Twelve of Gacy's identified victims. From top to bottom: John Butkovitch, 17 John Szyc, 19 Randall Reffett, 15 John Mowery, 19 Sam Stapleton, 14 Rick Johnson, 17 William Carroll, 16 Matthew Bowman, 19 Russell Nelson, 21 Darrell Sampson, 18 Gregory Godzik, 17 Robert Piest, 15

  • 1972: Timothy Jack McCoy
    • On January 2, 1972 Gacy picked up a 15 year old youth named Timothy Jack McCoy from a Chicago Greyhound bus terminal. McCoy was from Michigan traveling on a sightseeing tour of Chicago. Gacy drove McCoy to his home promising that he could spend the night and be dropped off at the bus terminal in the morning on time to catch the bus. Gacy later stated that "he awoke the following morning to find McCoy standing in his bedroom doorway with a kitchen knife in his hand." Gacy leapt from his bed and McCoy raised both arms in surrender, while at the same time tilting the knife upwards and accidentally cutting Gacy's forearm. After a brutal brawl, Gacy gained control of the situation by wrestling McCoy to the floor and stabbing him repeatedly in the chest while straddling him with his body. Later Gacy walked into his kitchen seeing an open carton of eggs and a slab of unsliced bacon, McCoy had also set the kitchen table for two; he had went to Gacy's room to wake him while "absentmindedly" carrying the kitchen knife in his hand. Gacy burried McCoys body in the crawl space and later covered the youth's grave with concrete.
  • 1975: John Butkovitch
    • Three Years later on July 19, 1975 17-year-old John Butkovitch, one of Gacy's Employees disappeared. One day prior to his disappearance, Butkovitch threatened Gacy over an issue regarding two weeks of outstanding back pay. While Gacy's wife and stepchildren visiting his sister in Arkansas, he admitted to luring Butkovitch to his home to discuss the issue of the overdue wages. Gacy conned the youth into cuffing his wrists behind his back, then strangled him to death and buried his body under the concrete floor of his garage. Later Gacy admitted to have "sat on the kid's chest for a while before killing him". Butkovitch's Dodge sedan was found abandoned in a parking lot with the youth's wallet inside and the keys still in the ignition. Over the following three years, Butkovitch's parents called police more than 100 times, urging them to investigate Gacy further.
John Butkovitch
  • 1976: Gregory Godzik
    • In December 1976, another Gacy employee, Gregory Godzik, disappeared. While working for Gacy, Godzik informed his family that Gacy had him "digging trenches for some kind of drain tiles" in the crawl space beneath his home. As Godzik's parents and older sister, Eugenia, contacted Gacy about Greg's disappearance, Gacy claimed to the family that Greg had run away from home, having indicated to Gacy prior to his disappearance that he wished to do so. Gacy also claimed to have received a recorded answering machine message from Godzik shortly after the youth had disappeared. When asked if he could play back the message to Godzik's parents, Gacy stated that he had erased it.

Gregory Godzik
  • 1977: Robert Donnelly
    • On December 30, 1977, Gacy abducted at gunpoint 19-year-old student, Robert Donnelly from a Chicago bus stop. Gacy drove Donnelly home with him, raped him, tortured him with various devices, and repeatedly dunked his head into a bathtub filled with water until he passed out, before Gacy revived him. Donnelly later testified at Gacy's trial that he was in such pain that he asked Gacy to kill him to "get it over with", to which Gacy replied: "I'm getting 'round to it". After several hours of assaulting and torturing the youth, Gacy drove Donnelly to his place of work, removed the handcuffs from the youth's wrists, and released him. Donnelly reported the assault and Gacy was questioned about it on January 6, 1978. Gacy admitted to having had "slave-sex" with Donnelly, but insisted everything was consensual. The police believed him and no charges were filed.

  • 25 Identified Victims, 8 Unidentified
    • Timothy McCoy (15) January 3, 1972
    • John Butkovitch (17) July 29, 1975
    • Darrell Sampson (18) April 6, 1976
    • Randall Reffett (15) May 14, 1976
    • Samuel Stapleton (14) May 14, 1976
    • Michael Bonnin (17) June 3, 1976
    • William Carroll (16) June 13, 1976
    • Rick Johnston (17) August 6, 1976
    • Kenneth Parker (16) October 24, 197
    • Michael Marino (14) October 24, 1976
    • Gregory Godzik (17) December 12, 1976
    • John Szyc (19) January 20, 1977
    • Jon Prestidge (20) March 15, 1977
    • Matthew Bowman (19) July 5, 1977
    • Robert Gilroy (18) September 15, 1977
    • John Mowery (19) September 25, 1977
    • Russell Nelson (21) October 17, 1977
    • Robert Winch (16) November 10, 1977
    • Tommy Boling (20) November 18, 1977
    • David Talsma (19) December 9, 1977
    • William Kindred (19) February 16, 1978
    • Timothy O' Rourke (20) June 16–23, 1978
    • Frank Landingin (19) November 4, 1978
    • James Mazzara (21) November 24, 1978
    • Robert Piest (15) December 11, 1978