Saw this on some music forum but the poster didn't say where he got it from. Hill never tells the same story twice. He was a fucking degenerate idiot.

"When Henry Hill became an FBI informant in 1980, he told authorities that DeSimone had been murdered by the Gambino Crime Family. The full details were unknown until 1994, when Hill, in his book Gangsters and Goodfellas, gave the whole story of the events leading up to DeSimone's death. Hill's wife, Karen, had been having an affair with Hill's boss, Mafia Capo Paul Vario. When Hill was sentenced to prison, DeSimone approached Karen Hill for sex; when she turned him down, DeSimone attempted to rape her. In retaliation, Paul Vario approached the Gambino crew and revealed that DeSimone had murdered Foxy and Billy Batts without first seeking permission from the Gambino family, violating mafia protocol. Sometime in January 1979, DeSimone was contacted and told that he was going to be "made." Peter Varýo and Bruno Facciolo took him to a house, where he was executed."

The same paragraph is on DeSimones wiki page so thats probably where this other guy got it from.