He was convicted and later executed for the rape and murder of 33 boys and young men between 1972 and his arrest in 1978, 27 of whom he buried in a crawl space under the floor of his house, while others were found in nearby rivers. He became notorious as the "Killer Clown" because of the many block parties he threw for his friends and neighbors, entertaining children in a clown suit and makeup, under the name of "Pogo the Clown".
When Gacy was 11, he was struck on the forehead by a swing. The resulting head trauma formed a blood clot in his brain which went unnoticed until he was 16, when he began to suffer blackouts. He was then prescribed medication to dissolve the clot.
After attending four high schools, Gacy dropped out before completing his senior year and left his family, heading west. After running out of money in Las Vegas, he worked long enough to earn money to travel back home to Chicago. Without returning to high school, he enrolled in and eventually graduated from Northwestern Business College. A job selling shoes followed shortly after graduation, and in 1964 the Nunn-Bush Shoe Company transferred Gacy to Springfield, Illinois. In September of 1964, Gacy married Marlynn Myers. He became active in local Springfield organizations, joining the Jaycees and rising to vice-president of the Springfield chapter by 1965.
Gacy's middle class idyll in Waterloo came crashing down in March 1968 when two different Waterloo boys, aged sixteen and fifteen, accused him of sexually assaulting them. Gacy professed his innocence and it appeared he might beat the charges, but in August of that year he hired another Waterloo youth to beat up one of his accusers. Gacy's henchman was caught and confessed all, and Gacy was arrested. Before the year was out he was convicted of sodomy and sentenced to ten years in prison.
Imprisonment was rapidly followed by his wife's petition for divorce. Gacy and his wife were divorced in 1969. He never saw his children again. During his incarceration, Gacy's father died from liver cirrhosis, on Christmas Day 1969. He was paroled in 1970, after serving 18 months. After Gacy was released, he moved back to Illinois to live with his mother. He successfully hid this criminal record until police began investigating him for his later murders.
Gacy moved in with his mother and got a job as a chef in a Chicago restaurant. In 1971, with his mother's financial assistance, he bought a house at 8213 West Summerdale Avenue, in an unincorporated area of Norwood Park Township, Cook County, which is surrounded by the northwest side Chicago neighborhood of Norwood Park. The house had a four-foot deep crawl space under the floor.
On February 12, 1971, Gacy was charged with disorderly conduct; a teenaged boy claimed that Gacy picked him up and tried to force him into sex. The complaint was dropped when the boy did not show up in court. The Iowa Board of Parole did not learn of this and Gacy was discharged from parole in October 1971. On June 22, 1972, Gacy was arrested again and charged with battery after another young man said that Gacy flashed a sheriff's badge, lured him into Gacy's car, and forced him into sex. Again, charges were dropped.
In June of 1972, Gacy married again, to Carole Hoff, an acquaintance from his teenaged years. Hoff and her two daughters moved into the Summerdale home. In 1975, Gacy started his own business, PDM Contractors, a construction company. At the same time, his marriage began to deteriorate. The Gacys' sex life came to a halt, and John would go out late and stay out all night. Carole found wallets with IDs from young men lying around. John began bringing gay pornography into the house. The Gacys divorced in March 1976.
Gacy became active in the local Democratic Party, first volunteering to clean the party offices. In 1975 and 1976 he served on the Norwood Park Township street lighting committee. He eventually earned the title of precinct captain. In this capacity, he met and was photographed with First Lady Rosalynn Carter, who was in town for the annual Polish Constitution Day Parade, held on May 6. Gacy was directing the parade that year, for the third year in a row. Carter posed for pictures with Gacy and autographed the photo "To John Gacy. Best Wishes. Rosalynn Carter". In the picture Gacy is wearing an "S" pin, indicating a person who has received special clearance by the Secret Service. During the search of Gacy's house after his arrest, this photo caused a major embarrassment to the Secret Service.
After Gacy's divorce, the killings began in earnest, and Chicago police would miss several more chances to stop John Gacy. In December of 1976 another Gacy employee, Gregory Godzik, disappeared, and his parents asked police to investigate John Gacy, one of the last people known to have spoken to the boy. But in neither case did the police pursue Gacy and in neither case did they discover his criminal record. In January 1977 John Szyc, an acquaintance of Butkovich, Godzik, and Gacy, disappeared. Later that year another of Gacy's employees was arrested for stealing gasoline from a station; the car he was driving had belonged to Szyc. Gacy said that Szyc had sold the car to him before leaving town, and the police failed to pursue the matter further.
Not all of Gacy's victims died. In March of 1978, Gacy lured Jeffrey Rignall into his car. Gacy chloroformed the young man, took him back to the house on Summerdale, raped and tortured him, and dumped him, alive, in Lincoln Park. Police drew a blank, but Rignall remembered, through the chloroform haze of that night, a black Oldsmobile, the Kennedy Expressway, and some side streets. He staked out the exit on the Expressway until he saw the black Oldsmobile, which he followed to 8213 West Summerdale. Police issued a warrant, and arrested Gacy on July 15. He was still facing trial on a battery charge for the Rignall incident when he was arrested in December for all the other murders. In December 1977, still another victim, a 19-year-old boy, complained that Gacy had kidnapped him at gunpoint and forced him into sex. Yet again, Chicago police took no action.
Gacy's downfall came in December 1978 because of one simple act of carelessness: killing a boy who lived in his own neighborhood. Robert Piest, a fifteen-year-old boy, disappeared on December 11 from the Des Plaines, Illinois pharmacy where he worked after school. Just before he vanished, Piest told a co-worker he was going to a house down the street to talk to "some contractor" about a job. John Gacy had been at the pharmacy that night discussing a remodeling job with the owner. Gacy denied talking to Piest when Des Plaines police called him the next day, but the Des Plaines police did what Chicago police failed to do and checked Gacy's record, discovering that he had done time for sodomy. A search of Gacy's house on December 13 turned up some suspicious items--a 1975 high school class ring, drivers' licenses for other people, handcuffs, a two-by-four with holes drilled in the ends, a syringe, clothing too small for Gacy, and a photo receipt from the pharmacy where Robert Piest worked. Detectives noticed an offensive odor coming from the crawlspace beneath the house.
Further investigation revealed that a Gacy employee, Gregory Godzik, had disappeared. The high school ring was traced to John Szyc, also missing. From Gacy's second wife they learned of John Butkovich, missing since 1975.
On December 21, 1978, one of Gacy's employees told the police that Gacy had confessed to over thirty murders. Shortly thereafter Gacy was arrested for marijuana possession. Police took out a second warrant, went back to the house on Summerdale, and found human bones in the crawlspace. After being informed that he would now face murder charges, Gacy then confessed to some 25-30 murders, telling investigators that most were buried in the crawlspace and on his property and that he threw the last five, after the crawlspace was full, off the I-55 bridge and into the Des Plaines River, including that of Piest. Gacy drew police a diagram of his crawlspace to show where the bodies were buried.
Gacy told the police that he would pick up male teenage runaways or male prostitutes off the streets, and take them back to his house with either promising them money for sex, or just grab them by force. He picked up at least one of his victims at the bus station. Once they got back to his house, he would handcuff them or tie them up in another way. Gacy would often stick clothing in their mouths to muffle their screams. After this, he would choke them with a rope or a board as he sexually assaulted them. Gacy would also keep the bodies with him for as long as decomposition would allow.
The police had already gone back to the house to search for more remains, mostly under the crawlspace. For the next four months, more and more human remains emerged from the house, as reporters, TV news crews, and astonished onlookers watched. Twenty-nine bodies were found in Gacy's crawlspace and on his property between December 1978 and March 1979. The youngest identified victims were Samuel Stapleton and Michael Marino, both 14 years old; the oldest were Russell Nelson and James Mazzara, both 21 years old. Eight of the victims were so badly decomposed that they were never identified. Robert Piest's body was discovered in the banks of the Des Plaines River on April 9.
While on trial, Gacy joked that the only thing he was guilty of was "running a cemetery without a license." At one point in the trial, Gacy's defense also tried to claim that all 33 murders were accidental deaths as part of erotic asphyxia, but the Cook County Coroner countered this assertion with evidence that Gacy's claim was impossible. Gacy had also made an earlier confession to police, and was unable to have this evidence suppressed. He was found guilty on March 13 and sentenced to death.
On May 10, 1994, Gacy was executed at Stateville Correctional Center in Crest Hill, Illinois, by lethal injection. His last meal consisted of a dozen deep fried shrimp, a bucket of original recipe chicken from KFC, a pound of fresh strawberries and French fries. His execution was a minor media sensation, and large crowds of people gathered for "execution parties" outside the penitentiary, with numerous arrests for public intoxication, open container violations, and disorderly conduct. Vendors sold Gacy-related T-shirts and other merchandise, and the crowd cheered at the moment when Gacy was pronounced dead.
According to reports, Gacy did not express remorse. His last words to his lawyer in his cell were to the effect that killing him would not bring anyone back, and it is reported his last words were "kiss my ass," which he said to a correctional officer while he was being sent to the execution chamber.
Before the execution began, the lethal chemicals unexpectedly solidified, clogging the IV tube that led into Gacy's arm, and prevented any further passage. Blinds covering the window through which witnesses observed the execution were drawn, and the execution team replaced the clogged tube with a new one. Ten minutes later, the blinds were reopened and the execution resumed. It took 18 minutes to complete. Anesthesiologists blamed the problem on the inexperience of prison officials who were conducting the execution, saying that proper procedures taught in "IV 101" would have prevented the error. This apparently led to Illinois' adoption of a different method of lethal injection. On this subject, the chief prosecutor at Gacy's trial, William Kunkle, said "He still got a much easier death than any of his victims."
After his execution, Gacy's brain was removed. It is currently in the possession of Dr. Helen Morrison, who interviewed Gacy and other serial killers in an attempt to isolate common personality traits of violent sociopaths; however, an examination of Gacy's brain after his execution by the forensic psychiatrist hired by his lawyers revealed no abnormalities.
The ninth unidentified victim, case file, 959UMIL was identified in June 2007 as Timothy McCoy from Nebraska. McCoy was Gacy's first known and identified victim.
Many of Gacy's paintings were sold at auction after his execution. Nineteen were put up for sale, prices ranging from $195, for an acrylic painting of a bird, to $9500 for a depiction of dwarfs playing baseball against the Chicago Cubs. Some bought Gacy's paintings to destroy them. A bonfire in Naperville, Illinois in June 1994 was attended by 300 people, including family members of nine victims who watched 25 of the paintings burn.