Answer:
Almost none of it is true. Writer/director Tobe Hooper got the idea for the Leatherface character from the real-life serial killer Ed Gein. Ed Gein murdered at least two women, one of whom was found hanging disembowled in his house, and he allegedly engaged in necrophilia and cannibalism with his victims' corpses. He also sewed together a mask and a sort of suit out of his victims' skin.
The similarities between the real-life murders and the movie ends there. Ed Gein did not murder his victims with a chainsaw, nor did he belong to a family of deranged killers. He didn't live in Texas either. He lived in Wisconsin.
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