OJ Simpson is said to have paid gangsters from one of history's most maniacal mafia mobs to slaughter his ex-wife Nicole Brown

A key police witness in Simpson's criminal case has now said Simpson was at the scene of Nicole and Ron's killings along with four mobsters from the Gambino crime family he says Simpson paid to kill Nicole.

John Dunton, 62, said in an interview with Hollywood private detective Paul Barresi, 75, when asked if Simpson paid the mob to kill his ex-wife: "100%. The four guys that came, they were members of the Gambino family.

"They were involved in all kinds of stuff. You know what the mob does.

"The bottom line is everything was done with OJ's direction. That's what happened."

Paul has been a private detective for celebrities including Sharon Stone and Amber Heard, and played a tape of his chat with John to the New York Post.

John added in the recording: "He was there. I don't know what he did, but he was there. He knew these guys were going over to Nicole's house to kill her.

"He wanted to be there. I don't know why."

John said about Simpson's death: "I'm glad he's dead to be honest. What he did was a really horrible thing and I went through hell because of that."

Nicole was stabbed seven times in the neck and scalp so severely medical examiners said she was almost decapitated.

John spoke to LA police after Nicole and Ron's double murder, but said he went quiet after mobsters shoved him to his knees, forced a gun into his mouth and threatened to murder him and his family if he spoke about the murder again.

He told Paul: "The guy that put the gun in my mouth, he whacked several people and if he whacked me it wouldn't be any different.

"He also said they'd whack my family too. When they threw me down on my knees and made me cross my ankles over and put a gun all the way down my mouth, it was scary."

John says he refuses to reveal the name of the gangster who threatened him as the mobster is allegedly still alive.