I don't know if anybody has read Killer Fiction by Schaeffer. It's a collection of short stories he wrote filled with his fantasies. It is hard going trying to read them, I don't believe half of what he says but nevertheless he was one sick bastard
Final Truth by Pee Wee Gaskins (Autobiography written by South Carolina's most infamous Serial Killer, incredibly brutal and stomach turning.)
The book is very expensive so the best you can do without spending hundreds is this scan:
Killer Fiction by Gerard John Schaefer, book written by convicted Serial Killer and ex Deputy Gerard Schaefer, which contains some of the most brutal stories that Schaefer would write, that Detectives believe contain details of his actual crimes.
https://www.amazon.com/Killer-Fiction-Stories-Convicted-Ex-Cop-ebook/dp/B003BRBCDS