As outlined by Crime+Investigation UK, investigators working to uncover the circumstances behind the disappearance of 15-year-old Robert Piest began to suspect John Wayne Gacy after receiving information that Gacy "had apparently offered a job to the boy immediately before his disappearance." A search warrant for his home was granted after police discovered that Gacy had a criminal record and was previously sent to prison for sodomy — his crime today would be categorized as sexual assault — in 1968.
"Gacy was placed under 24-hour surveillance and neighbors were questioned. Forensic evidence finally linked one of the rings found during the search to the missing boy, John Szyc," states the same source. It was this match and suspicions arising from a stench in the area that led to a more extensive search, which uncovered the remains of 29 of Gacy's victims on his property, according to History. On December 22, Gacy confessed to the murders and also admitted responsibility for the killings of four more victims whose bodies were discovered in a nearby river.
At his trial in 1980, the killer was sentenced to death. In 1994, after a 14-year stretch on death row, Gacy was finally executed by lethal injection, per History. According to NBC News, John Wayne Gacy: Devil in Disguise suggests that Gacy may have had more victims than are currently known about.
