Terry Sullivan

Terry Sullivan served as the lead prosecutor in the trial of serial killer John Wayne Gacy in Cook County, Illinois. Sullivan's full name appears in official court records and his 1983 publication detailing the case. He is consistently referenced as Terry Sullivan across investigative reports and media accounts from the era.¹

Terry Sullivan worked as an assistant state's attorney in Cook County, Illinois, building a career in prosecuting major criminal cases during the late 1970s. His role involved coordinating with local law enforcement agencies, including the Des Plaines Police Department and Chicago, on multi-jurisdictional investigations. Sullivan's background positioned him to handle complex prosecutions involving organized crime elements and high-profile defendants in the Chicago area.¹

Role in Prosecution

Terry Sullivan led the prosecution of John Wayne Gacy, securing a conviction in March 1980 on 33 counts of murder after a trial that began in February 1980. He presented evidence from the discovery of 29 bodies in Gacy's crawlspace and four more in the Des Plaines River, emphasizing Gacy's methods of luring young men through his construction company and using handcuffs and torture devices. Sullivan collaborated closely with Des Plaines Police Captain Joseph Kozenczak throughout the investigation, overseeing Gacy's interrogation where confessions implicated accomplices like David Cram and Michael Rossi in body disposal.¹

Terry Sullivan obtained Gacy's death sentence following the 1980 conviction, marking one of the largest serial murder cases in U.S. history at the time. In 1983, Sullivan published The Killer Clown, an authoritative account of the prosecution based on trial evidence, Gacy's confessions, and investigative details from the search warrants executed in December 1978. Sullivan inspected and verified Painting Decorating Maintenance payslips and documents linking Phillip Paske to Gacy's company during a 2016 WGN interview with host Larry Potash, confirming employment dates of September 12, 19, and 25, 1978.¹

Connections

Terry Sullivan worked directly with Joseph Kozenczak of the Des Plaines Police Department, coordinating the second search warrant on December 21, 1978, that uncovered remains in Gacy's crawlspace and led to the arrest. He prosecuted John Wayne Gacy for the murders, including that of victim Robert Piest, while maintaining ongoing contact with Chicago for evidence from Gacy's home, such as driver's licenses of the deceased and a torture board. Sullivan's case involved survivor testimony from Jeff Rignall, who detailed Gacy's 1978 assault involving chloroform and the presence of at least one other individual.¹