It's not a true story at all.

The "Leatherface" character was inspired by a guy called Ed Gein.

Ed made a habit of luring women and killing them, then treating the skin and wearing it. He was caught in 1957 after a local shop keeper went missing and spent the rest of his life in prison. He died in 1984.

He was a fucked up guy, the 'wearing skin' stuff is the only thing that rings true from the 'Chainsaw' flicks mate