Gacy was executed in 1994 after his 1978 conviction for 33 murders.
For several months, Cook County Sheriff Tom Dart has been trying to get prosecutors to approve a warrant for the housing complex search warrant, but State's Attorney Anita Alvarez wanted more evidence, other than the fact Gacy's mother used to live there.
Site Previously Searched
Dart's investigators turned up records showing that Gacy had done handyman work around the complex and witnesses said they saw him around the apartments at odd hours of the day.
Sheriff's spokesperson Frank Bilecki said investigators would initially use thermal imaging devices and cadaver dogs to search underneath the apartments.
"It should initially be pretty non-invasive," Bilecki told reporters.
Bilecki said the apartment complex site was previously searched in 1998 and police found more than a dozen "anomalies" in the dirt under the apartments. He said for some reason, those sites were not investigated further at the time.
John Wayne Gacy the 'Killer Clown'
What Is Your Opinion?
Discuss The John Wayne Gacy Case
Photo: Mug Shot