Thomas Kokoraleis was born in 1961 and raised in the Chicago area within a Greek Orthodox family. He was one of two brothers who would eventually become involved in one of the most brutal and disturbing serial killer cases in Illinois history. Little is publicly documented about Thomas's early life, but at the time of his arrest, he was working as a house painter and had no criminal record.

Psychological evaluations revealed that Thomas had a low IQ—measured around 75—placing him in the borderline range of intellectual functioning. Those who knew him often described him as someone who lacked assertiveness and could be easily influenced. This would later become a central point in his defense, with his attorneys framing him as a vulnerable follower under the command of more dominant personalities, particularly Robin Gecht.

Despite being raised in a religious household, Thomas became entangled in the dark and sadistic world led by Gecht, where twisted rituals, sexual violence, and murder were masked by faux satanic beliefs. His quiet exterior stood in stark contrast to the heinous acts he would later admit to during police interrogations.

Thomas Kokoraleis was a key member of the infamous Ripper Crew—a satanic cult-style killing group active in Chicago from 1981 to 1982. The group, led by Robin Gecht and including Edward Spreitzer and Andrew Kokoraleis (Thomas's brother), terrorized the Chicago area, preying on women in some of the most vicious and ritualistic murders in U.S. history.

Their rampage began with the abduction and mutilation of Linda Sutton in May 1981. Her body, with the left breast amputated, was discovered behind a motel. For the next year, the group abducted, tortured, sexually assaulted, and killed multiple women, often removing one or both breasts as part of their so-called "satanic rituals." Survivors of some attacks—such as Angel York and Beverley Washington—would later help authorities identify their attackers.

Thomas Kokoraleis was arrested on November 12, 1982, after Gecht’s van was linked to the attempted murder of Washington. During police interrogation, Thomas gave chilling confessions, describing how the victims were taken to Gecht’s home, which he referred to as a “satanic chapel.” There, the women were raped, mutilated, and sometimes cannibalized. Thomas described Gecht keeping severed breasts in a box and performing disturbing rituals that included sexual acts with the body parts.

Thomas confessed to participating in the 1982 murder of Lorraine Borowski, a young woman who was abducted outside her work and later found raped, mutilated, and murdered. He was convicted in 1984 and sentenced to life in prison. However, his rape conviction was overturned on appeal, and he was granted a new trial. To avoid facing trial again, Thomas entered a plea deal in which he pled guilty to Borowski's murder in exchange for a 70-year sentence. Charges in other murders, including Linda Sutton’s, were dismissed as part of the deal.

Initially scheduled for parole in 2017, his release was delayed due to lack of an approved residence. He was eventually released from prison on March 29, 2019, after serving 37 years. The announcement of his release sparked public outrage, with many protesting his return to society. In a TV interview after his release, Thomas denied being a monster and proclaimed his innocence, despite his earlier detailed confessions.

As of August 2024, Thomas Kokoraleis is living in Peoria, Illinois. His release remains a controversial topic in Illinois, with many still questioning the justice of allowing a self-admitted participant in serial murders to walk free.