional)

Detailed Assignments:

About me Page

Paragraph 1: provide general information about you (who you are, your interest, hobbies). Note: Do not disclose any private information and/or your full name (use first name, and last initials).

Paragraph 2: your goals for life (plan for college, life, career, and family etc.) Note: Do not disclose any private information about your family and/or full name.

Paragraph 3: Reason for taking Forensic Science, your expectations from this class.

My Journals

Each week you will write a short journal entry based on the topics covered in class. Occasionally, your teacher may provide you with a journal prompt for your page. Your journal entry should include the date and topic. It should include a paragraph. In some instance, you may also include couple of pictures.

You will receive a completion grade for these journal entries. At the end of the nine weeks your teacher expects to see minimum of 5 completed journal entries. 50 points will be assigned for completing the entries. Another 50 point will be assigned based on the content and organization.

During this school year you are responsible for creating six pages in your google site for six projects.This pages should go below your journal entries. During the first nine weeks you will choose one topic in which you did an activity to write a report in your google page. During the second and third nine weeks you will choose two topics to generate a report and in the fourth nine weeks you will choose one topic to create a report in your google page. This report must include an introduction , , objective and results . For at least two of your projects create a video (PBL) to insert in your report. conclusion

Below is a chart showing the choices for each nine weeks. Each project has its own rubric, you may see the rubric by clicking on the link or asking your teacher. To see a sample website click

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Forensic Science E-Portfolio Tasks - STEM SOS PBL Resources

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Tab 2. Field Trip pictures and reflections (Optional) Detailed Assignments: About me Page Paragraph 1: provide general information about you (who you are, your interest, hobbies). Note: Do not disclose any private information and/or your full name (use first name, and last initials). Paragraph 2: your goals for life (plan for college, life, career, and family etc.)

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Medical Examiners' and Coroners' Handbook on Death Registration and Fetal Death Reporting

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Medical Examiners' and Coroners' Handbook on Death Registration and Fetal Death Reporting

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mechanisms of death :: www.forensicmed.co.uk

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mechanisms of death :: www.forensicmed.co.uk

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A conceptual difficulty when learning about the forensic pathology of trauma, and sudden or unexpected death, is 'why did the individual die when they did?'.

Medical students - and pathology trainees - are taught what the relevant signs, symptoms and pathological findings are in diseases and conditions, but rarely are they taught about the pathophysiological disturbances that accompany potentially fatal diseases/ conditions. When dealing with traumatic events, such pathophysiological disturbances are also neglected, in favour of identifying the anatomic/ pathologic abnormality that can be seen - either by the 'naked eye' or under the microscope.

The most comprehensive resource for reviewing such 'mechanisms of death' can be found in 'Spitz and Fisher's Medicolegal Investigation of Death', and the following notes are adapted from this source.

The principle mechanisms of interest are those having an adverse effect on the heart, the brain, or both.

[Adams VI, Flomenbaum MA, Hirsch CS. Mechanisms of death. Chapter 9 In: Spitz and Fisher's Medicolegal Investigation of Death, 4th Edition (2006), Spitz WU (Ed), Charles C Thomas, Springfield, Illinois, USA]

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Medical students - and pathology trainees - are taught what the relevant signs, symptoms and pathological findings are in diseases and conditions, but rarely are they taught about the pathophysiological disturbances that accompany potentially fatal diseases/ conditions.

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Pathology Outlines - Cause, manner and mechanism of death

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Pathology Outlines - Cause, manner and mechanism of death

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Page views in 2019: 4,369

Page views in 2020 to date: 6,518

Cite this page: Harle L. Cause, manner and mechanism of death. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/forensicscauses.html. Accessed September 14th, 2020.

Defined as how the death came about; a judgment based on circumstances surrounding the fatal event

In most jurisdictions the following categories are used:

Natural: due entirely (or nearly so) to natural disease processes

Homicide: due to a volitional act of another person with the intent to cause fear, harm or death
Homicidal manner does not indicate a criminal homicide, which is determined by the legal process and not by the certifier of death

Suicide: due to injury that occurred with the intent to induce self harm or cause one's own death

Accident: due to injury when there is no evidence of intent to harm

Undetermined: inadequate information regarding the circumstances of death to determine manner; example: individual found unconscious with massive subdural hemorrhage; in the absence of information on the events leading up to death, it is impossible to determine if the hemorrhage is due to accidental fall, homicidal violence, etc.

When death is due to a combination of natural and unnatural events, preference is generally given to the nonnatural cause; example: a man suffers a myocardial infarction while swimming in the ocean, loses consciousness, and drowns; the manner of death is ruled accident, as he may potentially have survived if the fatal myocardial infarction had occurred on land

The "but for" principle asks the question "But for the inciting injury (or event), would the decedent still be alive?"

In most jurisdictions, deaths due to motor vehicle collisions are considered accidental in manner

Deaths due to complications of medical therapy that are reasonably expectable (e.g. neutropenia due to chemotherapy, digoxin toxicity) are considered natural

Deaths due to improper use of medical devices or improper therapy (e.g. malfunctioning morphine drip, failure to repair obvious arterial injury inflicted during surgery) are considered accidental

While acute alcohol or drug toxicity is considered an accidental death, deaths due to consequences of chronic substance abuse (hepatic cirrhosis due to ethanol abuse, endocarditis secondary to IV drug use) are conventionally considered natural in manner

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Page views in 2019: 4,369 Page views in 2020 to date: 6,518 Cite this page: Harle L. Cause, manner and mechanism of death. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/forensicscauses.html. Accessed September 14th, 2020.

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What to Watch After ‘Tiger King’: 12 Great True-Crime Documentaries on Netflix - The New York Times

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What to Watch After ‘Tiger King’: 12 Great True-Crime Documentaries on Netflix - The New York Times

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It looks as if most of us are going to spend some time at home, and goodness knows diversions are welcome. Whatever it may say about these bleak times, true-crime documentaries (in feature film and series form) have proven among the most bingeable of entertainments, drawing us ever deeper into their webs of suspects, clues and whiteboards. "Tiger King," while not a straight true-crime series like these others, has elements of some of the more gripping stories on this list.

Netflix knows that a good plot twist or surprise witness keeps us from reaching for the remote, and the streaming service has filled its library accordingly. These are a few of its best offerings.

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Netflix had its first big nonfiction cultural touchstone in 2015 with this 10-part examination of the trials of Steven Avery, a Wisconsin man who was released from prison after 18 years when DNA evidence cleared him of one murder, only to find himself back on trial two years later for another. The filmmakers' access to many of the participants puts the viewer right in the middle of the engrossing trial, and their skill for constructing cliffhangers makes it hard to resist bingeing the entire thing. ( Read the New York Times review.)

Stream it here.
The most influential predecessor to "Making a Murderer" was most likely this Peabody Award-winning docu-series, which originally aired in eight parts on French and British television in 2004, with additional episodes added in 2013 and 2018. Covering the arrest and trial of the novelist Michael Peterson, accused of murdering his wife in December of 2001, it initially seems a fairly straightforward story; it turns out to be anything but. The director Jean-Xavier de Lestrade uses the expansive running time and his extensive access to Peterson's attorneys to construct a detail-oriented account of how a defense is mounted and presented, and to delve into the fascinating contradictions of its enigmatic subject. ( Read the New York Times review.)

Stream it here.
The bizarre death of Brian Wells, a pizza delivery man forced to rob a bank with a bomb attached to his body, is the focus of this 2018 four-parter from the directors Barbara Schroeder and Trey Borzillieri. The filmmakers immerse themselves in the criminal subculture of Erie, Penn., and find a colorful cast of characters there - particularly Marjorie Diehl-Armstrong, who may or may not be the mastermind of the title. Like many a good docu-series, it embraces the story's complexity, following the many strands, fake-outs and dead ends of this spider web of a crime, in which the actions and motivations of everyone (including the victim) are up for debate.

It's not hard to anoint Errol Morris the godfather of contemporary true crime cinema, as his 1988 film "The Thin Blue Line" established so many of the genre's conventions. If nothing else, it seemed like good manners for Netflix to invite the filmmaker to craft this masterful blend of documentary and drama, truth and fiction, fact and conjecture. Focusing on the apparent suicide of Frank Olson in 1953, a civilian scientist working for the U.S. Army, Morris investigates not only the event in question but also the cloudy circumstances surrounding its subsequent explanation - all wrapped around the filmmaker's conversations with Olson's son, who has spent most of his life trying to make sense of his father's death. ( Read the New York Times review.)

Stream it here.
Many of the best true-crime documentaries have a pronounced "truth is stranger than fiction" element, but Skye Borgman's 2019 feature turns that aspect up to 11. It tells the story of Jan Broberg Felt, who was abducted by a neighbor and family friend, Robert Berchtold, when she was only 12 years old - and then, improbably and inexplicably, abducted again several years later. It sounds impossible, but Borgman deftly demonstrates how her abductor exploited the trust of his community (and, shockingly, his proximity to her parents) for his nefarious purpose.

When Alex Lewis was 18 years old, he woke from a coma with no memories at all, of his life or the people in it. He remembered only Marcus, his twin brother, who was left to fill in all of the gaps. But there is more to Alex's story than his brother told him - childhood secrets and horrifying traumas, which he consciously chose to withhold. And given the choice, the director Ed Perkins asks, would you do the same? This gutting and powerful documentary reconstructs the real story of Alex's childhood as he discovers it, and in doing so, asks vital questions about the rose-colored glasses through which we consider our past and present. ( Read the New York Times review.)

This seven-part series begins as an investigation into the savage murder of Sister Catherine Cesnik, a half-century old Baltimore cold case that may implicate the police department, the local Archdiocese and the Catholic Church. But it's not just another sprawling, shocking page-turner (though it is certainly that, and a gripping one to boot). The director Ryan White's sensitive presentation and brilliant structure refuses to sensationalize the material, devoting long, haunting stretches of the series to victims' trauma and institutional maleficence. It never lets the viewer forget about the human toll of this crime, and not just on the woman at its center. ( Read the New York Times review.)

Stream it here.
The events dramatized in the 2014 Oscar nominee " Foxcatcher," and the actions of its central character, John du Pont, seemed so grotesque they almost had to be exaggerated. This bravura documentary account suggests, however, that the dramatists soft-balled the strangeness. The trove of news reports, home movies and self-produced infomercials presented here paint a fascinating picture of an unbalanced, paranoid danger, a ticking bomb that everyone around him pretended not to hear lest they risk losing access to his money and power. ( Read the New York Times review.)

Stream it here.
The stories of Audrie Pott and Daisy Coleman, two teenage girls sexually assaulted by peers and then subjected to online harassment and worse, are paired and explored in this compelling 2016 indictment of technological apathy and rape culture. One story results in a suicide; the other ends in activism, and the directors Bonni Cohen and Jon Shenk suggest that those wildly divergent outcomes have everything to do with communities in which young women like these are not to be believed, or even trusted. It's a powerful, infuriating work. ( Read the New York Times review.)

Stream it here.
This 2016 mystery takes a deep dive into the arrest and trial of Amanda Knox, an American student in Italy convicted of participating in her roommate's murder. But the film is just as interested in the intense media scrutiny surrounding the case and in how the biases and excesses that informed that coverage may have filtered into the courtroom. And it's no open-and-shut case; the filmmakers keep their subject an enigma and allow viewers to draw their own conclusions about who she is and what she knew. ( Read the New York Times review.)

"I tell people now," chuckles one of the residents of Antelope, Ore., "and they still don't believe it." It's hard to blame them. Maclain and Chapman Way's six-part documentary exposé of the guru known as Bhagwan Shree Rajneesh and the followers who took over that desert area in the early 1980s is a twisty, twisted tale of guns, sex, immigration fraud, wiretapping, mass food poisoning and attempted assassinations. Every new ripple is more jaw-dropping than the last. ( Read the New York Times review.)

Most true-crime documentaries traffic in so much death and unpleasantness, reveling in gory details and villainous sociopathy, that the notion of a "feel good" true-crime doc seems odd. But that's exactly what the director Jacob LaMendola got when he spun the yarn of Juan Catalan, arrested for a murder he didn't commit, whose alibi was unexpectedly confirmed by a "Curb Your Enthusiasm" location shoot. (Larry David himself appears to take some credit.) Catalan's triumph is both thrilling and moving - and the film runs an efficient 40 minutes, which makes it the perfect chaser to a daylong docu-series binge.

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What to Watch After 'Tiger King': 12 Great True-Crime Documentaries on Netflix

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It looks as if most of us are going to spend some time at home, and goodness knows diversions are welcome. Whatever it may say about these bleak times, true-crime documentaries (in feature film and series form) have proven among the most bingeable of entertainments, drawing us ever deeper into their webs of suspects, clues and whiteboards.

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New Algorithm Examines Crime-Scene Bullets Segment by Segment

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New Algorithm Examines Crime-Scene Bullets Segment by Segment

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On the morning of March 22, 1915, residents of the small town of West Shelby, New York, awoke to a horrific scene. A woman clad only in a bloodied nightgown lay shot to death in the snow on the doorstep of an immigrant farmhand, Charles Stielow. Across the street, in the farmhouse where Stielow had recently begun work and where the dead woman had kept house, 70-year-old farmer Charles Phelps was found shot and unconscious. He died a few hours later.

After finding that Stielow lied when he told investigators he did not own a gun, the police arrested him on Aug. 21, 1915. During Stielow's trial, a self-proclaimed criminologist, Albert Hamilton, testified that the nine bumps he said he found inside the barrel of Stielow's .22 caliber revolver matched the nine scratch marks he had identified on the same caliber bullets at the crime scene. Although Hamilton never showed his evidence to the jury, declaring the findings were so technical they could only be discerned by an expert, Stielow was found guilty of murder in the first degree. He was sentenced to death in the electric chair and sent to Sing Sing prison to await execution.

Several people familiar with the case, including the deputy warden at Sing Sing, became convinced that Stielow was innocent and that his confession contained words that the farmhand, who was mentally challenged, could not have understood let alone uttered. Just one week before Stielow was scheduled to be electrocuted on December 11, 1916, the Governor of New York called for a reinvestigation. A firearms expert from the New York City police department compared the bullets from the murder scene with those test-fired from Stielow's gun. Even by eye, the markings on the two sets of bullets did not look similar but to make certain, optician Max Poser studied them under the microscope. The bullets from the murder scene could not have been fired from Stielow's gun, he declared.

Poser's analysis not only set Stielow free, it made history as one of the first examples of applying modern forensic techniques to identify firearms.

Today, forensic scientists still use a type of microscope, developed and perfected by two of Poser's colleagues in the 1920s, to examine crime-scene bullets or cartridge cases-the metal cylinders that hold the powder and bullets before they are fired. Known as a comparison microscope, the device consists of two microscopes connected by an optical bridge.

The microscope's split screen allows for a side-by-side comparison of the miniscule scratch marks, or striations, on bullets or cartridge cases found at the crime scene with the markings on bullets or cases test fired from a particular gun. These striations are imparted on bullets as they squeeze through the spiral windings, called rifling, down a gun barrel at high speed and pressure.

The firearms examiner adjusts the position of the test-fired bullet until its striations best match those on the crime-scene bullet. In this way, the examiner can provide her expert opinion about whether the crime-scene bullets came from the same gun that was test fired.

The method is highly successful, but the comparison results are subjective, dependent on the expertise of the examiner. The visual comparison does not allow the firearms expert to objectively quantify the level of uncertainty in the comparison. For example, what is the likelihood of obtaining the comparison result if the bullets in fact came from the same firearm or from different firearms? Courts now prefer such statistical information, which is, for example, routinely provided by DNA experts when they testify about genetic evidence.

Last year, NIST scientists premiered a computer-based comparison method that can provide this numerical information. The algorithm, known as congruent matching profile segments (CMPS), relies on detailed 3D maps.

"Firearm experts are actually quite good at making comparisons, so it's not a question of replacing human judgement with a computer algorithm," noted NIST scientist Robert Thompson, a member of the NIST team. "The algorithm provides a way to mathematically rate the reliability of the expert's findings."

Crucially, instead of comparing the overall map, or profile, of one bullet to another, the algorithm first divides the profile of each crime-scene bullet into tiny, non-overlapping segments. Then, it looks to see if any of the individual segments match up with any section of a test-fired bullet.

The segmentation is an important feature because crime-scene bullets usually deform or fragment after ricocheting off a solid surface or rapidly decelerating in the human body. As a consequence, rifling striations may be erased, expanded or shifted in position. Comparing the entire profile of such a deformed bullet with the pristine markings of a bullet test-fired into a water tank may indicate a low probability of a match--even though the bullets may have been shot by the same gun. Searching for matching features segment-by-segment provides a much more accurate way of comparing crime-scene and test bullets.

Before the team applied their comparison method, the researchers used image reconstruction techniques to "straighten out" and display as parallel scratch marks that had become distorted or slanted as the bullets deformed. But even after the markings on the crime-scene bullets are straightened, they may not line up with the position of similar markings on the test bullets. That's where CMPS comes in, says PML scientist Johannes Soons. The algorithm takes a small section of the markings on the deformed bullet and hunts for any place on the test bullets that may prove a match. The software then evaluates how many segments were found at a correct position relative to the markings on the test-fired bullet. The method builds upon an older algorithm, developed by PML scientist John Song, that compares impressed firearm marks on cartridge cases.

In the initial study that the NIST-led team reported last December in Forensic Science International, the scientists only used the CMPS method to compare non-deformed bullets fired from known guns. The team shot 35 9-mm Luger bullets into a water tank from 10 gun barrels that had consecutively manufactured.

Each barrel in the study imprinted scratch marks on the bullets. The researchers found that CMPS more accurately determined the origin of each bullet than a comparison method that did not divide the bullet markings into segments.

In the team's newest study, published in the January Forensic Science International, the researchers for the first time employed the CMPS method to examine deformed bullets. The team fired 57 bullets with varying degrees of fragmentation from the same 9 mm pistol into a water tank. To create bullet fragments with varying degrees of deformation, the researchers aimed the gun at a slight angle, so that the bullets struck the sides of a heavy gauge steel tube placed in front of the water tank instead of shooting straight into the water.

The team conducted two kinds of tests using the image reconstruction software and the CMPS algorithm. The researchers compared severely distorted markings on bullets with those imprinted on near-pristine reference bullets shot directly into the water tank. They also compared deformed bullets before and after image reconstruction that straightened the distorted markings. The scientists found that together, image reconstruction and CMPS significantly improved the ability to match the markings on deformed bullets with each other and with the pristine bullets.

The team is now planning to conduct further studies to test the CMPS method. With the freedom-and perhaps the life-of a defendant hanging in the balance, these studies are critical for determining if-and when-CMPS can be routinely incorporated into the analysis and testimony of firearm experts, says Soons.
Republished courtesy of NIST. Photo: When a bullet is fired from a gun, the barrel leaves distinctive scratch marks on the surface of the bullet. These microscopic marks are highly similar for bullets fired from the same gun, meaning they can be used for forensic comparison, matching bullets taken from a crime scene to a particular gun. However, crime-scene bullets are often deformed from collisions, which can make direct comparison difficult. Now, NIST researchers have developed a new algorithm that makes this matching more accurate, by dividing the markings on the deformed bullets into segments, and correlating those segments with the reference bullet. Credit: Sean Kelley/NIST

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New Algorithm Examines Crime-Scene Bullets Segment by Segment

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On the morning of March 22, 1915, residents of the small town of West Shelby, New York, awoke to a horrific scene. A woman clad only in a bloodied nightgown lay shot to death in the snow on the doorstep of an immigrant farmhand, Charles Stielow.

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FARO Public Safety - Forensics | Public Safety Solutions

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FARO Public Safety - Forensics | Public Safety Solutions

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Revolutionary solutions to digitally capture the scene, analyze the data in 3D, and deliver impactful courtroom materials. Investigators and forensic experts around the world trust FARO ® solutions to document the evidence at crime, crash, and fire scenes.

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Revolutionary solutions to digitally capture the scene, analyze the data in 3D, and deliver impactful courtroom materials. Investigators and forensic experts around the world trust FARO ® solutions to document the evidence at crime, crash, and fire scenes.

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Murderpedia, the encyclopedia of murderers

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Murderpedia, the encyclopedia of murderers

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Murderpedia, the encyclopedia of murderers

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Murderpedia, the free online encyclopedic dictionary of murderers, mass murderers and serial killers.

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Our Products
Murder at Old Fields
Murder at Old Fields, the first case in the Case History forensic science series, is an exciting Forensic Science Lab Activity for middle and high school students. Based on the 1842 double-murder of Alexander and Rebecca Smith at their farmhouse in Old Fields, Long Island, students examine evidence and conduct labs based on the historical facts of this case.

There are two versions of the Murder at Old Fields activity; a real-world kit and an online version.
Diablo Highway
Diablo Highway is the second lab activity in the Case History forensic science series. the real-world kit available now contains eleven lessons for middle and high school students based on the double-murder of Hazel Frome and her daughter Nancy that occurred in March 1938 on a desert road in Southwest Texas. Diablo Highway is problem-based learning that supports the three-dimensions of learning outlined in the Next Generation Science Standards.

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Murder at Old Fields Murder at Old Fields, the first case in the Case History forensic science series, is an exciting Forensic Science Lab Activity for middle and high school students. Based on the 1842 double-murder of Alexander and Rebecca Smith at their farmhouse in Old Fields, Long Island, students examine evidence and conduct labs based on the historical facts of this case.

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How Accurate are Crime Shows on TV? Debunking 7 Common Myths | Rasmussen College

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How Accurate are Crime Shows on TV? Debunking 7 Common Myths | Rasmussen College

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At any given moment of any day, crime dramas dominate television airwaves.

You've seen them. The first scene opens with a team of detectives-clad in gloves and biohazard suits-lifting fingerprints off of bed sheets, shower curtains and windowsills. After the commercial, those same detectives immediately match those prints to a seedy-looking suspect. By the end of the episode, the detectives have located said suspect and elicited a confession. And that's a wrap-in 40 minutes flat.

Whether you prefer the cerebral forensic experience of CSI, the boots-in-the-streets grittiness of Law & Order: SVU, the sinister Robin Hood-style of Dexter or some combination thereof, you've seen that forensic work is at the heart of solving crimes.

And maybe you're one of those people who's watching thinking, "I could do that!" But if you're looking for a criminal justice career based on what you see each week on the small screen, think again. Experts agree that the fantasy of TV doesn't match up very well with the reality of the job.

So in an effort to paint a more realistic picture of what aspiring criminal justice professionals can expect, we enlisted an expert to set the record straight about seven common crime show myths.

The truth about 7 crime show myths

Myth #1: Detectives analyze the evidence

"First and most annoying is the portrayal of crime scene personnel also doing detective work," says Brian McKenna, retired Lieutenant and Crime Scene Investigator. "In most agencies, crime scene work and investigations are two separate functions."

McKenna goes on to explain that crime scene investigators process the crime scenes, package up whatever evidence they find and send it off to a lab. "Rarely do they participate directly in criminal investigations, especially in larger agencies," he adds. Unlike what you see on screen, detectives rarely set foot in the lab.

Crime scene technicians (CSTs), however, do spend time both on site and in their labs, as they have training in the correct way to collect evidence. But these professionals aren't as involved in the actual investigation process as, say, a detective is.

Myth #2: Crime scenes are processed quickly

"I roll my eyes about the speed at which crime scene investigators [on TV] get results back from the lab," McKenna says. "It takes a very long time to process a lot of the evidence obtained, especially Hollywood's most popular kind of evidence-DNA." He explains that processing DNA evidence takes well over 50 hours of lab work-which equates to more than six workdays. And that's only if the lab techs have a clear schedule.

The Public Agency Training Council offers a breakdown of what DNA processing looks like in a criminal case.

And after all that work, the DNA results might still prove meaningless. The FBI's Combined DNA Index System (CODIS) database is considered the world's largest repository of known offender DNA records, but it's not perfect.

If DNA is collected from a suspect whose fingerprints have not been entered, guilty or not, that suspect will not be identified using DNA. Moreover, if a sample collected is very small, poorly preserved or highly degraded, matching it can be very difficult.

Myth #3: Crime scene working conditions are consistent

Hopeful CSTs often don't consider the difficult working conditions they are likely to face while collecting evidence. For example, painstakingly gathering miniscule samples is a whole different ballgame in the snow or around a crash site baking in the sun. McKenna says you rarely see an accurate depiction of the harsh and uncomfortable working conditions of a crime scene.

"The scenes are often dirty, sometimes bloody, hot, cold or even outdoors in bad weather," he explains. "In many cases it is also necessary to crawl on the floor, under a car or otherwise work from awkward, dirty or uncomfortable positions."

Myth #4: Crime scene professionals turn off emotions when they're on the job

No matter how many crime shows you've watched, nothing on TV can compare to the real thing. Even for those who really get into the science of forensic collection, walking into the aftermath of a crime or disaster takes some getting used to. In other words, you won't be coolly sipping your coffee while pointing out spatter patterns like an actor on TV.

"Many crime scenes are gruesome and potentially depressing. Unlike those portrayed on television, violent deaths are very ugly," McKenna says. He adds that it's not just dramatic homicides and major assaults that CSTs have to process. They're also on the scene of suicides, fatal car wrecks and accidental deaths from other causes. "It isn't pleasant, and some people can't handle it."

McKenna says of course, many individuals get used to the crime scenes and find the work very rewarding. But your own reaction to the traumatic loss of life is definitely something to consider before pursuing a career working on crime scenes.

Myth #5: All crime scenes are processed for evidence

"I wish [people] knew about the limitations of this kind of work," McKenna says. "Since it takes so much time, a lot of crime scene processing has to be abbreviated or left out altogether. There just isn't enough time or resources to process many cases, especially in larger agencies with high crime rates."

As much as departments would like to gather and process evidence to add to the prosecution of every crime, limited resources demand a triage system. McKenna says that some large, urban police departments don't process burglary scenes at all unless the loss exceeds $1,000. Simple theft, vandalism and even auto thefts generally don't undergo extensive processing either.

Myth #6: Every day is exciting when you're a CST or police officer

"Crime scene processing is a very tedious, time-consuming process when done correctly," McKenna emphasizes. "Every bit of possible evidence must be carefully photographed, gathered, packaged, logged and later placed into evidence."

And for larger cases, McKenna says measurement must also be taken and the locations of the various pieces of evidence noted for later inclusion in a detailed crime scene sketch. "Like other crime scene investigators, I was always very careful to seize anything and everything even hinting that it might be evidence, because you can never know what might later prove to be important."

Precision is essential. Any of the work done by a CST or police officer could end up being the subject of a criminal investigation. For example, properly written reports could be used to help attorneys prosecute suspects. Conversely, defense attorneys could use sloppiness and skipped protocols to argue a breach in the chain of custody.

"It's no surprise that Hollywood ignores this aspect of crime scene work, because it would bore viewers to watch it," McKenna says. "But aspiring crime scene technicians need to know how tedious the work is."

He also cautions crime-solving hopefuls against thinking every case they're involved in will be a high-profile case (like a homicide or kidnapping). "Even though many crime scenes are not processed, the vast majority of those that are processed are hardly ever major cases," he says.

Myth #7: A criminal justice degree will automatically qualify you to be a police officer, CST or forensic scientist

"Crime scene technicians must almost always start out as beat cops," McKenna says. "This is generally not true with lab personnel, but it is true for technicians who actually process crime scenes." The path to crime scenes isn't guaranteed upon graduation.

McKenna points out that most agencies require at least five years of experience as a patrol officer before advancement to a more specialized position. "I am virtually positive that no agency would allow any officer to transfer to a CSI position until after he or she has completed the academy and made it off probation (a process that takes a little over a year)."

But a degree is still a step in the right direction. McKenna says most agencies require at least an associate degree, with a preference for a bachelor's. A degree will put you on the right path and provide you with a good foundation for a career in criminal justice, but additional training and a passing grade on the Police Officer Selection Test (POST) is also needed before you're able to work in the field.

If you're looking to work at a state facility like the Bureau of Criminal Apprehension (BCA), forensic training is even more extensive.

Keep investigating

Is it all you thought it would be? Are there things in this list that shocked or surprised you? You might also be surprised to learn that crime show myths do more than perpetuate a few misconceptions-they have the ability to alter our entire justice system.

Learn more in our article, 7 Ways the CSI Effect is Altering our Courtrooms (For Better and For Worse).
RELATED ARTICLES:
EDITOR'S NOTE: This article was originally published in December 2012. It has since been updated to include information relevant to 2017.

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How Accurate are Crime Shows on TV? Debunking 7 Common Myths

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At any given moment of any day, crime dramas dominate television airwaves. You've seen them. The first scene opens with a team of detectives-clad in gloves and biohazard suits-lifting fingerprints off of bed sheets, shower curtains and windowsills. After the commercial, those same detectives immediately match those prints to a seedy-looking suspect.

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ToxTutor - Dose Estimates of Toxic Effects

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ToxTutor - Dose Estimates of Toxic Effects

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Dose Estimates

Dose-response curves are used to derive dose estimates of chemical substances.

Historically, LD50 (Lethal Dose 50%) has been a common dose estimate for acute toxicity. It is a statistically derived maximum dose at which 50% of the group of organisms (rat, mouse, or other species) would be expected to die. LD50 testing is no longer the recommended method for assessing toxicity because of the ethics of using large numbers of animals, the variability of responses in animals and humans, and the use of mortality as the only endpoint. Regulatory agencies use LD50 only if it is justified by scientific necessity and ethical considerations.

The Three Rs

The current practice for estimating acute toxicity emphasizes the following approaches, known as the Three Rs:

1. Reducing the number of animals used. For example, the oral LD50 approach has been replaced in some circumstances by anup-and-down method in which animals are dosed one at a time.

2. Refining care and procedures to minimize pain and distress.

Other dose estimates also may be used.

Lethal Doses/Concentrations

Lethal Dose 0% (LD0) - represents the dose at which no individuals are expected to die. This is just below the threshold for lethality.

Lethal Dose 10% (LD10) - refers to the dose at which 10% of the individuals will die.

Lethal Concentration 50% (LC50) - for inhalation toxicity, air concentrations are used for exposure values. The LC50 refers to the calculated concentration of a gas lethal to 50% of a group. Occasionally LC0 and LC10 are also used.

Effective Doses (EDs)

Effective Doses( EDs) are used to indicate the effectiveness of a substance. Normally, effective dose refers to a beneficial effect such as relief of pain. It may also stand for a harmful effect such as paralysis. Thus, the specific endpoint must be indicated. The usual terms are:

Table 1. Typical terms for describing effective doses

Toxic Doses (TDs)

Toxic Doses ( TDs) are used to indicate doses that cause adverse toxic effects. The usual dose estimates include:

Table 2. Typical terms for describing toxic doses

Determining the Relative Safety of Pharmaceuticals

Toxicologists, pharmacologists, and others use effectiveand toxic dose levels to determine the relative safety of pharmaceuticals. As shown in Figure 1, two dose-response curves are presented for the same drug, one for effectiveness and the other for toxicity. In this case, a dose that is 50% to 75% effective does not cause toxicity. However, a 90% effective dose may result in a small amount of toxicity.

Figure 1. Dose-response curves representing effective dose and toxic dose for the same drug
(Image Source: NLM)

It should be noted that a desired effect in a drug is often an undesired effect with an environmental chemical.

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Dose-response curves are used to derive dose estimates of chemical substances. Historically, LD50 (Lethal Dose 50%) has been a common dose estimate for acute toxicity. It is a statistically derived maximum dose at which 50% of the group of organisms (rat, mouse, or other species) would be expected to die.

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TPT Co-Productions | Forensics: Beyond the CSI Effect | PBS

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TPT Co-Productions | Forensics: Beyond the CSI Effect | PBS

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TPT Co-Productions
Television dramas often provide an inaccurate portrayal of how evidence is gathered and used in a criminal investigation. Learn how law enforcement applies the scientific method to their work and why this fundamental understanding outlines the basis behind the science of forensics.

Aired: 10/04/14

Rating: TV-G

Problems Playing Video? Report a Problem |

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TPT Co-Productions | Forensics: Beyond the CSI Effect

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TPT Co-Productions Television dramas often provide an inaccurate portrayal of how evidence is gathered and used in a criminal investigation. Learn how law enforcement applies the scientific method to their work and why this fundamental understanding outlines the basis behind the science of forensics. Aired: 10/04/14 Rating: TV-G Problems Playing Video?

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Introduction:

The adult human skeleton is a framework of 206 bones and is anatomically divided into two parts, the axial skeleton, and the appendicular skeleton.

Axial Skeleton:

The axial skeleton is the core of the skeleton, it consists of the following 80 bones:

: 22 bones
: 1 bone
: 32 bones
: 24 bones
: 1 bone

Appendicular Skeleton:

The appendicular skeleton is attached to the axial skeleton. It consists of 126 bones.

: 4 bones (Scapula and clavicle).
: 6 bones (Humerus and radius).
: 54 bones (Carpals, metacarpals, and phalanges).

Bony Pelvis: 2 bones (Os coxae).

: 8 bones (Femur, patella, tibia, and fibula).
: 52 bones (Tarsals, metatarsals, and phalanges).

Functionally, the bones primarily give support to the appendages and protect the fragile organs of the body such as the brain, spinal cord, heart, and lungs.
They also store calcium and phosphorus in the hard bone matrix, which can be released when needed elsewhere.
The bumps, ridges, and grooves on the surface of bones provide attachment sites for the skeletal muscles.
Additionally, many bones contain a soft tissue called marrow that produces new blood cells and stores fat.

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The adult human skeleton is a framework of 206 bones and is anatomically divided into two parts, the axial skeleton, and the appendicular skeleton. The axial skeleton is the core of the skeleton, it consists of the following 80 bones: : 22 bones : 1 bone : 32 bones : 24 bones : 1 bone The appendicular skeleton is attached to the axial skeleton.

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Forensic Science, Crime Scene Investigations and Pathology

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Forensic Science, Crime Scene Investigations and Pathology

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For many people, forensics is a fascinating but confusing field that is full of mystery and intrigue. Whether it's learning more about how criminal evidence is collected and stored or finding out how the legal system uses this information, everyone should explore the world of forensics. A skilled team of expert authors write all of our articles, which we hope will be informative and interesting to our huge and diverse readership.

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Forensic Science, Crime Scene Investigations and Pathology

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For many people, forensics is a fascinating but confusing field that is full of mystery and intrigue. Whether it's learning more about how criminal evidence is collected and stored or finding out how the legal system uses this information, everyone should explore the world of forensics.

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The principal mission of the Division of Forensic Sciences, commonly referred to as the "crime lab" is to provide quality and timely scientific analyses of physical evidence to law enforcement agencies operating in Westchester County. The laboratory also provides expert scientific testimony to the various courts in our jurisdictional area. The various units that comprise this division examine evidentiary materials such as blood, tissue, drugs, footwear impressions, fibers, hairs, glass etc.

To promote these objectives various quality assurance measures have been instituted over the years to ensure the legal system of the accuracy of the work product of our laboratory. The quality of this work is affirmed through the accreditations of the laboratory by both private and governmental accrediting bodies. The division is proud to have taken a leadership role in the pursuit of these accreditations.

In 1991 the Westchester County Forensic Science Laboratory became the first full service forensic laboratory in the Northeast to gain accreditation by the American Society of Crime Laboratory Directors - Laboratory Accreditation Board (ASCLD/LAB).

Additionally, in 1999, our laboratory was the fourteenth laboratory in the country to receive accreditation in Forensic Deoxyribonucleic Acid (DNA) Analysis. In 2001 we were one of the first two laboratories in the country to obtain accreditation from ASCLD/LAB for Crime Scene Investigation. The laboratory also maintains accreditation with New York State Division of Criminal Justice Services with oversight by the New York State Commission on Forensic Sciences. New York State is presently one of only a few states to mandate accreditation of public forensic science laboratories.

In 2016 The ANSI National Accreditation Board (ANAB) announced a merger with ASCLD/LAB, therefore going forward all accreditation would be administrated by ANAB.

To maintain our accreditation by ANAB and N.Y.S/Commission on Forensic Sciences our laboratory is constantly striving to ensure that the services delivered meet all the expectations of our customers all of the time. We include as our customers the court system, jurors, prosecutors, defense attorneys, law enforcement officers, crime victims, suspects, and defendants. This is done through a three-pronged approach.

Firstly the laboratory is subjected to periodic inspections by ANAB and internal audits every year to ensure the overall proper operation of the laboratory.

Secondly, individual analysts are encouraged to undertake continuing education, participate in training courses and to keep abreast of the latest developments in their fields. Laboratory staff members actively participate in organizations such as the Northeastern Association of Forensic Scientists, and the American Academy of Forensic Sciences. The analysts are also encouraged to obtain certification from the American Board of Criminalistics (ABC) and other certifying bodies. It is noteworthy that a significant number of our analysts are certified as either Diplomates or Fellows by the ABC.

The last and the most important leg of this triad is that of testing the laboratory's precision and accuracy through a rigorous program of proficiency testing. Every analyst in the laboratory annually undergoes at least one proficiency test from an external proficiency test provider.

The division has been a very active partner with the law enforcement community of Westchester County, providing countless courses and presentations, which promote the use and understanding of scientific evidence in criminal investigations.

The division participates in community outreach by offering tours to local educational institutions and through an active internship program conducted in conjunction with a number of area schools.

It is this constant process of evaluation, improvement and dedication to the needs of local law enforcement that keeps our laboratory on the cutting edge of the forensic sciences. The division strives to provide our county with the most advanced analysis of physical evidence in a cost-effective way, thus contributing to the increased safety of Westchester County residents.

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The principal mission of the Division of Forensic Sciences, commonly referred to as the "crime lab" is to provide quality and timely scientific analyses of physical evidence to law enforcement agencies operating in Westchester County. The laboratory also provides expert scientific testimony to the various courts in our jurisdictional area.

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Hair Under the Microscope - Compound and Stereo Microscope Observations

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Hair Under the Microscope - Compound and Stereo Microscope Observations

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Our hair grows from follicles located under the skin and has two main parts. Part of the hair that remains under the skin inside the follicle is referred to as the root while the part that protrudes to the surface (head, arms etc) is known as the shaft. The base of the root (hair root) is referred to as the hair bulb and is the part through which the base of the hair receives nutrients for the formation of new cells.

As the base takes in nutrients, new cells are formed and move up the root to become part of the shaft. Over time, these cells also undergo a process referred to as keratinization (maturation process) where they lose their nucleus and fill with a fibrous protein. Therefore, hair can simply be described as strands of keratinized protein.

Main parts/layers of the hair shaft:

Cuticle - This is the outer part composed of overlapping keratin

Cortex - The cortex makes up the middle layer. It's also responsible for giving the natural color of the hair as well as its physical appearance (curves etc)

Medulla - This is the central core made up of round cells (this is largely present among those with thick hair)

Microscopy

Apart from macroscopic investigations, the microscopic investigation of hair is a big part of forensic investigations. However students can use a microscope to observe and study the characteristics of a hair fiber/strand including pigmentation, scales as well as the pattern of the medulla.

A stereo microscope is typically used for the initial examination of hair (mounted and unmounted) before moving on to the compound microscope. This is because a stereo microscope has been shown to be particularly ideal for viewing such characteristics as color, shape, texture and length of hair, which are the eternal characteristics.

A strand of hair - students can obtain different types of hair such as hair from human body, from a dog, cat etc

Using the tweezers, gently pick and place the hair strand under low power stereo microscope

Observe and try to see if there are differences between different types of hair

Under the stereo microscope, students will be able to see the hair structure as a strand that may appear to have tiny fibers or fragments on its surface. The stereo microscope will not only show the shape of the hair (twisted etc) and such fragments on its surface, but also the color of the hair strand. When viewing different types of hair, students will also be able to differentiate the thickness between different strands.

There are several procedures that can be used to view different structures of the hair.

Make a thin layer of nail polish at the central part of a clean glass slide

Using a brush, brush over the nail polish to create an even thin layer of the nail polish

Using the tweezers, place one or several strands of hair on the central part of the slide with nail polish

Allow the slide to stand for about 10 minutes or until the nail polish is tacky-dry

Using the tweezers, pull off the hair strands from the slide

Place the slide under the microscope and observe using low power objectives

* Latex can be used in place of nail polish

This procedure is used for the purposes of viewing the scale cast of hair strands. Here, the nail polish/latex is used to attach and retain the scale cast that remains on the slide once the hair strands are pulled off.

It is worth noting that the purpose of this procedure is not to view the internal structure of the hair strand, but the outer layer of hair that contain the scales. Once the hair strands are pulled off, the scales remain attached onto the slide and can be viewed using lower power objectives.

Using this procedure, students have the opportunity to view different types of hairs and get to differentiate the characteristics of the scales.

Observing the Medulla Under Compound Microscope

This is a whole mount procedure that involves viewing the hair strand in order to observe and study the medulla.

Place a drop of water at the center of a microscope glass slide

Using a pair of forceps, place a few strands of hair onto the drop of water (or any other mountant used)

Place the slide under the microscope and observe under low and high power

Compare different types of hair under the microscope

The medulla is not always present and may not be seen in some hair. When carrying out whole mount, students will have the opportunity to compare different hair strands, study the characteristics of the medulla (fragmented, continuous etc) and determine whether it is missing altogether.

Under the compound microscope, students will view scales on the surface as irregular annular patterns which tend to be different in appearance when compared with that of animal hair. On the other hand, a whole mount will show the medulla part of the hair as either broken (fragmented), continuous or absent.

Conclusion

Observing hair under the microscope (both stereo and compound microscope) can be and easy, fun activity for students. The students get an opportunity to view and study different types of hair and be in a position to identify hair based on its structure.

For instance, through experience, a student will be able to differentiate between human and animal hair as well as determine whether given hair is healthy or mistreated.

Related: Spider Web Under the Microscope, Cheek Cells Under the Microscope and Sugar Crystals too.

Interesting read: Comparison Microscope - Mainstay of Forensics

Return to Microscope Experiments Main Page

Return from Hair Under the Microscope to MicroscopeMaster Research Home

Bisbing, R. E. Forensic identification and association of human hair. In: Forensic Science Handbook. Vol. 1, 2nd ed., R. Saferstein, ed. Pearson Education, Upper Saddle River, New Jersey, 2002.

Forensic Human Hair Examination Guidelines. Scientific Working Group on Materials Analysis (SWGMAT. April 2005.)

Lavker RM, Bertolini AP, Freedberg IM et al. Biology of hair follicles. In: Freedberg IM et al (eds.). Fitzpatrick's Dermatology in General Medicine, 5th ed. New York: McGraw-Hill; 1999:230-238.

Leon Augustus Hausman, and Cornell University. Human Hair Under the Microscope Recent Acquisitions to the Knowledge of Its Minute Structure, and Their Applications. 1922.

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Hair Under the Microscope - Compound and Stereo Microscope Observations

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Our hair grows from follicles located under the skin and has two main parts. Part of the hair that remains under the skin inside the follicle is referred to as the root while the part that protrudes to the surface (head, arms etc) is known as the shaft.

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Visible Proofs: Forensic Views of the Body: Resources: Web Links

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Visible Proofs: Forensic Views of the Body: Resources: Web Links

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K-12 activities

The Case for Innocence is the companion Web site to a similarly-titled episode of the PBS series, Frontline. It explains the science behind DNA testing and profiles four compelling cases, during which DNA evidence had been ignored, discounted, or kept secret.
Grade Level: 9-12

CSI, The Experience: Web Adventures is an educational site developed in conjunction with the traveling exhibition, CSI, The Experience. The site offers opportunities to analyze forensic data and test one's skills in multi-level games.
Grade Level: 7-12

Ladder of Life Lesson Plan and its extensions teach students about practical applications of DNA profiling and the role that DNA profiling plays in the field of forensic science, through an in-class DNA extraction activity. This activity compliments "Killer's Trial", an installment of the television series NOVA.
Grade Level: 10-12

Wanted-Butch and Sundance is an activity in which students use forensic anthropology techniques to identify a set of remains. This activity compliments "Wanted: Butch and Sundance", a 1993 installment of the television series NOVA.
Grade Level: 6-12

What Jennifer Saw is the companion Web site to an episode of the PBS show Frontline. What Jennifer Saw examines false eyewitness identification in crimes and the role of DNA evidence in exonerating the wrongfully accused.
Grade Level: 9-12

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The Case for Innocence is the companion Web site to a similarly-titled episode of the PBS series, Frontline. It explains the science behind DNA testing and profiles four compelling cases, during which DNA evidence had been ignored, discounted, or kept secret.

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Introduction to How Crime Scene Investigation Works | HowStuffWorks

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Introduction to How Crime Scene Investigation Works | HowStuffWorks

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Advertisement

On TV shows like "CSI," viewers get to watch as investigators find and collect evidence at the scene of a crime, making blood appear as if by magic and swabbing every mouth in the vicinity. Many of us believe we have a pretty good grip on the process, and rumor has it criminals are getting a jump on the good guys using tips they pick up from these shows about forensics.

But does Hollywood get it right? Do crime scene investigators follow their DNA samples into the lab? Do they interview suspects and catch the bad guys, or is their job all about collecting physical evidence? In this article, we'll examine what really goes on when a CSI "processes a crime scene" and get a real-world view of crime scene investigation from a primary scene responder with the Colorado Bureau of Investigation.

CSI Basics

Crime scene investigation is the meeting point of science, logic and law. "Processing a crime scene" is a long, tedious process that involves purposeful documentation of the conditions at the scene and the collection of any physical evidence that could possibly illuminate what happened and point to who did it. There is no typical crime scene, there is no typical body of evidence and there is no typical investigative approach.

At any given crime scene, a CSI might collect dried blood from a windowpane - without letting his arm brush the glass in case there are any latent fingerprints there, lift hair off a victim's jacket using tweezers so he doesn't disturb the fabric enough to shake off any of the white powder (which may or may not be cocaine) in the folds of the sleeve, and use a sledge hammer to break through a wall that seems to be the point of origin for a terrible smell.

All the while, the physical evidence itself is only part of the equation. The ultimate goal is the conviction of the perpetrator of the crime. So while the CSI scrapes off the dried blood without smearing any prints, lifts several hairs without disturbing any trace evidence and smashes through a wall in the living room, he's considering all of the necessary steps to preserve the evidence in its current form, what the lab can do with this evidence in order to reconstruct the crime or identify the criminal, and the legal issues involved in making sure this evidence is admissible in court.

The investigation of a crime scene begins when the CSI unit receives a call from the police officers or detectives on the scene. The overall system works something like this:

The CSI arrives on the scene and makes sure it is secure. She does an initial walk-through to get an overall feel for the crime scene, finds out if anyone moved anything before she arrived, and generates initial theories based on visual examination. She makes note of potential evidence. At this point, she touches nothing.

The CSI thoroughly documents the scene by taking photographs and drawing sketches during a second walk-through. Sometimes, the documentation stage includes a video walk-through, as well. She documents the scene as a whole and documents anything she has identified as evidence. She still touches nothing.

Now it's time to touch stuff - very, very carefully. The CSI systematically makes her way through the scene collecting all potential evidence, tagging it, logging it and packaging it so it remains intact on its way to the lab. Depending on the task breakdown of the CSI unit she works for and her areas of expertise, she may or may not analyze the evidence in the lab.

The crime lab processes all of the evidence the CSI collected at the crime scene. When the lab results are in, they go to the lead detective on the case.

Every CSI unit handles the division between field work and lab work differently. What goes on at the crime scene is called crime scene investigation (or crime scene analysis), and what goes on in the laboratory is called forensic science. Not all CSIs are forensic scientists. Some CSIs only work in the field - they collect the evidence and then pass it to the forensics lab. In this case, the CSI must still possess a good understanding of forensic science in order to recognize the specific value of various types of evidence in the field. But in many cases, these jobs overlap.

Joe Clayton is a primary crime scene responder at the Colorado Bureau of Investigation (CBI). He has 14 years of field experience and also is an expert in certain areas of forensic science. As Clayton explains, his role in laboratory analysis varies according to the type of evidence he brings back from the crime scene:

Crime scene investigation is a massive undertaking. Let's start at the beginning: scene recognition.

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Advertisement ­On TV shows like "CSI," viewers get to watch as investigators find and collect evidence at the scene of a crime, making blood appear as if by magic and swabbing every mouth in the vicinity­.

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A Guide for Explosion and Bombing Scene Investigation

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A Guide for Explosion and Bombing Scene Investigation

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Forensic Science Technician Job Description: Salary, Skills, & More

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Forensic Science Technician Job Description: Salary, Skills, & More

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Forensic science technicians work with law enforcement to analyze evidence and investigate crimes. They also work with crime scene investigators, who provide them with evidence that requires analysis in a laboratory setting. The evidence gathered from crime scenes may include fingerprints, blood, hair, bullet fragments, photographs, and more. While forensic science technicians should have a working knowledge of law enforcement, their background typically is in biology, chemistry, and other scientific fields.

Forensic Scientist Duties & Responsibilities

Forensic scientists are required to handle the following work:

Collaborate with crime scene investigators

Handle crime scene evidence

Classify and organize evidence

Analyze evidence

Report findings

Document findings

Testify in court

Forensic science technicians do their work in a laboratory setting for the most part. Police and crime scene investigators gather evidence that they bring to forensic science technicians to have analyzed. Because of the nature of the work, forensic science technicians need to be detail-oriented and organized, making sure evidence is in no way tainted or mishandled in any way that can raise questions about its validity.

It sometimes is necessary for forensic science technicians to testify in court about their findings in order to explain them in a way that a judge or jury can understand. They may even have to defend their methodology or conclusions.

Forensic Scientist Salary

Salaries for forensic science technicians can vary widely depending on where they work, as well as how much experience they have.

Median Annual Salary: $57,850

Top 10% Annual Salary: $95,600

Bottom 10% Annual Salary: $33,880

Education, Training, & Certification

A strong background in science is necessary to become a forensic science technician. A degree in forensic science is preferable as a starting point for this career, but degrees in biology, chemistry, or other related fields also can serve as entry points to becoming a forensic science technician. A broad range of classwork will be beneficial as training for the job, and professionals who obtain advanced degrees in relevant sciences may advance further in the profession.

Biology: A broad knowledge of biology is necessary, including microbiology, molecular biology, and cell biology.

Chemistry: A strong foundation in chemistry also is necessary, especially in the areas of biochemistry and organic chemistry.

Forensic Pathology: Even schools that do not offer degree programs in forensic science often offer courses specific to the field.

Other Relevant Courses: Students also should study genetics, toxicology, calculus, statistics, and criminology courses to help build a strong foundation for getting into a career as a forensic science technician.

Forensic Scientist Skills & Competencies

While scientific knowledge and analytical skills are important for forensic science technicians, there also are other skills necessary to be good at the job:

Communication: Forensic science technicians must have excellent speaking and writing skills in order to share information with colleagues and present findings in court. They also need to collaborate well with crime scene investigators and other law enforcement officers.

Problem Solving: Using scientific methods to solve problems and connect different puzzle pieces from a crime scene is the bulk of the job. Rarely will conclusions be obvious, and forensic science technicians need to work through evidence meticulously.

Critical Thinking: Forensic science technicians need to question everything and eliminate all other possibilities before reaching conclusions.

Attention to Detail: Examining evidence requires the ability to notice minute details and subtle differences. As well, the handling and cataloging of evidence must be done following precise procedures so no evidence can be questioned due to it being mishandled.

Job Outlook

Increases in technology and the reliability of forensic evidence is expected to increase demand for forensic science technicians, and the U.S. Bureau of Labor Statistics projects about 17 percent job growth in the field for the decade ending in 2026. This is more than twice the rate of growth projected for all jobs combined.

Work Environment

Forensic science technicians work mostly in a lab setting analyzing evidence collected by investigators. Forensic science technicians need to have a good rapport with crime scene investigators and other law enforcement officers who gather evidence. It's not uncommon for forensic science technicians to be called to testify as witnesses in criminal cases in order to explain their findings.

In addition to working in police laboratories, forensic science technicians might work with coroners or in morgues.

Work Schedule

Hours tend to be standard business hours, but there can be times when work needs to be expedited, resulting in evening or weekend hours.

How to Get the Job
SCIENTIFIC APTITUDE
It's important to have a passion for science and research.
STUDY FORENSIC SCIENCE
An undergraduate degree in forensic science is not always mandatory, but it is helpful.
GAIN EXPERIENCE
Seek internships or lab assistant positions in police laboratories, coroners' offices, or other similar settings.

Comparing Similar Jobs

The skills necessary to be a forensic science technician translate well to many careers in science. Here are a few different career paths along with median annual salaries:

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Forensic Science Technician Job Description: Salary, Skills, & More

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Forensic science technicians work with law enforcement to analyze evidence and investigate crimes. They also work with crime scene investigators, who provide them with evidence that requires analysis in a laboratory setting. The evidence gathered from crime scenes may include fingerprints, blood, hair, bullet fragments, photographs, and more.

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The Crime Analyst's Blog: Introduction to Link Analysis: Part 3 Link Analysis Diagraming

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The Crime Analyst's Blog: Introduction to Link Analysis: Part 3 Link Analysis Diagraming

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I originally wrote this post for a software company's blog in 2014. This company was bought out and recently their blog and website have been removed from the web permanently. I am reposting it here for posterity.

Two weeks ago I started a series of posts on Link Analysis. Link Analysis diagrams are used to explain the relationships between entities in a criminal investigation. There are three main types of diagrams that are part of Link Analysis. They are:

Time Event Chart

Association / Activity Matrix

Link Analysis Diagram

In this final post in the series, we're going to look at the last type of diagram, the Link Analysis Diagram. All the other diagrams build toward a Link Analysis Diagram.
Seven Steps of Link Analysis
Anacapa Sciences Inc. is one of the most well known groups teaching Criminal Intelligence Analysis to law enforcement in the United States. In their instruction they list Seven Steps of Link Analysis.

They are:

1. Assemble all raw data

2. Determine the focus of the chart

3. Code an association matrix

4. Code the associations in the matrix

5. Determine the number of links for each entity

6. Draw the preliminary chart

7. Clarify and re-plot the chart

Time Event Charts, Association and Activity Matrixes are important to construct prior to constructing a Link Analysis Diagram. The analysis of the Time Event Chart, and matrixes will assist you in ensuring that your Link Analysis Diagram is accurate and complete.
Link Analysis Diagramming
While an Association Matrix indicates that a relationship exists between two or more persons, Link Analysis diagramming shows you what that relationship is.

Since your Link Analysis diagram may be seen by many persons it is important that your diagram conforms to certain established conventions. The US Army Intelligence Center describes it this way: "Standardization is critical to ensuring that everyone constructing, using and reading a link diagram understands exactly what the diagram depicts." Your charts and diagrams are supposed to make things easier to understand, not harder!

Persons are depicted by an open circle with their name or alias inside.

Persons with an alias are depicted by overlapping circles with their name in one and the alias in the other.

Entities or events are depicted by a square or rectangle with the entity name inside.

A known link between two persons is represented by a solid line connecting the two.

A suspected link between two persons is represented by a dashed line connecting the two.

Conveyances are represented by a triangle.

Displaying a person's membership in an entity is done by placing the person symbol in the entity symbol. (Since the person is inside the entity, the relationship is assumed and there is no need for a line linking the two.)

A person can be a member of more than one entity.

A person can be associated with an entity but not a member of that entity.

If Jones was associated directly with Smith and not just the Mongols, you could extend the line to Smith.

If Jones was known to be associated with the Mongols, and was believed to be associated with Smith you could display that like this:

As your chart grows you should avoid crossed association lines wherever possible.

Instead rearrange your chart elements. If there is no other way, display the lines like this:

You can depict past membership in an organization. If Smith is the current president of the Mongols, and Davis is the former president you could depict it like this. This would also work if Davis' membership was suspected and not known.

Here's what a completed Link Analysis chart looks like.

This chart was from an actual bank robbery conspiracy that I worked on. Any idea who the main actor was?

Methods To Create Charts
There are a number of methods you can use to create the various Link Analysis charts. Each of these methods has its strengths and weaknesses. They are:

Pencil and paper

Generalized computer drawing applications

Specialized Link Analysis software

The first method, pencil and paper, has the advantage of having nearly no learning curve to operate. It's also supremely portable and there is a very strong possibility that your organization already possesses them so the impact to your budget is minimal. The downside is that rearranging the elements on your chart is messy and time consuming. A drafting circle template or flowchart template can make your drawings much neater.
The second method is my favorite. Drawing programs can be found on most computers and range from limited functionality programs such as Paintbrush to full blown professional grade CAD or drawing programs. One that nearly every police agency possesses is Microsoft Office. MS Office's tools have drawing tools and probably the easiest way to utilize them is by using PowerPoint. The line tool will also snap to points on the shapes and stay connected. This helps when rearranging objects on the page as the lines will stay connected to the shape while you rearrange your chart. Those same drawing tools are also available in Word though the commands to access them are a bit buried in Word's UI.

The last method is using specialized link analysis software such as i2 or RFFlow. These applications are great in that they are specifically designed for link analysis however; they can be costly and have somewhat steep learning curve to get good results.

As was stated in the Introduction, "Don't let the tools drive the problem". The method you use is not as important as the chart you create. A messy but accurate pencil chart beats a neat, computer generated but inaccurate chart hands down.

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Introduction to Link Analysis: Part 3 Link Analysis Diagraming

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I originally wrote this post for a software company's blog in 2014. This company was bought out and recently their blog and website have been removed from the web permanently. I am reposting it here for posterity. Two weeks ago I started a series of posts on Link Analysis.

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Pick your topic:

All or some of the projects listed were fully or partially funded through grants from the Bureau of Justice Assistance, the National Institute of Justice, the Office of Juvenile Justice and Delinquency Prevention, Office of Justice Programs, and/or the US Dept. of Justice. Neither the US Dept. of Justice nor any of its components operate, control, are responsible for, or necessarily endorse this website (including, without limitation, its content, technical infrastructure, and policies, and any services or tools provided).

This website produced by the National Forensic Science Technology Center. Unless otherwise attributed, contents of this site are copyrighted by NFSTC. To request permission to use any portion of this work, please email the request to info@nfstc.org, indicating the material being requested, as well as how and when it would be used.

To cite this website as a resource, select a format below. Include the link to the module you are citing and the date accessed:

MLA: NFSTC. "A Simplified Guide to Crime Scene Investigation" LINK HERE National Forensic Science Technology Center, September 2013. (Accessed DATE)

PLTW, In-text: (NFSTC, 2013)

PLTW, End: National Forensic Science Technology Center. 2013. Forensic Science Simplified [Internet] USA. [Accessed YEAR MO DAY] Available from: http://ADD LINK HERE

Find out more about this project.

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All or some of the projects listed were fully or partially funded through grants from the Bureau of Justice Assistance, the National Institute of Justice, the Office of Juvenile Justice and Delinquency Prevention, Office of Justice Programs, and/or the US Dept. of Justice. Neither the US Dept.

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Crime Figures: Famous Criminals, Murderers & Victims | Biography.com - Biography

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Crime Figures: Famous Criminals, Murderers & Victims | Biography.com - Biography

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Criminals and crime figures remind us of the darker side of human society. From crooks like Al Capone and Bonnie and Clyde to murderers such as Jeffrey Dahmer

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Rookie Year: The Engineering Intern's Toolbox (Part 2)
A Series of Technical Blogs for Engineering Interns & Entry-Level Engineers
" What on earth is that thing?" asks everyone who sees a micrometer for the first time. Who can blame them as it looks like something from a medieval torture chamber. And it's just as tricky to operate. " This thing takes three hands... and the numbers make no sense!" So, why then does every veteran machinist swear that a micrometer is the best tool in their toolbox?

A micrometer is a simple and precise way to take a measurement using a hand tool. It can easily and reliably measure objects to within 0.001 inches. Despite all of your negative thoughts, every engineer and machinist gets introduced to the micrometer. Often knowing how to useone is something most companies expect interns to already understand. Here's a quick lesson on micrometers to help you stay ahead of the class.

A micrometer is a highly precise device for measuring various objects. It operates by measuring the space between a hard stop (anvil) and a movable surface (spindle). When a thimble is turned it drives the spindle closer or farther away from the anvil. To take a measurement an object is placed between the anvil and the spindle and the thimble is spun until the object is gently pinched between the two faces. After the object is pinched the scale is read and a decimal measurment is derived. *For example, 0.165 inches or 4.19 mm

The basic anatomy of a micrometer is very simple. The frame of the micrometer houses all of the components that don't move relative to the spindle. This includes the anvil, lock nut, and the sleeve. The anvil is a precision ground flat surface that acts as a reference. The lock nut is simply a quarter turn nut that locks the spindle from turning. The sleeve contains the scale which is used to determine the measurement and the internal threads which allow the spindle to move.

The moving parts consist of the spindle, thimble, and ratchet. Like the anvil the spindle contains a precision ground measuring face on the flat of the cylinder. The thimble acts like the head of a bolt. When you rotate the head it drives the bolt forward or backward. The Ratchet is a mechanism to insure that the spindle does not pinch the object too tightly leading to a false reading.
Quick tips:
How you hold and use a micrometer will instantly tip a veteran off as to whether you know or don't know what you are doing. Rookies typically need a third hand and excessively fumble around in order to take a measurement. An old pro can use a micrometer in one hand and hold the item to be measured in the other, see Figure 3. The proper way to use a micrometer is to hold it in your dominant hand. Grasp the thimble between your thumb and index fingers. Place the C-shape of the frame against your palm. Finally, partially wrap your pinky or ring finger within the inside of the frame. Hold the object to be measured in your non dominant hand.

Support the weight of the micrometer in your palm so you can twist the thimble or ratchet by rubbing your thumb and index fingers.

Don't insert your pinky or ring finger into the frame so much that you obstruct the object to be measured.

Don't cover the sleeve with your palm or you won't be able to see the measurement.

Engraved on the micrometer's sleeve is a scale. This scale contains a long line the runs the entire length of the micrometer's sleeve (datum line). In Figure 4 this line is highlighted in yellow. The numbers on the scale correspond with how far away the spindle is from the anvil. The zero on the scale corresponds with the spindle touching the anvil (ie: zero distance between the surfaces). A micrometer is usually set up for either English or metric units only. On English micrometers each dash on this scale represents .025² (25 thousandths of an inch). The large numbers represent .100² (100 thousandths of an inch).

The spindle also contains a scale along its circumference, each of these lines are highlighted in green in Figure 4. Each line on this scale represents .001² (1 thousandth of an inch). There are 25 of these lines along the spindle. As the spindle revolves it will reveal more or less of the datum line. One revolution of the spindle corresponds to .025² or one line on the datum line. Therefore, one revolution of the spindle will either reveal or hide one dash on the datum line.

To take a measurement on the micrometer the object is gently pinched between the anvil and spindle. Once a very gentle pinch has occurred the user twists the ratchet until it clicks once or twice. This insures that the right amount of tension is applied. The object should be held firm enough to not fall out of the micrometer under its own weight yet gently enough that it can easily slip away if grasped. If necessary the user can apply the lock nut to prevent the spindle from tightening or loosening while interpreting the measurement.
To interpret the measurement requires some mental math:
The user then looks at the lines on the spindle and finds which markings are aligned with the datum line. This line, highlighted with the red arrow in Figure 4, is the measurement.

1. Read the largest number shown on the datum line. In Figure 4, the 3 is still visible. This corresponds to .300 inches.

2. Count the number of dashes on the datum line between the last large number and the spindle. In Figure 4, 1 line is visible and represents .025 inches.

3. Read the number on the spindle that is aligned with the datum line. This is the line highlighted with the red arrow. As each line is equal to .001² the highlighted line in the picture is read as .016²

4. Lastly add these three numbers together to get the final measurement:

Example: .300² + .025² + .016² = .341²

Written By: Sean Derrick - Product Development Engineer |
Sean has a B.S. in Engineering Design and a M.S. in Manufacturing Engineering from Western Michigan University. He has over 7 years of product development experience in a variety of industries ranging from medical, automotive, furniture, consumer products, and defense. Sean enjoys hiking, mountaineering, skiing, movies, and is pursuing a Ph.D in his free time.

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Rookie Year: The Engineering Intern's Toolbox (Part 2) A Series of Technical Blogs for Engineering Interns & Entry-Level Engineers"What on earth is that thing?" asks everyone who sees a micrometer for the first time. Who can blame them as it looks like something from a medieval torture chamber.

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Gale offers a variety resources for education, lifelong learning, and academic research. Whether you are looking for peer-reviewed articles; full-text magazines, newspapers, and eBooks; primary source documents; and videos or podcasts, Gale puts the right vetted content and tools at your fingertips!

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Gale offers a variety resources for education, lifelong learning, and academic research. Whether you are looking for peer-reviewed articles; full-text magazines, newspapers, and eBooks; primary source documents; and videos or podcasts, Gale puts the right vetted content and tools at your fingertips!

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BCI Science School - Ohio Attorney General Dave Yost

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BCI Science School - Ohio Attorney General Dave Yost

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Welcome to the Bureau of Criminal Investigation's BCI Science School!

BCI Science School (BCISS) was created so students could learn about the fields of forensic science and criminal investigations, and related careers. These fields rely heavily on the STEAM (Science, Technology, Engineering, the Arts, and Mathematics) disciplines, and our goal is to make these disciplines exciting and engaging for students at an early age.

With a STEAM-based curriculum, BCI Science School includes 26 lesson plans for fourth graders, using hands-on experiments and inquiry-based learning to help solve fictional crimes. The interdisciplinary curriculum focuses specifically on the Ohio Department of Education (ODE) fourth grade standards. Most lesson plans include short videos of BCI forensic scientists and BCI special agents (investigators), which allow us to "take" students into the laboratory and into the field.

The curriculum uses supplies and materials that should be readily accessible or easy to obtain at your school or home. Lessons that require supplies that may be more expensive or difficult to find are marked as optional.

The implementation schedule of the curriculum can be modified to take a classroom's structure, resources, and student needs into account. For example, some teachers complete one lesson every day and some teachers opt for one lesson every week. While the curriculum was developed for the fourth grade classroom environment, BCI Science School could easily be adapted for after-school programs, summer camps, and homeschool settings.

We hope that students become excited about science, technology, engineering, arts, and mathematics with our curriculum and that they are exposed to potential careers and opportunities to pursue in the future!

The entire curriculum is accessible on the left-hand side of this page.

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Welcome to the Bureau of Criminal Investigation's BCI Science School! BCI Science School (BCISS) was created so students could learn about the fields of forensic science and criminal investigations, and related careers. These fields rely heavily on the STEAM (Science, Technology, Engineering, the Arts, and Mathematics) disciplines, and our goal is to make these disciplines exciting and engaging for students at an early age.

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News | On the Scene and in the Lab - Forensic®

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News is designed for forensic professionals and digital forensic investigators | forensicmag.com

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These freaky crime-predicting tools are eerily reminiscent of Minority Report

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These freaky crime-predicting tools are eerily reminiscent of Minority Report

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Connor Deleire was sitting alone in a friend's car in Manchester, New Hampshire, one late October afternoon in 2015 when the police zeroed in on him. The 18-year-old waited near the intersection of Union and Merrimack Streets as the friend left to pick up his niece a block away. What Deleire didn't know was that the vehicle was parked in a "predictive hot spot," an area determined by a computer algorithm used by the Manchester Police Department to be the likely scene of a crime.

Just being in the area was enough to arouse suspicion, officials at the time said. Then, according to police, Deleire failed to give a "legitimate" reason for being there and grew increasingly agitated with officers. The result of that confrontation: Deleire had his head bashed into a cop cruiser, his body zapped with a stun gun, and his face blasted with pepper spray. The beatdown landed him in the hospital with a concussion, his father John Deleire told Vocativ in a recent interview.

In the end, the only crime his son was charged with was resisting arrest.

What you get when parked in a "predictive hot spot." Soon to be most of USA #americawakeup https://t.co/D5ml92JMpE pic.twitter.com/MeGmCFyso4

- sorrowandpain (@sorrowandpain) October 24, 2015

"If you're in a predictive hot spot, you're going to be accused of committing a crime even if you're in broad daylight and have a reason to be there," said John Deleire, an attorney who said his family had a long history of law enforcement service in New England. "I think it was the predictive policing part of this that caused this whole thing to happen."

According to the National Institute of Justice, predictive policing refers to "any policing strategy or tactic that develops and uses information and advanced analysis to inform forward-thinking crime prevention." These policing strategies usually involve mathematical or algorithmic techniques designed to predict crimes as well as who will commit or be victimized by them.

The Connor Deleire incident underscores the swelling fear among civil liberties groups, who see the rise of predictive policing as further enabling the worst tactics and practices of law enforcement. But even as the crime-fighting technology stirs controversy, police forces are flocking to it. Once the stuff of sci-fi books and Hollywood blockbusters, predictive analytics continues to entice law enforcement agencies, big and small, throughout the United States.

"The 'Minority Report' of 2002 is the reality of today," declared former New York City Police Commissioner William Bratton in 2015, referring to Steven Spielberg's film in which cops round up killers before they can carry out their heinous crimes.

(Courtesy Vocativ)

For decades cops have turned to technology to target would-be criminals and zero in on where they strike. Computers began crunching stats and churning out crime maps while Ronald Reagan was still in the White House. Bratton himself revolutionized American policing in the early 1990s through CompStat, a data-driven tool credited with driving down crime.

The latest breakthrough came around 2010 when police departments - with the help of U.S. Justice Department funding - began experimenting with the same type of software that Google uses to rank websites in their search engines. Using historical crime data and other variables, they created algorithms geared to forecast where and when crime will occur, and who its perpetrators and victims might be.

The prospect of stopping crime before it happens is all too alluring. At least 20 of the nation's 50 largest police forces - including Los Angeles, New York, and Philadelphia - now use predictive analytics, one study found last year. Smaller departments, from Fort Meyers, Florida, to Santa Cruz, California, also rely on these crime-fighting algorithms to deploy officers and resources.

"The seduction of technology, of doing more with less and with fewer resources, is just too good pass up," said Andrew Ferguson, a law professor at the University of the District Columbia and author of the forthcoming book, The Rise of Big Data Policing: Surveillance, Race, and the Future of Law Enforcement.

With few exceptions, departments that have integrated predictive analytics into their police work claim they've seen striking results. Manchester police credited the city's 25 percent drop in the number of property crimes committed in 2016 to the the very software that helped turn Connor Deleire into a target the year before. Nick Willard, Manchester's police chief, has been so gung-ho about predictive policing's potential that he has appeared in at least two promotional videos for the company that created his department's technology. He did not reply to Vocativ's request for comment.

Cops in Chicago, meanwhile, believe that predictive policing could be used to combat the city's sweeping homicide epidemic. Four years ago the Chicago Police Department designed an algorithm using variables such as arrest records and gang affiliations to forecast who is most likely to be involved in gun violence. The department then began to place these potential perpetrators and victims on a secret "heat list" used by its personnel. Last May, Chicago police said that three out of four shooting victims in 2016 had been on the list, as were four out of five people arrested for shootings.

Yet the actual efficacy of these crime-fighting algorithms remains largely unproven. The small body of independent research on predictive policing, in fact, appears to challenge some of the claims made by law enforcement. A RAND Corporation study from 2014 tested a predictive policing model aimed at reducing property crime in Shreveport, Louisiana, and found no evidence that it did so. In a different report released last year, RAND found that people on a 2013 version of Chicago's heat list were "not more or less likely to become a victim of a homicide or shooting than" a control group its authors looked at.

"It's definitely not a magic bullet," said David Robinson, whose technology-focused think tank Upturn published a wide-ranging survey on predictive policing in the U.S. last year. "The actual independent evidence suggests these systems might not make people any safer."

Just as troubling for an array of civil liberties and civil rights advocates is the belief that predictive analytics - which relies heavily on crime data and other variables traditionally used by law enforcement - may simply reinforce police bias toward poor and minority communities while undermining the constitutional rights of individuals. The ACLU and 16 other groups recently outlined these concerns in a searing rebuke on predictive policing.

"The data driving predictive enforcement activities - such as the location and timing of previously reported crimes, or patterns of community- and officer-initiated 911 calls - is profoundly limited and biased," wrote the coalition, which also included the NAACP, The Center for Democracy and Technology, and the Brennan Center for Justice. "Systems that are engineered to support the status quo have no place in American policing."

The use of predictive analytics by law enforcement, however, is not expected to slow any time soon. Police in Mesa, Arizona, just started a 3-year, $170,000 pilot program using predictive policing software. Cops from east Texas to Florida's panhandle are now gearing up to implement crime-fighting algorithms of their own.

Just what will happen in these communities remains to be seen. For Connor Deleire's father, his son's story remains a painful reminder of what can go wrong. "[Connor] grew up in a police family and what happened to him pretty much shattered all of his ideals," John Deleire said. "It left him with a bad taste. It left all of us with a bad taste."

The new season of DARK NET - an eight-part docuseries developed and produced by Vocativ - airs Thursdays at 10 p.m. ET/PT on SHOWTIME.

This article originally appeared at Vocativ.com: This teen's story is your worst 'predictive policing' nightmare.

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These freaky crime-predicting tools are eerily reminiscent of Minority Report

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Connor Deleire was sitting alone in a friend's car in Manchester, New Hampshire, one late October afternoon in 2015 when the police zeroed in on him. The 18-year-old waited near the intersection of Union and Merrimack Streets as the friend left to pick up his niece a block away.

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Truth, Beauty, Science. - Undark Magazine

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Truth, Beauty, Science. - Undark Magazine

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Truth, Beauty, Science. - Undark Magazine

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Undark Magazine explores science at the point where it intersects - and sometimes collides - with politics, economics and culture.

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Attention all teachers, students, or even just the curious--we have a variety of fun, interesting, and education activites free for the download. Click here to see how bone length can be used to calculate height, create your own bill for forensic testing, or solve forensic logic problems--and more!

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Autopsy findings are combined with the results of other investigations, including the microscopic examination of organs and tissues removed at autopsy, toxicological analyses (of blood and urine, for example), and correlated with the available clinical or medical history of the deceased, as well as the circumstances of their death, in order to answer questions relating to their death.

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Scanning Electron Microscopy and X-Ray Microanalysis for Chemical and Morphological Characterisation of the Inorganic Component of Gunshot Residue: Selected Problems

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Scanning Electron Microscopy and X-Ray Microanalysis for Chemical and Morphological Characterisation of the Inorganic Component of Gunshot Residue: Selected Problems

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1. Introduction

Inorganic components of gunshot residue (GSR), in particular, metallic particles originating from the ammunition primer, reveal characteristic properties and so provide themselves a high value evidence of using a firearm. Only few particles, of total mass no greater than 100 picograms, can be accepted as the evidence relating an individual with a shooting incident. The fundamental criterion of the identification of metallic gunshot particles is their chemical contents, that is, rarely occurring set of elements: lead, antimony, and barium as well as their morphology reflecting the kinetics of the processes undergoing during a gunshot, especially rapid cooling of droplets of the molten metals present in the expanding plum of products of the primer detonation and the propellant combustion.

As reported and reviewed by many, see, for example, Dalby et al. [ 1], formal classification scheme for gunshot particles being worked out and applied by the experts in Western Europe and USA since about 1980 on the basis of the experiences with traditional ammunition embraced a division into unique and indicative particles. Particles simultaneously containing lead, antimony, and barium (Pb-Sb-Ba) were classified into unique ones allowing stating, categorically, that they originated from a firearm discharge. Particles containing two- or one-component combinations of these elements (Pb-Sb, Pb-Ba, Sb-Ba, Pb, Sb, and Ba) as well as the ones containing barium, calcium, and silicon (Ba-Ca-Si) were classified into the class of indicative particles that enable one to infer on their origin from a firearm discharge with a high probability. However, since about 2003, experts resigned from the terms unique and indicative for the benefit of characteristic and consistent with gunshot residue, taking into account the publication of Torre et al. [ 2], who demonstrated the presence of a single particle containing lead, antimony, and barium and revealing an oval shape that resembled the morphology of GSR, however, originating from car brake pads. Thus, nowadays, one cannot identify a gunshot particle with certainty but with a high probability, similarly as any other material being a criminalistic microtrace. Nevertheless, the three-component particles, especially when numerously occurring in a sample, provide themselves a high value evidence of a gunshot. Establishing the presence of gunshot residue in the sample collected from hands or clothing of a person allows relating the person with a high or very high probability, either with shooting or being in the nearest vicinity of a firing gun or else getting in contact with an object highly contaminated with GSR.

Questions directed to a forensic chemist by the practitioners of administration of justice concerned also established the type of ammunition considering GSR particles as the only evidence being accessible for investigations. Despite the cliché that chemical analysis of GSR does not contribute to establishing the type of ammunition they originate from, the initial results of research on the chemical composition of GSR originating from ammunition by Mesko Metal Works, Skarżysko-Kamienna, Poland, revealed lack of particles containing, simultaneously, lead, antimony, and barium [ 3]. That demonstrated that chemical composition of the primer in this ammunition differed from chemical composition of primers in ammunition present on the market in other countries. This lead the author to the conclusion that the formal scheme of classification of GSR and so the system of the evaluation of the evidence might be inadequate for preparing reliable expert's reports and inspired to perform further research in this field of science.

The discrepancy between formal classification scheme of GSR and the possibility of detection of particles originating from ammunition primer types that are different from the traditional ones was also noticed by Romolo and Margot [ 4]. They proposed another individual attempt to the evaluation of the evidential value of metallic particles based on the mutual consistency of particles found in the items of certain case, called case-to-case approach, rather than comparing them with the arbitrary classification scheme. The majority of works published earlier concerned only the identification of lead, antimony, and barium particles and so the statement whether these particles are present in the studied material and whether they are distinguishable from particles of similar chemical contents but originating from different sources than a firearm discharge.

Further important questions concerned the possibility of establishing the mutual position of persons taking part in a shooting incident and so the reconstruction of the incident taking into account the chemical examination of the revealed gunshot residues. However, the first publications on the expansion of gunshot residue and the possible range of distance they may reach starting from the gun muzzle presented visual assessment of the gaseous plum photographed by means of a high speed camera [ 5]. Later publications focused solely on the numbers of metallic particles and neglected the chemical aspect of their dispersion [ 6, 7].

From the literature review and the research experiences with the application of the SEM-EDX, the author found that this analytical method could be utilized far more comprehensively than until now and so undertook research aiming not only at the identification of GSR but also towards understanding the relationships between their chemical and morphological properties and their source as well as the mechanisms of their formation and dissipation in the environment. The main aims of the research embraced the following: (i) a group identification of the ammunition type from the examinations of GSR with and without the comparative material from the cartridge case, (ii) dispersion of GSR in time and space (in the nearest vicinity of the shooting gun) for establishing the persistence of particles, shooting range, and possibly the mutual positions of the participants of a shooting incident, and also (iii) the obtainment of data on the prevalence of GSR in various professional environments for the assessment and possibly elimination of the risk of contamination with GSR.

2. Materials and Methods

The subjects of the study were inorganic components of the gunshot residue obtained with discharge of selected brands of ammunition suitable for popular firearm of calibres 5.6, 6.35, 7.62, 7.65, and 9 mm. Specimens were collected from various substrates, mainly hands, face, hair, and clothing of shooting and nonshooting persons within a screening research.

The study embraced the chemical composition and the morphological features of metallic particles that are dispersed in the space and time after the use of a firearm. The research was based on thorough working out of the methodology of chemical analysis of GSR particles by means of SEM-EDX technique and the interpretation of the obtained results with the use of statistical methods. An initial study concerned the evaluation of the repeatability of the measurement process and its usefulness in comparison with the manual search. The worked out research procedure is multistage including the collection and preparation of specimens, the measurement procedure, and the representation of the collected data in the form being usable for mathematical and statistical evaluation [ 3, 8].

2.1. Specimen Collection and Preparation

The preparation of the material embraced firstly the collection of a representative sample of microtraces as well as their concentration by means of multiple pressing of a SEM stub with adhesive tabs to a surface of interest. Aluminium stubs with adhesive carbon tabs by TAAB Laboratories Equipment Ltd., Berks, UK, were used. About 100 dubbings to the surfaces of interest were made with each stub. The collected specimens were covered with a conductive graphite layer using a SCD 050 sputter, BAL-TECH, Lichtenstein, and a carbon thread (TAAB Laboratories Equipment Ltd, Berks, UK) to prevent the electric charging of nonconductive particles of materials, such as fragments of epidermis, hair, and textile fibres, that usually accompany the metallic particles of interest being collected from various substrates. This way the electric conductivity is being assured to obtain electron images as well the X-ray spectra of good quality. It also prevents accumulating of thermal energy by the adhesive material, which otherwise would soften and immerse the particles, being equivalent to the loss of the evidence material. The last phenomenon was unexpectedly encountered by the author, while analysing for few hours an uncovered specimen with GSR particles that gradually swamped and soon were not detectable. This was similar to the observed softening of the adhesive material of the polymer tab under a light microscope, while preparing other materials for SEM examinations.

2.2. Working Out the Procedure of Measurement

The collected specimens were examined by means of a scanning electron microscope JSM-5800 (Jeol Ltd., Tokyo, Japan) coupled with an energy dispersive X-ray spectrometer (Link ISIS 300, Oxford Instruments Ltd., Si/Li detector, ATW-atmospheric thin window, resolution 131 eV for MnK α at 10000 counts) or with an energy dispersive X-ray spectrometer and Inca Energy Software rev. 4.09 (Oxford Instruments Ltd., High Wycombe, UK; Si/Li detector, ATW-atmospheric thin window, resolution 133 eV for MnK α at 10000 counts). The identification of GSR was performed in an automatic manner with a GunShot or an Inca Feature/GSR programme, Oxford Instruments Ltd.

The measurement process demands performing the following actions: backscattered electron images observation for the location of particles of the expected mean value of the atomic number, collection of X-ray spectrum, and observation of the morphology of each of the individual particles. In contemporary integrated SEM-EDX systems, there is a possibility of automation of a portion of the process. In such a case it embraces the phase of optimisation of the measurement parameters, the automatic search for particles, and finally the manual confirmation of the relevance of the chemical class assigned to a particle with its X-ray spectrum as well the observation of the morphology of single particles.

Location of the particles and collection and storage of their X-ray spectra and electron images by means of a manual search are time-consuming and human-engaging and so less economical than the automatic search. The advantage of the automatic method is also the repeatability of the obtained results presented as numbers of particles by means of triple measurement of the same specimen. From the inspection of the results by means of Student's t-test, it was found that the measurement is repeatable and precise [ 8]. Moreover, a comparative analysis of results obtained in both manners: automatic and manual was performed for the same specimen containing a great number of particles (). The total number of particles found manually (ca. 1500) was greater than the one found by the programme (ca. 700). However, from the investigation of the distribution of particles against various ranges of their sizes, it turned out that the observed difference resulted from the greater number of particles detected manually in the range of sizes below 1 micrometer (ca. 800), that is, below the limit of detection in the automatic run. Thus, the number of particles within the same range of sizes (ca. 700) was comparable for both methods [ 8]. This demonstrated an additional advantage of the much faster automatic search for particles.

The worked out research procedure utilising the automatic search for particles guaranteed the detection of particles of the size of at least 1 micrometer due to the appropriate choice of parameters such as the image resolution coupled with the SEM magnification, the accelerating voltage, the beam intensity, and the time of analysis of a single sample stub.

Moreover, shows that a population of GSR particles in the majority consists of particles revealing sizes of about 1 micrometer. Most of them occur isolated in the scanned area of a specimen; however, occasionally, they cluster together forming an aggregate such as the one presented in .

2.3. Methodology of Examinations of the Chemical and Morphological Properties of Populations of Particles

The next important aim of the examinations was working out a method of the analysis of the chemical composition of the whole population of particles detected in a specimen to be able to compare the populations with each other. As a result of a measurement of particular specimens, there are various numbers and various chemical classes as well as various sizes of particles obtained. The variability is a characteristic feature of GSR samples that results mainly from the dynamic conditions of their formation and dissipation as well as from the interactions with the obstacles on their way from the interior of the discharged cartridge case, where they come into being (). Much less influence reveals the environmental conditions, individual features of human skin on hands (or of the other substrates), the number of pressings of the stub against the substrate, and also the method of measurement: manual or automatic [ 3, 8].

To be able to perform comparisons between populations of the detected particles from the chemical point of view, their numbers were transformed into the form of frequencies of occurrence of particles of certain chemical class. It allowed characterizing quantitatively the chemical contents of the whole population of particles in a specimen providing a distribution of detected particles against the chemical contents. This representation of data on the chemical composition of specimens was applied in publications [ 3, 8- 14]. Similar data representation was utilised in research concerning various ranges of the effective diameters of particles as the measure of their morphology in a specimen [ 12- 14] is described later.

Results of the analysis of 135 specimens originating from that same ammunition batch-being obtained during a study on the persistence of particles on various substrates [ 14]-became an occasion for observation of a number of interesting phenomena that add to the variability of the numbers of the detected particles. One of them was an interaction of particles with the substrate resulting in braking of particle into fragments in the form of polygonal plates. Inspection into each particular plate separately usually leads to its exclusion from the population of GSR taking into account the morphological criterion. Another observed effect was merging of two or more droplets of molten materials or immersion of numerous small metallic particles (of sizes usually below 1 micrometer, i.e., below the limit of detection of the search program) in material consisting of elements of low atomic numbers, such as carbon ( Z = 6), forming one large particle of about several dozens or several hundreds of micrometers in size. In such cases the program registers a significant number of all the particles; however, it is in the gesture of the analyst to account it as one complex particle or a great number of small particles ().

It is worthwhile underlying that the total numbers of the particles detected in various specimens originating from using cartridges of the same ammunition load reveal a significant variability, whereas other parameters describing the population of detected particles demonstrate a good repeatability. This was proved while studying the distributions of particles originating from two types of 9 mm ammunition by Mesko Metal Works, Skarżysko-Kamienna, Poland, performing the analysis of variance of some parameters such as the average value of the effective diameter of particles and a parameter binding the particles diameter and their density is estimated as an arithmetic mean value of the densities of their components [ 12, 13].

Data in the form of the frequencies of occurrence of particles, in particular chemical classes, were applied in comparisons between specimens originating from the use of, physically, the same ammunition cartridge as well as between samples originating from several cartridges of the same load of ammunition. For this purpose, rang correlation tests: R-Spearman and τ-Kendall, were applied. Both tests demonstrated agreement in the chemical contents between the analysed specimens and so confirmed the correctness of the worked out and applied analytical procedures within the research of metallic particles [ 3, 8].

3. Results and Discussion

The worked out research methodology provided bases for inspection into the correlations between the chemical composition and parameters describing morphological features of the populations of particles in the dependence on various factors, such as the type of ammunition, the distance from the gun muzzle, the kind of the substrates the particles were deposited on, and the time since shooting.

3.1. The Dependence of the Chemical Contents of Particles on the Kind of Ammunition

Systematic studies of metallic particles originating from 6 popular types of ammunition: Luger 9 mm, Makarov 9 mm, (Mesko Metal Works, Skarżysko-Kamienna, Poland); Tokarev 7.62 mm, Margolin 5.6 mm (Tula Cartridge Works, Tula, Russia); Browning 6.35 mm and Browning 7.65 mm (Sellier & Bellot, Vlašim, Czech Republic), were performed [ 8]. The investigative materials were specimens collected from hands of the shooters immediately after performing the test shots. The collected specimens were examined in the automatic manner by means of the program searching for particles of the predefined features according to the previously described analytical procedure. Thus, the subjects of interest were particles containing one of the seven classes being the combination of the following chemical elements: lead, antimony, and barium and revealing sizes in the range of micrometers. The obtained results were pair-wise subjected to nonparametric test, that is, Spearman and Kendall rank correlation tests. Both of them revealed significant differences among the frequencies of occurrence of particles of particular chemical classes present in the sample of Browning 7.65 mm ammunition from these originating from all the other five examined types of ammunition demonstrating the existence of correlations between certain type of ammunition and metallic particles originating from its discharge.

For data obtained for samples collected during repetitions of test shots with the same type of ammunition (10 samples for Makarov 9 mm ammunition by Mesko Metal Works, Skarżysko-Kamienna, Poland), despite the differences in total numbers of the detected particles, there were observed similarities in proportions of the particular chemical classes of particles that were also confirmed by the application of the Spearman and Kendall rank correlations tests [ 3].

In the next stage the examinations of samples of particles obtained by repetitions of experimental shots using selected brands of ammunition (Luger 9 mm, Makarov 9 mm, Tokarev 7.62 mm and Browning 7.65 mm) were performed. The obtained results of the chemical analysis of specimens were subjected to a cluster analysis with the Ward's method that revealed clustering of the samples of GSR according to the type of ammunition they originated from [ 9, 10]. Moreover, taking into account discriminative features established by means of the Mann-Whitney test, the author proposed a classification scheme of particles originating from the four ammunition types into one of three classes. Samples originating from Makarov 9 mm and Tokarev 7.62 mm ammunition revealed a similarity and so created one cluster [ 10].

The differentiation of populations of metallic particles in the dependence on the type of ammunition, from which they originate, inspired further systematic examinations of gunshot residues originating from the same ammunition type-Luger 9 mm-of various makes and producers. 15 types of the ammunition were selected for the investigations: 8 of traditional and 7 of lead-free ones. Samples of particles were obtained for examinations using two pistols, each placed in especially constructed holder for the gun and four stubs: one placed 10 cm left from the gun near the ejector, one in front of the muzzle in the distance of 10, and two in front of the muzzle in the distance of 40 cm. The experiments were performed in two independent shooting galleries in Wiesbaden and Krakow.

The sets of specimens collected in the nearest vicinity of the gun were analyzed by means of SEM-EDX method in four laboratories using five different systems of various manufactures. The analytical results obtained for all of the selected ammunition brands of Luger 9 mm ammunition were compared with these obtained in similar manner in the other laboratories using different SEM-EDX systems. The subjects of the statistical analysis were X-ray spectra of at least one thousand particles per ammunition type but not chemical classes as in the previous studies. This attempt was selected to avoid the need of manual check of X-ray spectrum of each particle for confirmation of its chemical content and so making the study more objective. Moreover, X-ray spectra usually include characteristic X-ray lines not only of elements of the primer, but also of elements of the other parts of a cartridge, for example, copper (). The idea of taking into account the elements that are present in the cartridge case, the projectile, and the gun that remain in contact with the reacting explosives, in addition to the elements of the primer, resulted from the previous study as one of possible ways of increasing of the discrimination power of the GSR populations originating from various ammunition brands [ 10]. Since it was necessary to operate on great matrices of data (1000 of X-ray spectra × 15 kinds of ammunition × 2000 points per spectrum), data reduction was performed by means of fast Fourier transform (512 coefficients). The classification of particles into one ammunition type (one of the 15 classes) was achieved by means of the regularized discriminant analysis (RDA). The risk of a misclassification of a single particle to certain ammunition was assessed as about 10% in the model for all 15 ammunition classes and about 2% in the case of the 7 classes of lead-free ammunitions [ 15]. The obtained results were comparable for all of the applied analytical SEM-EDX systems as well as for both items of firearm that demonstrated an insignificant influence of factors other than the chemical composition of the primer on the elemental contents of the particles, as observed earlier [ 3, 8- 10]. In casework, however, the presence of material remaining inside the gun barrel after previous shots ought to be taken into account, while interpreting the detected particles [ 11].

Results of the research on differentiation of gunshot particles originating from various types of ammunition demonstrated the direct dependence of their elemental contents on the chemical composition of the ammunition primer [ 3, 8- 10, 15]. The performed examinations were also an occasion to perform a systematic review of the primer mixtures currently used by the ammunition producers. This was of great practical importance as the comprehensive information in this subject collected by Wallace was published later [ 16]. In the case of ammunition of the chemical content being different from the traditional one, based on lead, antimony, and barium compounds, the commonly accepted classification scheme of GSR may fail in lowering the evidential value of the particles and so, it should be applied with criticism. The study also demonstrated the possibility of a group identification of the residues from their chemical analysis. Although not always a population of particles can be assigned to certain ammunition type and calibre, it is possible to carry out a comparative study to either confirm or exclude whether two samples of GSR originated from the same source.

3.2. A Comparative Study of the Chemical Contents and Morphology of Airborne Particles and the Ones Remaining inside the Cartridge Case

Comparative studies of the chemical content and the morphological features of gunshot residue collected from the shooter's hands and from the interior of the cartridge case of physically the same cartridge of Luger 9 mm ammunition were performed. Four types of this ammunition representing three types of primer mixtures were chosen [ 12]. The subjects of the study were particles originating from the use of ammunition produced by Mesko Metal Works, Skarżysko-Kamienna, Poland (the primer containing mercury fulminate as the initiator, potassium chlorate as the oxidizer and antimony sulphide in the role of the fuel), Sellier & Bellot, Vlašim, Czech Republic (S&B-the primer containing lead styphnate or lead azide as the initiator, barium nitrate-the oxidizer and calcium as the fuel), as well as of the lead-free ammunition of the sintox type by Dynamit Nobel, Troisdorf, Germany (DN-containing tetrazene, diazadinitrophenol, powdered titanium and zinc peroxide). The last ammunition was used in two variants: with copper and tin jacketed projectiles.

Contrary to common opinions, it was established that there may occur significant differences in the chemical composition, both qualitative and quantitative, between the residue settled on the shooter's hands and these remaining inside the cartridge cases. Whereas in the case of using a S&B ammunition and DN with copper jacketed projectile one can observe the same qualitative chemical contents of particles settled on the shooter's hands and in the projectile, in the case of Mesko and DN with tin jacketed projectile ammunition there are present some similarities as well as significant differences both in the qualitative and quantitative chemical composition of the particles taken from the shooter's hands and the ones remaining inside the cartridge case. The elemental contents of particles present in the interior of the used cartridge case remain in agreement with the elemental contents of the primer mixture. But the elemental contents of particles leaving the gun barrel can be enriched with elements present in the projectile core (e.g., lead in the case of Mesko ammunition) or the projectile jacket (e.g., tin in the case of DN). There are also present differences in the morphological features of the compared residue (). When the process of formation of metallic particles completes in the air, they preserve their spherical shape. However, when they do not solidify before the collision, for example, with the interior walls of the cartridge case, they reveal more complex and flat shapes and also usually greater sizes. Neglecting the possible differences of particles taken from the two substrates may lead to a false differentiation of the samples and so a wrong elimination of the suspect taking part in the shooting incident.

The performed examinations allowed also drawing more general conclusions, among which the most important is that the processes of formation and propagation of particles in the cartridge case and inside the barrel proceed in one direction, which causes that the formed GSR particles originating from the primer may join and contribute fragments of the cartridge case, the core and jacket of the projectile, and also the interior walls of the barrel (together with all the impurities present there), and disperse in the surroundings of the shooting gun together with the plum of gases. The possibility of the materials-mainly metals-building the particular components of a cartridge undergoing an interaction with the reacting explosives depends on the physical and chemical properties of the appropriate metals. The correctness of the conclusion was proved in the next stage of the research on the dispersion of metallic particles in the vicinity of the shooting person.

3.3. Dispersion of the Metallic Particles in the Surroundings of a Gun

A lack of literature data on the influence of the shooting distance and the kind of the substrate, where the GSR are being collected, on the numbers, chemical composition, and morphological features of the detected particles inspired a systematic research of GSR samples obtained during test shots using two types of full metal jacket (FMJ) ammunition produced by Mesko: Makarov 9 mm and Luger 9 mm ammunition. Both kinds of ammunition were primed with the mixture based on mercury fulminate as the initiator, potassium chlorate as the oxidiser, and antimony sulphide as the fuel [ 13, 14]. Specimens were collected from targets placed in the following distances from the muzzle: 10, 20, 30, 50, 70, and 100 cm as well as from hands and clothing of the shooter, that is, from places situated in front of and behind the gun muzzle. While performing the test shots, the shooters wore cotton lab coats and the targets were covered either with cotton fabric, or cow's leather simulating popular types of clothing. The experiments were performed in such a manner that three repetitions were obtained for each point chosen in the direction of shooting and the opposite one to evaluate the repeatability of the parameters describing the populations of particles, that is, their numbers, chemical contents, and morphological features represented by the effective diameters that are being obtained by means of SEM-EDX method.

Changes of the numbers, the elemental contents, and the effective diameters of particles with the distance from the muzzle demonstrated that the distribution of particles on the shooter and his nearest vicinity is not uniform, not only from the point of view of the numbers of particles, as expected, but also from the point of view of their chemical composition and dimensions.

Whereas in the direction of shooting a relative decrease of the frequency of occurrence of lead containing particles with the increase of the distance was observed, on the shooting person, that is, in the direction opposite to shooting, a relative increase of the frequency of occurrence of lead containing particles with the increase of the distance from the muzzle took place. The frequency of occurrence of antimony particles revealed an opposite course, that is, a relative increase in the direction of shooting and a relative decrease in the opposite direction. This regularity occurred for both of the examined types of ammunition [ 13, 14]. As established from the examinations described in the previous chapter [ 12], lead is detected in the metallic particles originated from the core of the projectile.

The average values of the effective diameters of particles in samples collected from the targets and from the shooter's hands and garment increased with the increase of the distance from the muzzle. Moreover, the values of the effective diameters of particles present in samples taken from the shooter's hands were for both ammunitions significantly greater than for the sample collected from the target in the distance of 10 cm from the muzzle [ 13, 14].

It was also demonstrated that the number of particles settled on certain substrate is dependent not only on the shooting distance and the physical and chemical properties of particles but also on the material of the substrate [ 14]. Usually more particles are being settled on the cotton fabric than on the cow's leather of the popular leather jackets (). This depends on the differences in the adhesion forces acting between the metallic particles and the substrate materials. Moreover, the cotton fabric reveals a more loose structure than the leather, but much more developed surface. Fibres protruding from the threads and the surfaces of the fabric may cause the spherical metallic particle to adhere to the substrate surface in more than one point of contact. Opposite to that, the cow's leather has more compact structure and smoother surface despite of the presence of grooves.

Moreover, it was observed that less lead particles remain settled on the cow's leather than on the cotton fabric [ 14]. This state may be explained not only with the different properties of the two substrates but also with the great density of lead (11340 kg/m ³)-nearly twice as big as that of antimony (6697 kg/m ³). Among lead and antimony particles of the same sizes and similar initial velocity, lead particles reveal a greater mass and so their kinetic energy may exceed the values of energy being appropriate to be able to adhere and stay at the surface of leather substrate.

The relatively great total numbers of metallic particles revealed in samples collected from targets in the distances of about 50-100 cm, when no sooth and unburned propellant grains are being observed around the gunshot hole, enabled establishing an additional category of the shooting distance assessment taking into account physical and chemical examinations of gunshot residue pattern around gunshot hole in the target [ 14].

Analysing the obtained results, it was found that the process of formation of particles starts with the detonation of the primer and continues at further stages of the gunshot. Together with the gaseous products of the propellant deflagrating, layer by layer metallic droplets move along the walls of the cartridge case. Those of particles that are present in the head of the shock wave reach the bottom of the projectile with the open lead core and may get enriched with this element. Before the projectile is being released from the cartridge case under the growing pressure of gases, a local melting of lead in the surface layer of the core of projectile takes place and the occurring droplets and particles of lead are being pushed aside by the central stream of gases, that is, towards the edges of projectile and subsequently towards the walls of the barrel and the edges of the muzzle. In the moment, when the projectile leaves the gun muzzle, the expanding in each direction gases spread out together with the droplets of rapidly solidifying metals, mostly lead. Thus, relatively great numbers of lead particles are settled on close range targets (10-20 cm) and on the shooter, that is, his garment (in the area of arms and the upper part of the torso) [ 12- 14], as well as his face [ 17].

From the fact that within the examined metallic particles no spherical particles of copper were encountered, which would have originated from the cartridge case and the projectile jacket, but instead of this lead particles from the projectile core occurred as a result of the interaction of its bottom with the products of the reaction of the primer and the propellant, it was concluded that possible sputtering of the materials of the cartridge case and the projectile core and jacket depends on the physical properties of the constituting metals such as melting point and the specific heat. For an example, the melting point of lead equals 328°C and that of copper equals 1085°C. The specific heat (at 25°C) of lead and copper is 129 and 385 J/(kg K), respectively, which would explain the greatest susceptibility of lead to local melting and getting abstracted from the surface of the uncovered projectile core than that of copper from the cartridge case or the projectile jacket.

The differences between the elemental contents and the morphological features of particles moving into direction of shooting and these of particles moving in the opposite direction give rise to more detailed inferences on the mutual position of the persons taking part in a shooting incident.

3.4. Dispersion of the Metallic Particles in Time after Using a Firearm

Comprehensive examinations of the kinetics of the loss of GSR collected simultaneously from hands, face, and clothing of the shooter by means of the assessment of their half-life times as well as establishing the influence of the chemical composition of particles and their morphology on the process was performed [ 17]. In the examinations, Luger 9 mm ammunition by Czech factory Sellier and Bellot was used, which was primed with lead styphnate or lead azide as the initiator, barium nitrate-the oxidiser-and antimony sulphide in the role of the fuel. This ammunition has guaranteed the presence of the three-components: lead, antimony, and barium particles Pb-Sb-Ba in the investigative material. In the experiment, 5 persons took part and the test shots were performed in 9 attempts so that data were obtained for 30-minute intervals in the range of 0-4 hours. For the obtained data, being the average value of the numbers of particles revealed in 5 specimens (for 5 shooters) there were performed calculations of the half-life times of particles present on the three substrates: (i) hands, (ii) face and hair, and (iii) clothing of the shooting person. The resulting half-life time of Pb-Sb-Ba particles was about 30 minutes for hands, about 60 minutes for clothing, and about 140 minutes for the sample collected from the face and hair of the shooter. The half-life time of all particles was about 50 minutes for hands, about 60 minutes for clothing, and about 170 minutes for the sample collected from the face and hair of the shooter.

Moreover, from the inspection into the frequencies of occurrence of particles of particular chemical classes being the combinations of lead, antimony, and barium in the function of time, it was established that the chemical composition of particles did not reveal significant dependence on time of collecting samples after shooting. However, in samples of particles collected in longer intervals after shooting a relatively greater contribution of particles of the diameters, more than 1 micrometer occurred in the whole population and their shape significantly differed from the spherical one ().

From the performed examinations one can conclude that the metallic particles reveal much greater half-life time for specimens collected from the face and hair as well as from the clothing of the shooter than from the person's hands. Thus, it is appropriate to formulate a recommendation that, in addition to samples from hands of the suspects, samples collected from their face and hair as well as clothing should be included into the evidential material, in particular, when more than 4 hours passed between the incident and the collection of the evidence.

3.5. The Assessment of the Risk of Misidentification of Gunshot Residue

Results of the research on the kinetics of the loss of GSR particles from the shooting person convince one that the particles are related to the place and time of using a firearm. However, relating an individual with the fact of using a firearm demands not only providing the number, chemical contents, and morphology of the particles detected in the evidence material collected from the person, but also assessing their evidential value. A robust assessment of the evidential value of GSR demands the evaluation of the risk of random contamination with these particles of the selected professional environments due to their primary and secondary transfer. A lack of sufficient information related to prevalence of GSR particles in Poland inspired the screening research performed by the author [ 18, 19].

In specimens taken from hands of 100 people declaring no contact with firearms, only one spherical particle containing lead, antimony, and barium was found. Numbers of particles found in specimens collected from hands of 50 shooters varied from zero to numbers greater than 100 and were strongly correlated with the time interval between last shooting and collecting specimens. With the application of the criterion of low risk of contamination of hands with GSR, that is, 5 hours after last shooting or handling a gun, very low numbers of GSR particles were encountered among the firearm users. Sixteen out of 17 specimens taken from hands of police officers (94%) and 10 out of 14 of hunters (71%) were free from spherical Pb-Sb-Ba particles. Moreover, the potential secondary transfer was traced on the example of families of 5 hunters as well as chosen activities, such as examinations of short-range gunshot damages in clothing, reloading a gun, or collection of specimens from shooters. All these have shown that the level of secondary transfer might be significant and depends mainly on the recent taking part in shooting activity and its frequency. The obtained results remain in agreement with some mocked situations of the secondary transfer studied by French at al. [ 20].

Results of the study allowed formulating a recommendation that crime scene officer, who is to collect evidence microtraces from suspects, should not be a user of firearms, or should collect a control sample from his/her hands prior to the evidence collection-a procedure for prevention from contamination of the evidence material at its collection.

Also a potential risk of contamination with the characteristic GSR particles of the laboratory housing the SEM-EDX analytical system serving to the GSR examinations for forensic expertise was evaluated. Analysing 55 specimens of microtraces collected in various time intervals, no particles of the chemical contents and morphology of gunshot residue were revealed. That confirmed the procedures of secure handling of the evidence material for GSR search to be appropriate and preventing from the potential contamination [ 18, 19].

From the performed research one can conclude that the greater the number of revealed particles the greater their evidential value in the aspect of the relation of an individual with a shooting incident. The recommendation on the securing clothing of the suspects due to a rapid loss of the GSR particles from people's hands appears to be right also for increasing the possibility of detection of a greater number of particles, when examining more evidence items. The value of analytical findings as a group of particles revealing defined chemical and morphological characteristics rather than solely their number was also demonstrated by Gauriot et al. [ 21].

Evaluation of shooting incidents with the use of modern less toxic ammunition types that produce less characteristic primer residue may demand an application of techniques complementary to SEM-EDX, such as integrated ion beam analysis (IBA) for examinations of inorganic component [ 22, 23], or variety of spectrometric and chromatographic methods for analysis of organic gunshot residues [ 24- 27].

4. Summary

This paper presents a review of chosen aspects of examinations of inorganic gunshot particles by means of SEM-EDX technique. In the first stage, original research methodology of gunshot particles was worked out, which embraced not only a precise and repeatable procedure of detection and identification of particles in the automatic manner, but also a representation of the obtained analytical data in the form of the frequencies of occurrence of particles of certain chemical class (or a class of certain range of the effective diameters) within the whole population of particles revealed in a specimen.

On the basis of this methodology, some relationships were established between the chemical and morphological properties of populations of particles and factors, such as the type of ammunition, the distance from the gun muzzle to the target, the type of a substrate on which the particle sediments, and the time between shooting and collecting the specimens.

Significant differences in the chemical composition of GSR originating from various types of ammunition, depending mainly on the composition of the primer mixture, were established. This gave rise to working out the method of group identification of ammunition used in a shooting incident, when the cartridge case is not available for examinations.

Chemical and morphological examinations of particles collected from the shooter's hands from the interior of, physically, the same cartridge revealed either similarities or discrepancies depending on the chemical composition not only of the primer, but also other parts of the cartridge. This ought to be taken into account in the expert's report for not falsely excluding the possibility of a suspect to be a partaker in a shooting incident.

It has been established that the distribution of particles in the surroundings of the shooting gun is not uniform. The numbers of particles, their chemical composition, and their morphological features depend on the distance from the muzzle of the shooting gun and the type of the substrate the particles sediment on. Results of this study gave rise to working out the method of shooting distance estimation from the physical and chemical examinations of GSR pattern around the gunshot wounds and damages-extending the possibilities of shooting distance estimation with range of about 50-100 cm, in addition to the three categories commonly used until now: (i) contact or a nearest vicinity shot (about 0-1 cm), (ii) close distance shot (about 1-50 cm), and (iii) distant shot.

A consistency of the elemental composition of the residue remaining inside the cartridge case with that of the primer was observed, whereas the elemental contents of the airborne particles (e.g., collected from the shooter's hands) differed. That was most probably resulting from the interactions of the products of the reaction of the primer and the propellant with other parts of the ammunition (i.e., materials of cartridge case, the projectile core, and jacket) as well as the interior surfaces of the gun barrel. Thus, it was established that GSR occurs in the subsequent stages of the explosives reaction of the primer and the propellant propagate inside the cartridge case and the gun barrel only in one direction-towards the muzzle, and so they do not return or mix with each other.

The fact of variability of the chemical composition of particles in the dependence on the distance from the shooting gun, both in the direction of shooting and in the opposite one, could be utilised for establishing the positions of the partakers in the shooting incident in relation to the firearm and so to the direction of shooting.

The kinetics of the loss of GSR particles simultaneously from the shooter's (i) hands, (ii) face and hair as well as (iii) garments was established in the form of the half-life times. It was also found that the chemical composition and sizes of particles reveal practically no influence on the loss of particles, whereas irregularly shaped particles turned out to be more persistent than the regularly spherical ones.

The fundamental information necessary for the assessment of the risk of contamination with GSR particles of selected populations in Poland was obtained and utilised for working out the rules of its elimination or diminishing, while handling the evidence in shooting cases.

Each of the worked out aspects of chemical analysis of metallic particles may significantly contribute to reconstruction of the course of a shooting incident. In spite of the fact that usually the physical and chemical examinations lead to a group identification and are complementary to other types of information included in the cases files, in specific cases they may be decisive in establishing the circumstances of the incident.

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Scanning Electron Microscopy and X-Ray Microanalysis for Chemical and Morphological Characterisation of the Inorganic Component of Gunshot Residue: Selected Problems

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Inorganic components of gunshot residue (GSR), in particular, metallic particles originating from the ammunition primer, reveal characteristic properties and so provide themselves a high value evidence of using a firearm. Only few particles, of total mass no greater than 100 picograms, can be accepted as the evidence relating an individual with a shooting incident.

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Ohio Attorney General Mike DeWine - Bureau of Criminal Investigation

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Ohio Attorney General Mike DeWine - Bureau of Criminal Investigation

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Blood Types & Groups Chart | A, B, AB & O | Red Cross Blood Services

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Blood Types & Groups Chart | A, B, AB & O | Red Cross Blood Services

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Not all blood is alike. Learn about blood typing and the rarest and most common types of blood and how they can impact your blood donation.

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What Is Firearm and Tool Mark Identification?

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What Is Firearm and Tool Mark Identification?

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What Is Firearm and Tool Mark Identification?

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Toolmark Identification is a discipline of forensic science which has as its primary concern to determine if a toolmark was produced by a particular tool. Firearm Identification is a sub-category of toolmark identification; which has as its primary concern to determine if a bullet, cartridge case, or other ammunition component was fired by a particular firearm.

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American Academy of Forensic Sciences – A professional society dedicated to the application of science to the law

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American Academy of Forensic Sciences – A professional society dedicated to the application of science to the law

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The American Academy of Forensic Sciences is a multidisciplinary professional organization that provides leadership to advance science and its application to the legal system. The objectives of the Academy are to promote professionalism, integrity, competency, education, foster research, improve practice, and encourage collaboration in the forensic sciences.

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The American Academy of Forensic Sciences is a multidisciplinary professional organization that provides leadership to advance science and its application to the legal system. The objectives of the Academy are to promote professionalism, integrity, competency, education, foster research, improve practice, and encourage collaboration in the forensic sciences.

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The following problems require an understanding of the principles of mass spectrometry. Most of the questions concern the identification of unknown compounds from their mass spectra.

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The following problems require an understanding of the principles of mass spectrometry. Most of the questions concern the identification of unknown compounds from their mass spectra.

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Loading a Gel for Electrophoresis | Carolina.com

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Loading a Gel for Electrophoresis | Carolina.com

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How to Use a Micropipette | Carolina.com

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How to Use a Micropipette | Carolina.com

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The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high-quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment.

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Anna Ayala, the woman who found a finger in a bowl of Wendy's chili last month, was arrested on Thursday and charged with grand larceny and attempted grand larceny. Police have not been able to determine the origin of the finger, even after searching for matches in " the F.B.I.'s database of about 50 million prints." Who's in the FBI database?

Criminals, suspected criminals, government employees, military personnel, and a few others. The repository has three components: A criminal file, a civil file, and a military file. The criminal file is the biggest and comprises the 50 or so million entries that get searched when police are trying to identify a print left at a crime scene. The civil file, not surprisingly, includes government employees, and the military file covers the armed forces.

Local and federal law enforcement officers typically submit fingerprints to the FBI's criminal file for every person they arrest on a serious charge, whether or not there is an eventual conviction. (The print from the chili finger is not in the database; as a result of her arrest on Thursday, Ayala's own fingerprints are.) The fingerprints of all FBI employees and some other sensitive government employees are also kept in the criminal file-the government wants to know ASAP if these people commit crimes-as are the prints of missing persons, amnesiacs who don't remember their names, and unidentified dead bodies. The FBI says it adds seven or eight thousand entries to the criminal file every day.

If a suspected criminal is found to be not guilty, his or her prints are supposed to be removed from the system, but that doesn't always happen. You can also petition to have your prints removed if you received an official pardon for your crime or if the laws governing the severity of your crime have changed since your arrest.

Dead people are removed from the database when their data is submitted to the FBI by a coroner's office. It used to be that anyone over the age of 65 who hadn't been arrested or imprisoned in 10 years was assumed to be dead or not an active criminal and removed from the file. In more recent years the age limit has been increased.

Law enforcement officials use the criminal file for the identification of crime-scene prints, as well as for criminal background checks. But there are also a number of federal and state laws that permit civilians to consult the database with the help of a state agency in special circumstances. The National Child Protection Act, for example, allows anyone who works with children to be fingerprinted and checked against the criminal file. Licensed stock brokers, bankers, and gambling-casino employees can all be checked by their employers as well. In recent years, the number of these background checks has increased dramatically; today civil searches account for almost half of all submissions to the bureau.

How do you know if you're in the FBI database? According to Department of Justice rules, you have the right to submit your own fingerprints for a background check on yourself. (This allows you to contest anything that might be on your rap sheet.) Just write out a formal request and send it to the FBI, along with a full set of fingerprints and a money order for $18.

Explainer thanks Ken Moses of Forensic Identification Services and Peter Higgins of the Higgins-Hermansen Group.

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Anna Ayala, the woman who found a finger in a bowl of Wendy's chili last month, was arrested on Thursday and charged with grand larceny and attempted grand larceny. Police have not been able to determine the origin of the finger, even after searching for matches in " the F.B.I.'s database of about 50 million prints."

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Let’s Talk About FINGERPRINTS | Wrongful Convictions Blog

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Let’s Talk About FINGERPRINTS | Wrongful Convictions Blog

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Fingerprints, more technically known as "friction ridge analysis", have been around for well over 100 years; at least since Francis Galton published his seminal work simply titled "Finger Prints" in London in 1892. In fact, fingerprints are still analyzed according to their "Galton characteristics", shown below.

In today's fingerprint jargon, these are called "minutiae", but they are still the same features that were cataloged by Galton in 1892. These "minutiae" are meaningful only in relation to their relative position within the swirls and whorls of the overall friction ridges comprising the fingerprint. Fingerprints that are forensically obtained from crime scene objects and weapon surfaces are called "latent prints". There is a level of fingerprint detail even finer than "minutiae" which consists of very small irregularities in common features, but it is my belief that these are rarely seen in latent prints.

Now .... did you know that it has never been statistically validated that fingerprints are unique? And what's more, I don't believe it ever will be. The experimental population required to statistically certify uniqueness renders the "experiment" totally impractical. Given sufficient data, it might (I repeat - might) be possible to develop statistics for "probability of occurrence", but no such data exists. [This is where DNA sets itself apart from all other forensic disciplines - it yields a hard statistic for probability of a match or non-match.]

However, over 100 years of anecdotal data, empirical observations, and folklore have bestowed upon "fingerprints" the mantle of infallibility within the justice system. Fingerprints have been responsible for more criminal identifications, by far, than any other forensic discipline. But are they infallible? Not so. Read on.

About AFIS. In 1999, the FBI (US Federal Bureau of Investigation) launched the computer-based AFIS (Automated Fingerprint Identification System), which has since been superceded by IAFIS (Integrated Automatic Fingerprint Identification System). The FBI is now also working on NGI (Next Generation Identification) which will include palm prints, iris, and facial identification data. IAFIS currently has over 120 million peoples' prints on file, and it processed 61 million 10-print inquiries in 2010. This has been a boon to law enforcement, because it would clearly be impossible for human examiners to conduct 61 million fingerprint comparisons in a year. However, this efficiency comes with a price. Automated fingerprint matches are much more prone to error than those done by humans, and automated matches need to be confirmed by competent human examiners. But even the combination of automated match with human verification can produce errors. Just ask Brandon Mayfield. Brandon Mayfield is a Seattle, WA attorney whose prints were matched by AFIS to a partial print from the Madrid train bombing, and this was confirmed by human FBI experts. The FBI called it a "slam dunk", "bingo" match, and Mr. Mayfield was taken into custody. But guess what - it turned out that the print was actually from a man named Ouhnane Daoud, an Algerian. And by the way, Mr. Mayfield was awarded a $2 million settlement.

Fingerprint identification is plagued by the problem of "partials". A partial print is an area of friction ridge pattern that is smaller than the "whole" print. When people are "fingerprinted", a record is made of the entire friction ridge surfaces of the fingers. It is not common for a forensic latent print to be anything more than a partial, and this creates a problem with "matching accuracy", because the examiner has to try to match a small piece of a print to the whole-print exemplar. And the more "partial" the latent print is, the higher the error rate climbs. In addition, latent prints are frequently "smudged", and because skin is elastic it can expand and compress and twist, distorting the latent print. The number of matching minutiae that is generally accepted for declaring a "match" hovers around 14, but matches on partials have been declared with as low as 8. The only figure I've seen published for "false positives" from partials is 1%-4% (I don't have attribution for this). False positives from partials gets worse for automated matches.

Still another issue is that fingerprint matching accuracy is dependent upon the competence of individual examiners. In 1995, the Collaborative Testing Service administered an examiners' proficiency test that was pre-approved by the International Association for Identification (IAI). The results were less than good. Four suspect exemplar cards with prints of all ten fingers were provided to test takers along with seven latents. Of 156 examiners taking the test, only 68 (44%) correctly classified all seven latents. In total, the test results contained 48 incorrect identifications.

In 2007, a Baltimore County (MD) judge ruled that fingerprints were not reliable enough to be used as evidence against a defendant facing a possible death sentence.

Now, even having said all this, the bottom line is - finger prints are "pretty good" (even though there is NO data from which to compute a probability of occurrence). But are they infallible? No.

I also strongly encourage you to read the companion post by Martin Yant titled: "How to reduce fingerprint errors."

It's difficult to do this topic justice in a blog post, so here is some reference material for you:

1) SWIRLS AND WHORLS: LITIGATING POST-CONVICTION CLAIMS OF FINGERPRINT MISIDENTIFICATION AFTER THE NAS REPORT,Prof. Jackie McMurtrie, University of Washington School of Law.
Swirls & Whorls
2) MORE THAN ZERO: ACCOUNTING FOR ERROR IN LATENT FINGERPRINT IDENTIFICATION, Prof. Simon Cole, University of California at Irvine.
More Than Zero
3) THE ACHILLES' HEEL OF FINGERPRINTS, Jennifer Mnookin, The Washington Post.
The Achilles Heel of Fingerprints
4) MOTION TO EXCLUDE EXPERT TESTIMONY ON FRICTION RIDGE ANALYSIS, OR, IN THE ALTERNATIVE, TO CURTAIL SUCH TESTIMONY UNDER DAUBERT V. MERRELL DOW PHARMACEUTICALS, The Innocence Project of New Orleans. [Editor's Note: If interested, the IPNO also has Daubert motion templates for "firearms identification" and "microscopic hair comparison".] This is very well done, but we'll have to see how it does in court.
IPNO - Motion to exclude friction ridge analysis
5) And if you're really, really into this, here's the FBI Guide on fingerprint processing.
FBI Fingerprint Processing Guide
Phil Locke

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Fingerprints, more technically known as "friction ridge analysis", have been around for well over 100 years; at least since Francis Galton published his seminal work simply titled "Finger Prints" in London in 1892. In fact, fingerprints are still analyzed according to their "Galton characteristics", shown below.

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Crime scene investigation and forensic science information. Documenting crime scenes, collection and preservation of evidence, articles, forum, videos, resources.

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Test your smarts on forensics in this special topics quiz! | Science | AAAS

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Test your smarts on forensics in this special topics quiz! | Science | AAAS

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Test your smarts on forensics in this special topics quiz!

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Test your knowledge of the week's hottest forensics stories!