Gacy committed most of his murders between 1976 and 1978, as he largely lived alone following his divorce. His conviction for thirty-three murders (by one individual) then covered the most homicides in United States legal history.

Gacy murdered one additional unidentified youth and buried him in the crawl space in the spring or early summer of 1977. Gacy drove him to his home, where he raped, tortured, and repeatedly drowned Donnelly to unconsciousness in a bathtub as he made statements such as, "Aren't we playing fun games tonight? McCoy was on his way to his father's home in Omaha, Nebraska, and informed Gacy his bus to Nebraska was not due until noon. J. Simpson, there was a trial of the century which was arguably more grotesque than the other two combined, especially when considering the body count .

When questioned by police, Gacy said Butkovich and two friends had arrived at his house demanding the overdue pay, but they had reached a compromise and all three had left.

The officers then overheard sections of a hushed conversation between Gacy and the two during which Rossi asked Gacy, "And what? In the sentencing phase of the trial, the jury deliberated for more than two hours before sentencing Gacy to death for each murder committed after the Illinois statute on capital punishment came into effect in June 1977. In 1971, Gacy established a part-time construction business, PDM Contractors (for "Painting, Decorating, and Maintenance"). The original identification of the body has been disputed because the exhumed body had neither an upper nor lower jaw bone. The film is based largely on the investigation of Gacy following the disappearance of Robert Piest, by Des Plaines Police.Was it his alcoholic, abusive father or was it something deep within him that caused the seemingly normal Gacy to sexually assault, torture and murder at least thirty-three young men and boys?

Twenty-six victims were buried in the crawl space of his home, and three were buried elsewhere on his property; four were discarded in the Des Plaines River.Less than four weeks later, Gacy murdered 16-year-old Robert Winch and buried him in the crawl space. He was tried in Cook County, Illinois, before Judge Louis Garippo; the jury was selected from Rockford because of extensive press coverage in Cook County. However, the sheriff's office noted that in 1998, a radar survey suggested fourteen areas of interest within the grounds, yet only two of these had been excavated; four of those remaining were described as being "staggeringly suggestive" of human skeletons. This program focuses on the consultation between Detective Joseph Kozenczak and psychic Carol Broman, whom Kozenczak had met on December 17, 1978, to discuss the whereabouts of the body of Robert Piest.