Toole was often designated as suffering from mild mental retardation, with an I.Q. of 75.^[1] He also suffered from epilepsy, which resulted in frequent grand mal seizures. Throughout Toole's childhood, he frequently ran away from home and often slept in abandoned houses. He was a serial arsonist from a young age and was sexually aroused by fire.^[3]

In the documentary Death Diploma, Toole claimed he was forced to have sex with a friend of his father's when he was five years old. He felt he knew he was gay when he was 10, and claimed to have had a sexual relationship with a neighborhood boy when he was 12. Toole dropped out of school in the ninth grade and began visiting gay bars. He also claimed to have been a male prostitute as a teenager, and became obsessed with gay pornography.^[1] Toole claimed to have committed his first murder at the age of 14, when after being propositioned for sex by a traveling salesman, Toole ran over the salesman with his own car.^[1] Toole was first arrested at the age of 17 in August 1964 for loitering.

Much information on Toole between 1966 and 1973 is unclear, but authorities believe that he began drifting around the Southwestern United Statesand that he supported himself by prostitution and panhandling. While living in Nebraska, Toole was one of the prime suspects in the 1974 murder of 24-year-old Patricia Webb. Shortly after, he left Nebraska and briefly settled in Boulder, Colorado. One month later, he became a prime suspect in the homicide of 31-year-old Ellen Holman, who was murdered on October 14, 1974. With many accusations against him, Toole left Boulder and headed back to Jacksonville.

In early 1975, Toole returned to Jacksonville after drifting and hitch-hiking through the American South. On January 14, 1976, he married a woman 25 years his senior. She left him after three days, after discovering his homosexuality. Toole said during an interview his marriage was a tactic meant to conceal his true sexuality.

In December 1949, Lucas' father, Anderson, whose legs had been severed in a railroad accident, died of hypothermia after going home drunk and collapsing outside during a blizzard. Shortly thereafter, while in the sixth grade, Lucas dropped out of school and ran away from home, drifting around Virginia. Lucas claimed to have committed his first murder in 1951, when he strangled 17-year-old Laura Burnsley, who had refused his sexual advances. As with most of his confessions, he later retracted this claim. On June 10, 1954, Lucas was convicted on over a dozen counts of burglary in and around Richmond, Virginia, and was sentenced to four years in prison. He escaped in 1957, was recaptured three days later, and was subsequently released on September 2, 1959.^[4][5]

In late 1959, Lucas traveled to Tecumseh, Michigan to live with his half-sister, Opal. Around that time, Lucas was engaged to marry a pen pal with whom he had corresponded while incarcerated. When his mother visited him for Christmas, she disapproved of her son's fiancée and insisted he move back to Blacksburg. He refused, after which they argued repeatedly during the visit about his upcoming nuptials.

On January 4, 1982, Toole barricaded 64-year-old George Sonnenberg in a boarding house where he was living in Jacksonville and set the house on fire. Sonnenberg died a week later of injuries he sustained in the fire. In April 1983, Toole was arrested for an unrelated arson incident in Jacksonville. For that crime, he was sentenced to 20 years in prison.^[5] While in custody, Toole confessed to killing George Sonnenberg.^[6] Toole signed a confession stating that he and Sonnenberg had begun a sexual relationship and, after the two had an argument, Toole set Sonnenberg's home on fire.^[7]

Two months later in June, his accomplice Henry Lee Lucas was arrested for unlawful possession of a firearm. It was then Lucas began boasting about the murderous rampage orchestrated by the two. At first, Toole had denied involvement but later began backing up Lucas's confessions. Lucas also backed Toole's confession to the murder of Adam Walsh. Journalist Hugh Aynesworth and others investigated for articles that appeared in The Dallas Times Herald. It was calculated that Lucas would have had to use his 13-year-old Ford station wagon to cover 11,000 miles (18,000 km) in one month i.e., around 370 miles (600 km) per day, to have committed the crimes police attributed to him. Lucas became widely regarded as a compliant interviewee who was used by police to clear up unsolved murders that he had not been involved in, aided by Toole giving false statements in collaboration.^[8]

During Toole's trial for murdering George Sonnenberg, Toole claimed that he did not light the home on fire and only signed the confession so he would be extradited back to Jacksonville.^[7] On April 28, 1984, a jury found Toole guilty of first degree murder and sentenced him to death.^[5][6] Later that year, Toole was found guilty of the February 1983 strangulation murder of a 19-year-old Tallahassee, Florida woman, and received a second death sentence; on appeal, however, both sentences were later commuted to life in prison.^{[citation needed]}

After his incarceration, Toole pleaded guilty to four more Jacksonville murders in 1991 and received four more life sentences.