John Wayne Gacy Jr. was a criminal.
John Wayne Gacy Jr. ( March 17 , 1942 -- May 10 , 1994 ) was an American serial killer and rapist . All of Gacy 's known murders were committed inside his Norwood Park ranch house . Convicted of 33 murders , Gacy was sentenced to death on March 13 , 1980 for 12 of those killings . A serial killer is typically a person who murders three or more people , usually in service of abnormal psychological gratification , with the murders taking place over more than a month and including a significant break ( a `` cooling off period '' ) between them .