Thomas Dillon was born in Canton, Ohio, and grew up in the nearby town of Magnolia. He lived there with his wife and son. For twelve years, he worked as a draftsman at the Canton Ohio Waterworks.

Dillon went to college at Ohio State University. He graduated in 1972 with a degree in journalism. This means he studied how to write news stories and other articles for newspapers and magazines. Despite his education and job, Dillon’s life took a dark turn later on, which led to some very troubling actions.

Between April 1, 1989, and April 5, 1992, Thomas Dillon killed five people in Ohio. His fourth victim, Claude Hawkins, was shot on federal property, bringing in the FBI to help with the investigation. This involvement led to Kevin Loring's death being reclassified from an accident to a homicide. Dillon’s last victim, Gary Bradley, was shot just ten days after the task force met. Dillon was later identified as a suspect when a friend reported him after hearing the task force's initial press release.

Dillon’s friend from high school, Richard Fry, contacted investigators in August 1992 after a press conference seeking public leads. Fry described Dillon's suspicious behavior, like shooting at store windows, street signs, and cars. Dillon was then placed under surveillance and was seen burning buildings and killing animals, with an aviation unit also monitoring him. This led to increased scrutiny of his actions.

Dillon was arrested on November 27, 1992, for buying a handgun despite being prohibited from owning firearms. Earlier, in July 1992, he had been placed on probation for possessing an illegal silencer. A search of his home revealed no weapons or ammunition, so authorities asked the public for help. A tip led to a Swedish Mauser rifle that was confirmed by the FBI to match the weapon used in Bradley's murder and was strongly linked to Hawkins' death. Dillon eventually confessed to the murders after the death penalty was taken off the table.

On July 12, 1993, he pleaded guilty and was sentenced to five consecutive terms of thirty years to life for aggravated murder, serving his time at the Southern Ohio Correctional Facility. Dillon's known victims were Donald Welling, Jamie Paxton, Kevin Loring, Claude Hawkins, and Gary Bradley. He was also suspected in the unsolved 1984 shooting of John Joseph Harvat in Pennsylvania and the 1990 murders of Doug Estes and Jim Bennett in Michigan. Dillon never cooperated with the police regarding these additional cases. Dillon died on October 21, 2011, in prison after being hospitalized for nearly three weeks due to an unspecified illness.