Chicago-area contractor John Wayne Gacy leads a double-life as a serial killer, while detectives piece together clues that lead to a shocking discovery.

Chicago-area contractor John Wayne Gacy leads a double-life as a serial killer, while detectives piece together clues that lead to a shocking discovery.

Chicago-area contractor John Wayne Gacy leads a double-life as a serial killer, while detectives piece together clues that lead to a shocking discovery.

Chicago-area contractor John Wayne Gacy leads a double-life as a serial killer, while detectives piece together clues that lead to a shocking discovery.

Chicago-area contractor John Wayne Gacy leads a double-life as a serial killer, while detectives piece together clues that lead to a shocking discovery.