A clown going around killing people is the stuff of nightmares, so it's no surprise that John Wayne Gacy and his heinous crimes still have the power to shock and appall.
The former KFC manager killed 33 men in the 1970s, and also moonlighted as a clown, called Pogo or Patches, performing at local charity events, parades, store openings and hospitals to entertain sick children.
And while it is disputed if he was ever dressed as a clown when he killed his victims, like all funnymen he always had a trick or two up his sleeve - although his were used to kill. One involved tightening a rope with a hammer handle, throttling his victim, the other involved handcuffs.
But how did John Wayne Gacy become Pogo The Clown?
As part of a fascinating tell-all with The New Yorker magazine in 1994, he shared some written memoirs about his life, and it was within these writings he shared the origins of his now infamous moniker.
He wrote: "I took up the name Pogo and the reason was based on, one, that I was Polish, so that’s where the Po, for Poles, and since I was on the go all the time, I took go and added it to it.”
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Pogo's make-up was a plain white face, oversized red lips and big blue beehive-shaped eyes.
In 1992 he spoke to an FBI investigator about how he found wearing the circus garb "relaxing".
He said: "The clowning was relaxation for me, I enjoyed entertaining kids. Some people unwind different ways, they go out drinking. I would put on clown make-up and could relax."