Usually when a horror film claims to be “based on a true story” you can easily assume that it was not. 9 times out of 10, horror movies use this tagline as a marketing ploy to put butts in theater seats. However, for every Paranormal Activity that is steeped in complete fiction there is a film like Texas Chainsaw Massacre that was actually inspired by true events.

1974’s Texas Chainsaw Massacre was based on serial killer Edward Theodore Gein. A Wisconsinite, Gein has been Hollywood’s go-to serial killer for decades. Inspiring movie murderers like Norman Bates from Psycho and Buffalo Bill from Silence of the Lambs. In particular, Bates, Bill, and Texas Chainsaw Massacre’s Leatherface all took a page from Gein’s disturbing hobby of repurposing human flesh to make face masks for himself.

But Gein’s bizarre story doesn’t begin there. As you’ll witness in the following documentary special, the infamous graverobber and murderer had influences of his own. Motivations that paint an even more disturbing picture…