Gacy was a model prisoner and, despite his decade-long sentence, was released on good behavior after only 18 months. He returned to his hometown of Chicago, where he started a contracting business, remarried and volunteered. But after his second marriage failed, things took a turn for the worse. Gacy began abducting boys and young men, raping and murdering them.
Police didn't suspect Gacy until 1978, when witnesses reported that Gacy was the last person to be seen with a missing 15-year-old boy. Investigators questioned Gacy, who admitted to throwing five bodies into a nearby river and drew a map detailing where more than 25 bodies were buried in a crawl space under his home.
Gacy was found guilty of 33 murders. He received the death penalty and was executed by lethal injection in 1994.