The characters and events covered in these 3 films :
- Psycho (Norman Bates)
- The Texas Chainsaw Massacre (Leatherface & clan)
- Silence Of The Lambs (both Hannibal Lecter and Buffalo Bill characters)
were all based on a single man in real life.
This mans name was
Ed Gein.
(The real Ed Gein upon his arrest)
Also, specifically about Ed Gein himself, there was
Ed Gein (2000) starring Steve Railsback as Ed.

Railsback is a superb actor who also gave a chilling performance in the 1970's as Charles Manson in the 1976 film
Helter Skelter.

There are documentaries on Ed as well (check YouTube).
Be warned.....when Googling....images are extremely graphic and not for work or sensitive viewers.
Edited by Man Of Lint - 2/7/13 at 9:14pm