John Wayne Gacy (March 17, 1942 – May 10, 1994) was an American serial killer and sex offender who raped, tortured, and murdered at least 33 young men and boys. Gacy regularly performed at children's hospitals and charitable events as "Pogo the Clown" or "Patches the Clown", personas he had devised. He became known as the Killer Clown due to his public services as a clown prior to the discovery of his crimes.

Gacy was convicted of the sodomy of a teenage boy in Waterloo, Iowa, in 1968 and was sentenced to ten years' imprisonment, but served eighteen months.

He murdered his first victim in 1972, had murdered twice more by the end of 1975, and murdered at least thirty subsequent victims after his divorce from his second wife in 1976.

The investigation into the disappearance of Des Plaines teenager Robert Piest led to Gacy's arres ...