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"Mass shooters over 60 also tend to have prior criminal records"

"From 1980 to 1989, the median age of mass shooters was 39. Over the next two decades, it was 33. And from 2010 to 2019, it was 29. Since 2020, the median age of mass shooters has come down to just 22 years old"

"though mass shooters at offices, warehouses and houses of worship skew older, shooters at K-12 schools, colleges and universities tend to be younger — in large part because many school shooters tend to be current or former students."

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Op-Ed: Older mass shooters are rare. Here’s how they differ from young assailants

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Before the attacks in Monterey Park and Half Moon Bay, mass shooters were getting younger and only six in a database going back to 1966 were over 60.

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"academic studies have found that about a quarter of shooters were younger than 25."

"When the Post analyzed these shootings, it found that more than two-thirds were committed by shooters younger than 18. The analysis found that the median age for school shooters was 16."

"A large-scale RAND study found that 26% of mass public shooters between 1976 and 2018 were younger than 25. Another study from the University of Alabama found that 27.2% were younger than 25, and that 6.8% were younger than 18."

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Sen. Chris Murphy, D-Conn., has worked to enact restrictions on guns ever since the Sandy Hook school shooting in Newtown, Connecticut, an area he then-represented in the U.S. House of Representatives.

After another elementary school shooting - this one in Uvalde, Texas, on May 24, 2022 - Murphy gave an impassioned speech on the U.S. Senate floor to urge redoubled efforts to curb gun violence. The speech made the rounds of news shows and was widely shared on social media.

In an interview with CNN the day of the shooting, Murphy focused on the young age of the shooters in Uvalde and a May 14 mass shooting in Buffalo.

"I want to get rid of these assault weapons," Murphy said. "But maybe we can find common ground on just limiting who can get access to them, maybe say you have to be 21 instead of 18, seeing that most of these killers tend to be 18, 19 years old."

This fact-check will focus on whether "most of these killers tend to be 18, 19 years old."

When we checked with Murphy's office, they pointed to a database project undertaken by The Washington Post that tracks every act of gunfire at a primary or secondary school during school hours since the Columbine High School massacre April 20, 1999. The Post found more than 200 incidents that met the project's criteria.

When the Post analyzed these shootings, it found that more than two-thirds were committed by shooters younger than 18. The analysis found that the median age for school shooters was 16.

So, using this criteria, Murphy is correct, even slightly understating the case.

For overall mass shootings - not just school shootings - academic studies have found that about a quarter of shooters were younger than 25.

A large-scale RAND study found that 26% of mass public shooters between 1976 and 2018 were younger than 25. Another study from the University of Alabama found that 27.2% were younger than 25, and that 6.8% were younger than 18.

A final point: Murphy referred to "killers," but the Post analysis he relied on included both incidents that resulted in deaths and those that did not.

Murphy said after the shooting in Uvalde that "most of these killers tend to be 18, 19 years old."

That's largely accurate when looking at school shootings alone, according to a Washington Post database of school shootings since 1999. The database did include shootings that did not result in a death, and the share of teenagers committing mass shootings overall is smaller.

We rate the statement Mostly True.
RELATED: All of our fact-checks about guns
Chris Murphy, interview with CNN, May 24, 2022

Washington Post, " More than 311,000 students have experienced gun violence at school since Columbine," May 25, 2022

RAND, " Mass Shootings in the United States," updated April 15, 2021

Adam Lankford and Kaitlyn B. Hoover, " Do the Ages of Mass Shooters Matter? Analyzing the Differences Between Young and Older Offenders," March 11, 2019

Email interview with Andrew Morral, senior behavioral scientist at the RAND Corp., May 25, 2022

Email interview with Rebecca Drago, spokesperson for Chris Murphy, May 25, 2022

In a world of wild talk and fake news, help us stand up for the facts.

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PolitiFact - Fact-checking Sen. Chris Murphy on the ages of mass shooters

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Sen. Chris Murphy, D-Conn., has worked to enact restrictions on guns ever since the Sandy Hook school shooting in Newtown, Connecticut, an area he then-represented in the U.S. House of Representatives. After another elementary school shooting - this one in Uvalde, Texas, on May 24, 2022 - Murphy gave an impassioned speech on the U.S.

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"Some of the same lawmakers stood by Lee’s side three years ago, when he announced his support for eliminating a requirement for people 21 and older to get a permit to carry handguns publicly in Tennessee.The change became law in 2021. In a recent court settlement, the state agreed to drop the minimum age to 18."

"Kentucky passed a measure earlier this year declaring the state a “Second Amendment Sanctuary,” prohibiting local and state police from enforcing any federal firearm regulation banning guns, ammunition, or firearm accessories that took effect after Jan. 21, 2021."

"Neither state has adopted such a law, commonly known as so-called “red flag” laws.To date, 19 states have red flag laws on the books — with many lawmakers enacting them after tragedies. Notably, Florida did so after the 2018 mass shooting at Marjory Stoneman Douglas High School in Parkland"

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The Associated Press

Two weeks after one of his wife's closest friends was killed in a Nashville school shooting, Tennessee Gov. Bill Lee on Tuesday called for legislation that would keep firearms away from people who could harm themselves or others

As shootings hit close to home, govs wrestle with next stepsBy KIMBERLEE KRUESI and BRUCE SCHREINERAssociated PressThe Associated PressNASHVILLE, Tenn.

NASHVILLE, Tenn. (AP) - Two weeks after one of his wife's closest friends was killed in a Nashville school shooting, Gov. Bill Lee on Tuesday called on Tennessee's GOP-dominant General Assembly to pass legislation that would keep firearms away from people who could harm themselves or others.

Lee, a Republican, is the latest prominent public official to experience personal loss in a mass shooting while having to delicately balance how to use his authority to help prevent future tragedies through policy.

Kentucky Gov. Andy Beshear confirmed that he, too, had lost one of his best friends when a gunman killed five people at a bank in downtown Louisville and injured eight others on Monday.

Lee told reporters Tuesday that he talked with Beshear, a Democrat, after Monday's shooting, which claimed the life of Tommy Elliott, a lifelong friend of Beshear's. Four other people also were killed.

On March 27, Cynthia Peak, 61, a substitute teacher and friend of Lee's wife, Maria, was slain along with two other adults and three children at a Christian Elementary School in Nashville.

Lee's call for a law designed to prevent people who may hurt themselves or others from acquiring firearms comes as Republicans maintain supermajority control in both the Kentucky and Tennessee statehouses, where GOP lawmakers have long resisted limiting gun access.

Neither state has adopted such a law, commonly known as so-called "red flag" laws.

To date, 19 states have red flag laws on the books - with many lawmakers enacting them after tragedies. Notably, Florida did so after the 2018 mass shooting at Marjory Stoneman Douglas High School in Parkland that killed 17 students. Law enforcement officials had received numerous complaints about the 19-year-old gunman's threatening statements.

In allowing courts to issue what are known as extreme risk protection orders, the laws are intended to temporarily remove guns - usually for up to a year - from people showing signs of potentially violent behavior. In many cases, family members or law enforcement must petition a court for an order.

Experts in red-flag laws contend that the laws have undoubtedly saved lives, be it in cases involving planned mass shootings, suicides or potentially deadly domestic violence cases. Yet an Associated Press investigation last year found that most U.S. states barely use red flag laws. It's a trend blamed on a lack of awareness of the laws and resistance by some authorities to enforce them even as shootings and gun deaths soar.

But as mass shootings continue across the U.S., resistance to make significant changes to gun restrictions remains high.

In Tennessee, lawmakers have been more welcoming to strengthening school safety than addressing gun access as they prepare to finish their work in the coming weeks.

A week ago, Lee was flanked by Republican lawmakers as he called on the General Assembly to pass legislation that would better protect students attending public and private schools. Some of the same lawmakers stood by Lee's side three years ago, when he announced his support for eliminating a requirement for people 21 and older to get a permit to carry handguns publicly in Tennessee.

The change became law in 2021. In a recent court settlement, the state agreed to drop the minimum age to 18.

On Tuesday, Lee stood alone, and he acknowledged that no lawmaker had yet agreed to sponsor the latest legislation he was proposing. Lee also did not disclose many details on his plans or what the proposed bill would look like. Instead, he said that he wanted lawmakers to come up with a solution.

"We will have to work together in order to get this done, but I believe we can. I believe we will," Lee said.

Kentucky passed a measure earlier this year declaring the state a "Second Amendment Sanctuary," prohibiting local and state police from enforcing any federal firearm regulation banning guns, ammunition, or firearm accessories that took effect after Jan. 21, 2021.

As he seeks reelection, Beshear allowed the bill to become law without his signature.

Previous efforts to pass a red-flag law in Kentucky have made no headway in the Legislature. Lawmakers have adjourned for the year, and currently aren't scheduled to meet until January. But after the school shooting, local leaders urged lawmakers to take meaningful action as they warned that anyone may be impacted by gun violence.

One of them is Louisville Mayor Craig Greenberg, who also counted Tommy Elliott as a friend.

"This isn't about partisan politics. This is about life and death. This is about preventing tragedies. You may think this will never happen to you. Never happen to any of your friends or loved ones. I used to think that," said Louisville Mayor Craig Greenberg, who had a man storm his campaign headquarters last year and fire a weapon point-blank at him. "The sad truth is that now, no one in our city, no one in our state, no one in our country has that luxury anymore."

___

Schreiner reported from Frankfort, Kentucky.

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As shootings hit close to home, govs wrestle with next steps - Breitbart

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Two weeks after one of his wife's closest friends was killed in a Nashville school shooting, Tennessee Gov. Bill Lee on Tuesday called for legislation that would keep firearms away from people who could harm themselves or others As shootings hit close to home, govs wrestle with next stepsBy KIMBERLEE KRUESI and BRUCE SCHREINERAssociated PressThe Associated PressNASHVILLE, Tenn.

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"Guns surpassed car accidents as the leading cause of death for children and teenagers in 2020"

"2,834 victims have lost their lives in 544 mass killings since 2006"

"2022 saw the second most mass killings in a single year since tracking began."

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The horror and tragedy of mass shootings in American schools, churches and other public places capture the nation's attention. But these are only part of the larger violence of mass killings - deaths by guns, knives, fires, vehicles and other weapons in public and in private - that plague the U.S., research shows.

Over the past decade, USA TODAY, along with Northeastern University and The Associated Press, has been tracking all mass killings in the United States. When it comes to gun violence, our database is narrower than other tracking sites, such as the Gun Violence Archive, that include shootings that injure large numbers of people but kill no one. However, our data is broader in other ways. It includes every mass killing since 2006 from all weapons in which four or more people, excluding the offender, were killed within a 24-hour time frame.

The number of mass killings in 2022 is about average compared with previous years despite recent shootings that captured public attention. The number of victims is somewhat higher than average but still below previous highs.

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James Alan Fox, a professor of criminology, law and public policy at Northeastern University in Boston, oversees the database and continues to add information drawn from media reports, FBI data, arrest records, medical examiners' reports, prison records and other court documents.

This is what we have learned:

Cases in which someone shoots strangers in a public place usually get the most attention. But fatal public shootings are a small fraction of all mass killings. There has been a spike in these types of killings over the past few years, but the rate of occurrence has remained relatively flat since the mid-2000s.

"A guy who kills his wife and children and sometimes kills himself is the most common type of mass killing," Fox said. Mass killings take place far more often in private homes than in schools, markets or churches.

Mass shootings in which family members are targeted are twice as common as fatal public mass shootings in which strangers are killed. In our database, the public category excludes killings related to drug deals, gang disputes, robberies and other criminal activity.

On average, our data shows that five people die in a mass killing of any kind, compared with seven in a fatal public mass shooting. Though these public killings result in more per-incident deaths, other types of mass killings happen more frequently and result in more victims overall.

Other data sources corroborate the outsize role of family mass killings. According to a study by the gun control group Everytown for Gun Safety, nearly 3 in 4 children and teens killed in mass shootings over the past decade died in an incident connected to domestic violence.

Guns surpassed car accidents as the leading cause of death for children and teenagers in 2020. The school security industry has grown into a $3.1-billion-a-year market, but our database shows that when it comes to mass killings, most children die at home.

The majority of mass killings are fatal mass shootings. These events usually happen about two dozen times a year. Analysis shows non-gun-related deaths make up just under 20% of mass killings.

Semiautomatic handguns are far more common in mass killings than guns that are typically classified as assault weapons. According to Fox, handguns are easily concealable and some can be equipped with large-capacity magazines. In this database, the long guns category includes any gun larger than a handgun, including rifles and shotguns.

Far more people kill themselves with a firearm each year than are killed with one, according to statistics from the Centers for Disease Control and Prevention analyzed by Everytown for Gun Safety. Nearly two-thirds of all gun deaths in the U.S. are suicides. More than half of suicides involve guns. Since 2006, firearm suicide rates have been steadily increasing.

Men who own handguns are almost eight times more likely to die of gun suicides than men who don't, according to a California study published in 2021 by the New England Journal of Medicine that examined more than 25 million gun owners. Women were 35 times more likely to commit suicide if they own a handgun.

According to one study by James Knoll and Ronald Pies in the medical trade publication Psychiatric Times, mass killers are typically angry, aggrieved, emotionally unstable people who seek retribution or revenge for perceived mistreatment, rejection or humiliation. Offenders are often socially isolated and have limited social support.

"The ones who are more apt to commit mass murder are the ones who are paranoid, and who are suspicious and mistrusting and think that everyone is against them," said Michael Stone, a forensic psychiatrist at Columbia University who maintains a database of 350 mass killers going back more than a century. "It's somebody who has fewer capacities at his disposal for adjusting to the crisis of losing the job or the girlfriend and will feel that life is over."

Four in 10 men report that they own a gun. Gun owners are also predominantly white. According to Stone, men tend to be more aggressive and are more prone to violence. Offenders who commit public mass killings tend to be younger. At the same time, most family homicides involve middle-aged men.

"As far as the offender age goes, for the family killings, you don't have 21-year-olds who have a wife and three kids," Fox said.

With a few exceptions, victims and offenders in mass killings tend to reflect the population. White Americans make up the largest overall percentage, 46%, of mass killing victims and 36% of offenders. White perpetrators commit more than half, 52.3%, of family mass killings and 54.4% of public mass killings.

In felony mass killings - we define these as being associated with criminal activity such as robbery, illicit drug trade or gang conflict - Black perpetrators commit 57.1% while Hispanic offenders commit 17.7% of them, both more than their population shares, Fox says.

They take place across the country in towns of all sizes. Homicides with fewer than four victims are more common in larger cities, but mass killings with higher death tolls often take place in smaller towns or rural settings.

Mass killers typically target certain people for a number of specific reasons, including a specific event like the end of relationship or loss of a job. Mass killings are rarely indiscriminate. Perpetrators usually plan their assaults for days, weeks or months.

According to a study by Melanie Taylor in the International Journal of Offender Therapy and Comparative Criminology, a failed or estrangedrelationship is the most common reasons for committing a mass killing. Perpetrators are often dealing with relationship and financial struggles for an extended time, and a particularly traumatic event can push them to kill.

The motive for a mass killing is often revenge. Most commonly, the killer seeks to get even with people they know for real or perceived slights. "Sometimes it's marital discord where a man kills the wife out of anger, and the children as well by seeing them as being associated with the wife," Fox said.

There are also mass killings in which disgruntled employees kill their managers and other co-workers. But these attacks happen rarely - one or two a year, according to Fox. In the case of losing a job, a mass killing usually results in the slaying of family members.

Other common motivations include gaining control, carrying out a robbery or sending a message by committing a killing, according to Fox. Perpetrators sometimes target a certain group of people, such as immigrants or people of a single race, but choose individuals at random. Some mass killings happen for reasons that cannot be immediately identified.

"In the aftermath of a mass killing, all those missed warning signs become crystal-clear when hindsight is 20/20," Fox said. "It is really not possible to predict in a reliable way those who will commit a mass killing."

Profiles of mass killers reveal common elements shared by many people in the general population. Countless Americans may be angry, frustrated, reclusive, quick to blame others for their shortcomings, willing to post hateful messages on social media sites, or make threats - but relatively few will kill, much less commit mass killings.

"One misconception is that they are easy to spot, that a mass killer looks like mass killers are supposed to look," Fox said. "But that's not the case. They oftentimes are extraordinarily ordinary, you wouldn't suspect."

Mass killers usually don't have criminal records. Researchers at Columbia University analyzed 1,315 mass murders of all types worldwide between 1900 and 2019 and found that 20% of mass killers had histories of being subject to a restraining order, arrest or incarceration.

A study by Emma E. Fridel in the Journal of Interpersonal Violence that looked at all mass murders between 2006 and 2016 found that 17% of offenders had a history of domestic violence. For killings in public places, the number was 7%. It is quite rare for a heated dispute to escalate into a mass killing.

Several studies confirm that most shooters who kill four or more victims are not psychotic or hallucinatory and haven't been treated for mental health problems. An analysis of Columbia University's mass murder database shows that 11% of all mass murderers had serious mental illness.

"There's no mental illness whose symptom is hurting someone else, let alone shooting somebody else," said Jonathan Metzl, a professor of psychiatry at Vanderbilt University.

"Those illnesses are marked by low energy and low mood and poor cognitive planning sometimes, because they interfere with the way you think," Metzl said. "So planning something as complicated as a mass shooting is not going to be the easiest thing."

The USA TODAY/AP/Northeastern University mass killing database contains information on incidents, offenders, victims and weapons for all multiple homicides with four or more victims killed in the United States from 2006 to the present.
Definitions
A mass killing is defined as the intentional killing of four or more victims - excluding the deaths of unborn children and the offender(s) - by any means within a 24-hour period.

This definition includes cases involving all weapons (shooting, blunt force, stabbing, explosives), types (public, felony-related, and familicides), motivations (domestic dispute, profit, revenge, terrorism, hate), victim-offender relationships (stranger, family, acquaintance, co-worker), and number of locations. The time frame of 24 hours was chosen to eliminate conflation with spree killers who kill multiple victims over several days in different locations and to satisfy the traditional requirement of occurring in a "single incident," even if that incident involves an offender targeting multiple locations in an extended assault but within a relatively short time span. However, offenders who kill four or more victims during any 24-hour period of time as part of a multi-day spree are included, as are all their victims within seven days of the mass killing. Negligent homicides related to driving under the influence or accidental fires are excluded because of the lack of intent. Finally, only incidents occurring within the 50 U.S. states and the District of Columbia are included in the database.

Consistent with the traditional definition, fatal mass shootings are mass killings (four or more victim fatalities) in which most or all the victims are killed by gunfire. This differs from an alternative definition used by the Gun Violence Archive that includes incidents in which at least four victims are shot regardless of whether the injury is fatal. Less than 5% of the mass shootings listed in the Gun Violence Archive are defined as mass killings in our database. Our definition of a fatal mass shooting also differs from an active shooter event which, as characterized by the FBI, involves an individual actively engaged in killing or attempting to kill people in a populated area. Less than 25% of active shooter events result in four or more victim fatalities, constituting a mass killing.
Methods
Researchers at USA TODAY first identified potential incidents using the FBI's Supplementary Homicide Reports (SHR). Homicide incidents in the SHR were flagged as potential mass killing cases if four or more victims were reported on the same record, and the type of homicide was coded as "murder or non-negligent manslaughter." Cases were subsequently verified utilizing media accounts, court documents, academic journal articles, books and local law enforcement records obtained through Freedom of Information Act (FOIA) requests. Each data point was corroborated by multiple sources, which were compiled into a single document to assess the quality of information. When sources were contradictory, official law enforcement or court records were used, when available, followed by the most recent media or academic source. Case information was subsequently compared with other available mass killing or mass shooting databases to ensure validity. Incidents listed in the SHR that could not be independently verified were excluded from the database.

In 2016, primary data collection and verification efforts shifted from USA TODAY to Northeastern University. Northeastern researchers conducted extensive searches for incidents not reported in the SHR during the time period, utilizing internet search engines including Lexis-Nexis, Google News, and Newspapers.com. Search terms included: [number] dead, [number] killed, [number] slain, [number] murdered, [number] homicide, mass murder, mass shooting, massacre, rampage, family killing, familicide and arson murder. Offender, victim and location names were also directly searched when available. Northeastern University researchers also independently verified data collected by USA TODAY staff and filled in missing information, sometimes involving updated reports on older cases.

In December 2018, a Memo of Understanding (MOU) was signed by The Associated Press, USA TODAY and Northeastern University to formalize a joint initiative to maintain and expand the mass killing database previously housed at USA TODAY. The Associated Press hosts the database and maintains the data entry tool, USA TODAY has developed and maintains the public website for and visualizations of the database, and Northeastern University manages data collection and updates.

The full database currently consists of four linked data tables with a total of 59 data fields (not counting indicators for the availability of offender/victim identity) -18 fields for each incident, 20 fields for each offender, 13 fields for each victim killed and eight fields for each weapon used. Most variables, with the notable exception of victim names, are available for public download. The remaining data is reserved for individuals affiliated with The Associated Press, USA TODAY/Gannett, and Northeastern University's School of Criminology and Criminal Justice, and others by permission of all three organizations. Moving forward, additional variables may be added to the full database as well as the public subset. While USA TODAY respects diversity of gender, this database instead uses sex as a datapoint as is common in crime statistics.
Read more about the data. Download the data.
Any questions or corrections concerning the data should be directed to James Alan Fox at j.fox@northeastern.edu.
Credits
Research and reporting: Karina Zaiets and George Petras

Design and development: Veronica Bravo and Mitchell Thorson

Editing: Shawn J. Sullivan
Paul Overberg, Meghan Hoyer, Mark Hannan, Jodi Upton, Barbie Hansen, and Erin Durkin contributed to the original 2012 data reporting effort at USA TODAY.

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Mass killings database reveals trends, details and anguish in every US event since 2006

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The horror and tragedy of mass shootings in American schools, churches and other public places capture the nation's attention. But these are only part of the larger violence of mass killings - deaths by guns, knives, fires, vehicles and other weapons in public and in private - that plague the U.S., research shows.

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"the average age for mass shooters in the modern era is 34 years old. In the last three years, under the sway of the pandemic, that figure has dropped dramatically to as young as 21."

"the previous oldest shooter, who killed five people in Kentucky in a retail store in 1981, was 70."

" the older age of the California suspects was “strikingly rare”"

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As California, and the United States, reel from two devastating mass shootings in three days that have left 18 people dead and many more injured, detectives are combing through the crime scenes in Monterey Park and Half Moon Bay in search of motives.

One aspect they will have to grapple with that makes the California tragedies stand out from the grim pack of American gun massacres is the older age of the shooters. In both cases the alleged killers were in their 60s and 70s, placing them in a very rare group.

On Sunday, Huu Can Tran was found dead in a white van having killed himself after a shooting spree the night before at a Monterey Park dance studio in which he killed 11 people. He was 72.

Then, on Monday afternoon, at two separate locations in Half Moon Bay, south of San Francisco, a gunman opened fire and killed seven people. The suspect, who was arrested and is said to be cooperating with police, Zhao Chunli, was 67.

According to the authoritative database the Violence Project, which tracks all mass shootings in which four or more victims died in a public space, the ages of this week's California suspects put them within the top three individuals recorded in almost 60 years. Of 168 events itemized by the project between 1966 and 2020, the previous oldest shooter, who killed five people in Kentucky in a retail store in 1981, was 70.

Overall, the Violence Project estimates the average age for mass shooters in the modern era is 34 years old. In the last three years, under the sway of the pandemic, that figure has dropped dramatically to as young as 21.

The project's executive director, Jillian Peterson, said that the older age of the California suspects was "strikingly rare".

"This is a stunningly different profile that I did not see coming," she said.

Given the rarity of the subjects, researchers know relatively little about the older perpetrators of mass public shootings. As with any such event in the US, there is always a heightened risk of copycat sprees in the days after a massacre.

That may have been a factor in Half Moon Bay, following soon after the Monterey Park shooting, not only in the nature of the attack itself but also in the suspect's age.

Peterson said that one aspect of the actions of older gunmen - most mass shooters are indeed men, the database suggesting that about 98% are male - was that unlike younger killers they do not appear to be motivated by a desire to propagate any particular ideology or message.

"Older shooters don't seem to leave behind manifestos or videos explaining why they did this, as younger perpetrators often do," Peterson said. "For the younger people, the goal of the shooting is to make a message go out to the world - here's my anger, here's my pain - and they work to make that go viral."

By contrast, such a performance element of the violence is often absent or less evident among the older cohort. "We're not seeing that here," Peterson said.

"In fact, the motive is really confusing. My guess is that it's more interpersonally driven because we're not seeing that broader message."

In addition to the age of the suspects, Californians are left coming to terms with how such a gruesome pair of shooting sprees could happen in a state with some of the most stringent gun control laws in America. A scorecard compiled by Giffords, the gun safety campaign led by the former congresswoman Gabby Giffords who was shot in the head in an attempted assassination in 2011, gives an "A" grade for what it calls commonsense gun laws to only two states - California and New Jersey.

Questions will be asked about how the Monterey Park killer was able to wield a 9mm semi-automatic assault weapon of the type that is strictly banned in California. The tragedy underlines the challenges posed by the patchwork of laws that exist in a country that largely leaves decisions over gun regulation to individual states.

On the other hand, California can continue to draw comfort that despite this week's disasters, its relatively tough approach to gun safety is clearly having a positive impact. According to the Centers for Disease Control, California's rate of death by firearm is 8.5 for every 100,000 people - the seventh lowest in the US.

By contrast, states that pride themselves on their loose approach to gun possession such as Louisiana and Mississippi have firearm death rates of 26.3 and 28.6 for every 100,000 respectively.

Conversely, even California has a disastrous record when it is compared to societies in which guns are not ubiquitous as they are in the US. In continental Europe, about 7,000 people die each year from gunshot wounds.

That's a death rate of just 0.9 for every 100,000 people.

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Older suspects in California shootings defy typical mass shooter profile

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As California, and the United States, reel from two devastating mass shootings in three days that have left 18 people dead and many more injured, detectives are combing through the crime scenes in Monterey Park and Half Moon Bay in search of motives.

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"Men in a younger age range are ... more likely to be impulsive"

"between 1976 and 2018, 82% of all mass shooters in the U.S. were under the age of 45."

"Metzl says that neither gender nor age, at the end of the day, is the most important predictor for gun violence.

"It's access," he said. "The easier it is for people to get guns, the easier it is for people of all age demographics to get into shootings.""

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“77% of those who engaged in mass shootings purchased at least some of their guns legally, while illegal purchases were made by 13% of those committing mass shootings.”

"The project spanned mass shootings over more than 50 years, yet 20% of the 167 mass shootings in that period occurred in the last five years of the study period."

"Sixteen of the 20 deadliest mass shootings in modern history (i.e., from 1966 through 2019), occurred between 1999 and 2019, and eight of those sixteen occurred between 2014 and 2019."

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Public Mass Shootings: Database Amasses Details of a Half Century of U.S. Mass Shootings with Firearms, Generating Psychosocial Histories

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Persons who committed public mass shootings in the U.S. over the last half century were commonly troubled by personal trauma before their shooting incidents, nearly always in a state of crisis at the time, and, in most cases, engaged in leaking their plans before opening fire. Most were insiders of…

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"The two young men accused of carrying out the massacres in Buffalo and Uvalde followed a familiar path: They legally bought semiautomatic rifles right after turning 18, posted images intended to display their strength and menace — and then turned those weapons on innocent people."

"Six of the nine deadliest mass shootings in the United States since 2018 were by people who were 21 or younger, representing a shift for mass casualty shootings, which before 2000 were most often initiated by men in their mid-20s, 30s and 40s."

“We see two clusters when it comes to mass shooters, people in their 40s who commit workplace type shootings, and a very big cluster of young people — 18, 19, 20, 21 — who seem to get caught up in the social contagion of killing,”

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Six of the nine deadliest mass shootings in the United States since 2018 were by people who were 21 or younger, a shift from earlier decades.

A memorial for the victims of Robb Elementary School in Uvalde, Texas, on Wednesday. Credit... Ivan Pierre Aguirre for The New York Times

WASHINGTON - The two young men accused of carrying out the massacres in Buffalo and Uvalde followed a familiar path: They legally bought semiautomatic rifles right after turning 18, posted images intended to display their strength and menace - and then turned those weapons on innocent people.

As investigators and researchers determine how the tragedies unfolded, the age of the accused has emerged as a key factor in understanding how two teenagers became driven to acquire such deadly firepower and how it led them to mass shootings.

They fit in a critical age range - roughly 15 to 25 - that law enforcement officials, researchers and policy experts consider a hazardous crossroads for young men, a period when they are in the throes of developmental changes and societal pressures that can turn them toward violence in general, and, in the rarest cases, mass shootings.

Six of the nine deadliest mass shootings in the United States since 2018 were by people who were 21 or younger, representing a shift for mass casualty shootings, which before 2000 were most often initiated by men in their mid-20s, 30s and 40s.

"We see two clusters when it comes to mass shooters, people in their 40s who commit workplace type shootings, and a very big cluster of young people - 18, 19, 20, 21 - who seem to get caught up in the social contagion of killing," said Jillian Peterson, a criminal justice professor who helped found the Violence Project, which maintains a comprehensive national database of mass shootings.

There is no single, easy explanation for why young men are more likely to engage in mass shootings. (Girls and women make up a small percentage of all perpetrators.) But many of the causes cited most often by law enforcement officials and academics seem intuitive - online bullying, the increasingly aggressive marketing of guns to boys, lax state gun laws and federal statutes that make it legal to buy a semiautomatic "long gun" at 18.

The shootings come against a backdrop of a worsening adolescent mental health crisis, one that predated the pandemic but has been intensified by it. Much of the despair among teenagers and young adults has been inwardly directed, with soaring rates of self-harm and suicide. In that sense, the perpetrators of mass shootings represent an extreme minority of young people, but one that nonetheless exemplifies broader trends of loneliness, hopelessness and the darker side of a culture saturated by social media and violent content.

In addition to Buffalo and Uvalde, Texas, there was a mass shooting at supermarket in Boulder, Colo., in March 2021 that the police said was carried out by a 21-year-old man; a massacre by what authorities said was a 21-year-old gunman targeting Hispanic shoppers at a Walmart in El Paso in August 2019 that resulted in 23 deaths; a school shooting in Santa Fe, Texas, in which a 17-year-old student is accused of killing eight students and two teachers in May 2018; and the killing of 17 people at Marjory Stoneman Douglas High School in Parkland, Fla., in February 2018 by a 19-year-old former student.

Only two of the 30 deadliest mass shootings recorded from 1949 to 2017 involved gunmen younger than 21: The first was the massacre of 13 people by two teenagers at Columbine High School in 1999, and the second came when a 20-year-old killed 27 people, most of them children, at Sandy Hook Elementary School in Newtown, Conn., in 2012.

A shooting on Wednesday in Tulsa, Okla., in which a gunman killed four people and wounded several more before apparently taking his own life, defied the recent pattern. The police said they believed that the gunman, whom they had not identified, was between 35 and 40 years old.

Frank T. McAndrew, a Knox College psychology professor who studies mass shootings, said almost all of the young killers he has researched were motivated by a need to prove themselves.

"These are young guys who feel like losers, and they have an overwhelming drive to show everybody they are not on the bottom," he said. "In the case of the Buffalo shooter, it was about trying to impress this community of racists he had cultivated online. In the case of the kid in Uvalde, it was about going back to the place where you felt disrespected and acting out violently."

Ms. Peterson added: "And since Columbine, they have tended to study and emulate each other. It's a growing problem."

In almost every case, social media or interactive online game platforms played some role, mirroring the ubiquity of online youth culture over the past two decades.

Demonstrators for gun control in Washington holding a vigil last week for victims in Uvalde and Buffalo. Credit... Kenny Holston for The New York Times

In the late 1990s, at the dawn of the social media age, one of the gunmen at Columbine created a blog on AOL to detail his violent thoughts.

The 22-year-old college student who murdered six people in Santa Barbara, Calif., in 2014 offered one of the most direct expressions of a gunman's mentality in a video posted on YouTube: The gun, he said, gave him a sense of power.

The Buffalo gunman, emulating the 28-year-old anti-Muslim terrorist who massacred 51 people in Christchurch, New Zealand, three years ago, live streamed himself as he methodically killed shoppers because they were Black. The man accused of the killings in Uvalde used Yubo, a relatively new platform, to share menacing messages in which he seemed to telegraph his plans.

"It's a way for kids to flex," said Titania Jordan, with Bark Technologies, an online safety company that monitors the use of platforms for violent content. "It's a way for them to show strength if they are bullied, or left out. It's just a part of the narrative now in all these cases - there's always a social media component."

There is also a biological one. Scientists have long known the teenage and post-teenage period is a critical time for brain development and a time, for most teenage boys, often characterized by aggressive and impulsive behavior. Girls of the same age, by contrast, have greater control over their impulses and emotions.

Overall, boys and young men account for half of all homicides involving guns, or any other weapon, nationwide, a percentage that has been steadily rising. Exactly 50 percent of all killings in 2020, the last year comprehensive data is available, were committed by assailants under 30, according to the F.B.I.'s uniform crime data tracking system.

Mass shootings, defined by most experts as involving the deaths of more than four people, are rare; shootings on the scale of Buffalo and Uvalde, with more than 10 victims, are even less common. Around 99 percent of all shootings in the country involve fewer victims, are the result of crime or personal disputes, and are motivated by drug activity, gang conflict, domestic violence and personal disputes, according to statistics compiled by the federal government and academics.

"Why are a disproportionate number of crimes committed by males in their late teens and early 20s?" asked Laurence Steinberg, a professor of psychology and neuroscience at Temple University who has worked extensively on issues involving adolescent brain development.

The explanation, he said, includes the increasingly well-understood neurobiology of the teenage years. During adolescence, a "huge mismatch" develops between parts of the brain that cause impulsive behavior and emotional sensitivity and other parts of the brain that regulate acting out on such impulses, Dr. Steinberg said. Men, he added, tend typically to have an even higher, faster peak in arousal, while women see a higher peak in regulation at an earlier age - and therefore "at every age, males are more sensation-seeking."

The height of that mismatch tends to be in the late teens or early 20s. "Then the regulatory systems start to catch up to the impulses, and you've got this gradual improvement in ability to control thoughts, emotions and behaviors ongoing into the early 20s," Dr. Steinberg added.

The changes in brain development are accompanied by the disorienting societal passage from boy to man, with all the turbulence that entails even in healthy boys. There are "major differences in socialization for males and females related to aggressive behavior, appropriate ways to seek support, how to display emotions and acceptability of firearm use," said Sara Johnson, a professor of pediatrics at the Johns Hopkins University School of Medicine.

Young men are "almost universally" in transition "in their relationships, living situations, lifestyles, education, occupation," while "at the same time they have substantial autonomy from the adults in their lives and may find themselves negotiating with little support or supervision," Dr. Johnson said.

A memorial near the Tops grocery store in Buffalo, where 10 people were killed last month. Credit... Kenny Holston for The New York Times

Yet what differentiates mass killers from other young men who do not act on these impulses is hard to define, and even harder to counter: madness.

Still, the vast majority of young men with mental health disorders, even serious ones, never commit acts of violence. They are more likely to be victims, or impulsively hurt themselves, than to painstakingly plot violence against others.

Republicans, countering Democratic calls for tightened gun controls, have seized on improving school safety and upgrading mental health services after the recent massacres.

Conservatives are also resisting efforts by congressional Democrats to raise the legal age to buy a semiautomatic rifle from 18 to 21. A Republican-appointed federal judge recently struck down California's attempt to increase the age. The state enlisted Dr. Steinberg and other experts to make the scientific case for keeping such weapons out of the hands of teenagers.

Their arguments did not prevail. "America would not exist without the heroism of the young adults who fought and died in our revolutionary army," Judge Ryan Nelson, speaking for a two-to-one majority in the U.S. Court of Appeals for the Ninth Circuit, wrote in an opinion released on May 11, three days before the rampage in Buffalo.

With few policy safeguards, mental health professionals and local authorities have been left to spot and stop potential gunmen, with uneven success.

In 2018, the police arrested two boys, 13 and 14, after receiving a tip just before the anniversary of the Columbine shooting. The teenagers were planning to target a school in Uvalde and wanted to rob a neighbor's house to obtain weapons. The suspect in the Uvalde massacre was not involved in that plot.

Over the years, Jill H. Rathus, a therapist in Great Neck, N.Y., has seen her share of young men who seemed to be a danger to themselves or others, including one whose mother feared her son would become a gunman. He did not.

Dr. Rathus and other experts cautioned that there were vast differences between suicidal and homicidal behavior, but she also said she saw some overlap in certain feelings that contributed to growing acts of violence directed at self and at others. "There's an incredible sense of aching despair plus hopelessness, and then there's a sense of a lack of meaningful connections," Dr. Rathus said. "Then there's access to lethal means, that's the center."

In 2006, Dr. McAndrew, the Knox College psychology professor, and two of his colleagues set out to test the effect of guns on the behavior of young men, monitoring the testosterone levels, and signs of aggression, in 30 male college students when they were given a children's toy and an actual firearm.

"The presence of a gun changed their behavior significantly," he said. "Just holding a gun gave you guts."

Glenn Thrush reported from Washington, and Matt Richtel from San Francisco.

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A Disturbing New Pattern in Mass Shootings: Young Assailants

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Six of the nine deadliest mass shootings in the United States since 2018 were by people who were 21 or younger, a shift from earlier decades. WASHINGTON - The two young men accused of carrying out the massacres in Buffalo and Uvalde followed a familiar path: They legally bought semiautomatic rifles right after turning 18, posted images intended to display their strength and menace - and then turned those weapons on innocent people.

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"The median age of mass shooters in the United States is 32. Yet the man who is alleged to have shot dead 11 people in Monterey Park on Jan. 21, 2023, before turning the gun on himself was 72 years old – the oldest mass shooter in modern American history"

"the gunman who took the lives of seven more in Half Moon Bay two days later was also older than most — 66, the third-oldest in history."

"From 1980 to 1989, the median age of mass shooters was 39. Over the next two decades, it was 33. And from 2010 to 2019, it was 29. Since 2020, the median age of mass shooters has come down to just 22 years old"

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The two men who shot dead 18 people in separate incidents just days apart in California are the latest perpetrators in America's long history of mass gun violence. But something about these public shootings, and the men held responsible, stands out.

The median age of mass shooters in the United States is 32. Yet the man who is alleged to have shot dead 11 people in Monterey Park on Jan. 21, 2023, before turning the gun on himself was 72 years old - the oldest mass shooter in modern American history, our records show. Meanwhile, the gunman who took the lives of seven more in Half Moon Bay two days later was also older than most - 66, the third-oldest in history.

We are criminologists who built a database of 191 mass shooters using public data. The shooters in our records date back to 1966 and are coded on nearly 200 different variables, including age at the time of attack. Our research shows that mass shootings - defined here as events in which four or more people are killed in a public place with no underlying criminal activity - have become more frequent, and deadly, over time.

Prior to the January 2023 Californian shootings, mass shooters were also getting younger overall. From 1980 to 1989, the median age of mass shooters was 39. Over the next two decades, it was 33. And from 2010 to 2019, it was 29.

Since 2020, the median age of mass shooters has come down to just 22 years old - mostly young men and boys who were born into or came of age in an increasingly divided America and carried out their attacks amid the disruption of a global pandemic.

Older mass shooter behind deadliest assault

Ages vary by shooting location, the data shows. Though mass shooters at offices, warehouses and houses of worship skew older, shooters at K-12 schools, colleges and universities tend to be younger - in large part because many school shooters tend to be current or former students.

Prior to the tragic incidents in Monterey Park and Half Moon Bay, just six mass shooters in our study were over the age of 60. The oldest was a 70-year-old who killed five people at an auto parts store in Kentucky in 1981. The list also includes the perpetrator of the deadliest mass shooting in U.S. history - a 64-year-old who killed 60 people at a 2017 music festival in Las Vegas.

The others were a 66-year-old who was supposed to turn himself in to serve a prison sentence but instead killed four people at the manufacturing plant where he used to work in Illinois in 2001; a 64-year-old who killed four barbershop and oil change shop patrons in rural New York in 2013; a 62-year-old who killed four people in 1997 in New Hampshire, including two state troopers and a judge; and a 60-year-old who killed six at a shopping center in Palm Bay, Florida, in 1987.

Nearly all of the over-60s perpetrators of mass shootings prior to the January 2023 Californian incidents were white men - just one was a nonwhite male. This differs in the Monterey Park and Half Moon Bay incidents, both of which are thought to have been carried out by Asian Americans.

Less likely to leak details of attack

Mass shooters over 60 also tend to have prior criminal records and to target their place of employment, or retail and outdoor locations in communities they knew well.

What separates the older mass shooters from their younger counterparts is that mass shooters in their 20s and 30s typically study previous mass shooters for inspiration and validation. Younger shooters also tend to communicate intent to do harm in advance. This practice, known as leakage, is often seen as a final cry for help. Younger shooters also tend to leave behind manifestos to communicate their anger and grievances to the world, the data shows. Analysis of their expressed motives suggest they are seeking fame and notoriety for their actions.

None of the shooters aged 60 and above in our database did that - although investigations are ongoing in the back-to-back California cases. Instead, they tend to have experienced a recent stressor, such as a family conflict or debt. They are more likely to be motivated by legal, financial and interpersonal conflicts, not hate or fame-seeking like many of their younger counterparts.

But all perpetrators of mass shootings, young and old, have some things in common. Their mass shooting is intended to be their final act. Whether they die by suicide - as is seemingly the case with the alleged Monterey Park shooter, are killed on scene, or sit and wait to be arrested like the Half Moon Bay suspect did, mass shootings are a final act of hopelessness and anger.

They also have access to the firearms they need to commit these devastating crimes.

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Typical mass shooters are in their 20s and 30s - suspects in California's latest killings are far from that average

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The two men who shot dead 18 people in separate incidents just days apart in California are the latest perpetrators in America's long history of mass gun violence. But something about these public shootings, and the men held responsible, stands out. The median age of mass shooters in the United States is 32.

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"Research has repeatedly shown that criminal activity increases throughout teen years, reaches its highest point at age 17"

"chronic offenders would be statistically likely to stop committing crime by around the age of 40, Nellis said."

"Brain development isn’t complete until the mid-20s, hindering decision-making that might lead to crime and risky behavior"

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Why older mass shooters like the California gunmen are so rare

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The Monterey Park and Half Moon Bay shooters don’t fit the typical profile of a violent criminal.

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"This database originally covered cases from 1982 to 2012 and has since been updated and expanded numerous times."

"this database does not include... attacks in which fewer than three victims died"

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This database originally covered cases from 1982 to 2012 and has since been updated and expanded numerous times. For analysis and context on this data—including how we built the database, and a change to the baseline for victim fatalities with cases dating from January 2013—see our Guide to Mass Shootings in America, which includes an interactive map documenting all of the cases.

[Editor’s note, 4/24/22: Readers may wonder why this database does not include the New York City subway shooting on April 12, the school shooting in Washington, DC, on April 22, or other such attacks in which fewer than three victims died; for additional context on the challenges of defining and tracking mass shootings, and on our approach, see this piece and this piece.]

You can scan the underlying spreadsheet by clicking here and download the database in its entirety (in CSV format) by clicking here.

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US mass shootings, 1982–2022: Data from Mother Jones’ investigation

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The full data set from our in-depth investigation into mass shootings.