Sells and his twin sister, Tammy Jean, contracted meningitis when they turned 18 months old. While Sells suffered a high fever, he survived. His sister, however, died from the inflammation. Shortly thereafter, Sells was sent to live with his aunt Bonnie Woodall in Holcomb, Missouri. He lived with Woodall until he was five.
When Sells was 8, he began spending time with a man named Willis Clark, from a neighboring city. Clark would later be suspected of child molestation.:4
Sells started traveling to find work. Because he was homeless at the time, he hitched rides, hopped trains and at one point stole a vehicle. He held several different jobs, often doing menial labor.
Sells has claimed he committed his first murder at age 16, on a man who was performing oral sex on a young boy.
In July 1985, when he was 21 years old, Sells was working at a carnival in Forsyth, Missouri. He met Ena Cordt, 35, who had brought her 4-year-old son to the carnival. Cordt invited Sells back to her home that same evening. According to Sells, he had sex with Cordt, but he awoke during the night to find her stealing from his backpack. Seizing her son’s baseball bat, he beat her to death. He also murdered her son because he was a potential witness. The bludgeoned bodies were found three days later, by which time Sells had left town.
In 1997, 10-year-old Joel Kirkpatrick was murdered. His mother, Julie Rae Harper, was convicted of her son’s death, but her conviction was eventually overturned.
In 2002, author Diane Fanning corresponded with Sells. In a letter to Fanning, Sells confessed to murdering Kirkpatrick. In a face-to-face interview with Fanning after the letter was received, Sells said he invaded the home and killed Kirkpatrick because the boy’s mother had been rude to him at a nearby convenience store earlier that night.
Fanning’s testimony before the prisoner review board, according to the Innocence Project, helped get Harper a new trial and, ultimately, an acquittal. Fanning’s resulting book, Through the Window, details Sells’ cross-country crime spree. In 2003, after the publication of Fanning’s book, Harper’s family became convinced that Sells had invaded their home and killed Kirkpatrick.
Sells is also suspected as the perpetrator in the following crimes:
• The murder of Suzanne Korcz in New York during May 1987
• The November 1987 murder of the Dardeen family in Illinois
• The murder of Melissa Tremblay (aged 11) in Lawrence, Massachusetts in September 1988
• Killing a co-worker in Texas during April 1998
• The murder of Katy Harris in Texas in 1999
• The sexual assault and murder of a child, Hailey McComb in Lexington, KY 
Arrests and confessions
Allan B. Polunsky Unit, where Sells is located
Sells has claimed to have killed upwards of 70 people, according to an interview with Columbia University forensic psychiatrist and personality expert Dr. Michael H. Stone in Discovery Channel’s Most Evil.
On December 31, 1999, in the Guajia Bay subdivision, west of Del Rio, Texas, Sells fatally stabbed 13-year-old Kaylene ‘Katy’ Harris 16 times and slit the throat of 10-year-old Krystal Surles. Surles survived and received help from the neighbors. Ultimately, Sells was apprehended using a sketch from the victim’s description.
Tommy Lynn Sells is housed on death row in the Allan B. Polunsky Unit near Livingston, Texas. The TDCJ received him on November 8, 2000. Sells was classified as one of the most violent and dangerous offenders in Texas.