What Was John Wayne Gacy’s ‘Mark’? The Serial Killer Left Something Behind In Each Of His Victims

In the late 1970s, the remains of two young men — Timothy O’Rourke and Frank Landingin — were found washed ashore the riverbanks of Grundy County, Illinois with pairs of underwear lodged down their throats. 

In both cases, investigators found no other evidence on the bodies, and they zeroed in on the underwear as their only lead. 

“The question is, why is that foreign material in the throat?” FBI Criminal Profiler Mark Safarik told “Mark of a Killer,” airing Saturdays at 7/6c on Oxygen. “That's a very unusual activity.” 

Authorities were stumped, and it was not until the disappearance of 15-year-old Robert Piest in December 1978 that they got their first big break.  

Piest vanished from his job at a local Des Plaines pharmacy after telling his mother as well as his co-worker that he was leaving to speak with a contractor, who had built some shelves at the store, about a holiday job. He was never seen again. 

Investigators learned the contractor was John Wayne Gacy, a well-liked community man who ran successful businesses and worked as a precinct committee member for the Democratic party.  

“He was a nice guy, the kind of guy you would probably want to have a beer with,” Cook County Assistant State’s Attorney Lawrence D. Finder told “Mark of a Killer.” “He would dress up in a clown costume. He would do charity events as Pogo the Clown.”

While Gacy agreed to meet investigators at the precinct to discuss Piest’s disappearance, he didn’t show up until 3 a.m., and he was wearing clothes covered in dirt, explaining that his car had gotten stuck in the mud near his home.  

Gacy claimed that he had never met or spoken with Piest, but authorities were suspicious. When they drove by his home the next day, they found no evidence that his vehicle had ever been trapped. 

“We knew he lied about that,” State’s Attorney’s Office Investigator Greg Bedoe told “Mark of a Killer.” 

Digging into his background, investigators discovered that Gacy had a sodomy conviction in Iowa a few years prior and was sent to prison for having sexual relations with a juvenile boy, said Des Plaines Police Department Detective Mike Albrecht. 

They also uncovered that Gacy had been mentioned in Chicago police reports regarding the disappearance of two teenagers — John Butkovich and Gregory Godzik— who had both been employed by Gacy. 

Gacy was immediately put under 24/7 police surveillance, and one day, he made a mistake that broke the investigation wide open. 

“Gacy was arrogant. He could see the policemen sitting in the front of his house. He’d invite them in to use the restroom,” Finder said. 

While one officer was in Gacy’s bathroom, he noticed the unmistakable smell of human decomposition coming up through the heating vent. Authorities drafted a search warrant for the house, and during the canvass, they found a total of 29 bodies.  

Twenty-six were hidden in a crawl space beneath the home, and three others were buried on other parts of the property. Hidden in the rafters of the crawl space, investigators located the jacket that Piest was wearing at the time of his disappearance. 

A bond slip issued to Landingin was also discovered at Gacy’s home, officially connecting him to the murder.  

Analyzing the remains for forensic evidence, pathologists found a familiar mark: fabric stuffed down the victims’ throats in the form of “underwear, socks, rags, tee shirts, pieces of cloth,” said Bedoe. 

“The existence of those materials that was stuffed in the orifices in both the river bodies and the other bodies recovered from the home tied it absolutely to him,” Cook County Assistant District Attorney William J. Kunkle, Jr. told “Mark of a Killer.” 

On Dec. 21, 1978, 36-year-old Gacy was arrested and ultimately charged with 33 counts of murder, including the killing of James Mazzara, whose body was found in the Des Plaines River just days later, and Piest, whose remains were found on an Illinois riverbank in 1979.  

Fabric was found lodged in both young men’s throats. 

Gacy was found guilty on all counts, and 12 of the verdicts qualified for the death penalty. On May 9, 1994, he was executed by lethal injection. 

To this day, six of his victims remain unidentified. 

Watch “Mark of a Killer” now on Oxygen to hear more.