WHY SAMMY THE BULL TURNED MOB RAT!

Marked for death by Godfather Gotti

THE Mafia's slippery Teflon Don John Gotti finally went to prison after being ratted out by hitman Sammy “The Bull” Gravano who believed the mob boss targeted him for death.

That's the chilling reason Gravano broke the Mafia's code of silence and flipped godfather, according to former crime-busting Deputy U.S. Attorney John Gleeson's bombshell book, The Gotti Wars: Taking Down America's Most Notorious Mobster.

At the time Gravano sold out Gotti in 1987, Gleeson was readying to try the Gambino family boss for murder a second time.

John Gotti was convicted of five murders and sentenced to life without parole

Based on FBI wiretap tapes played at a pretrial hearing, Gravano told Gleeson he believed Gotti wanted him dead because the don "sounds like he's trying... to go along with whacking me.”