WAYMART, Pa. - A convicted mobster who testified for Mafia heir John “Junior” Gotti is dead after prison officials say he was hurt in a fight with another inmate at a Pennsylvania federal prison.

A spokeswoman for the high-security prison in Waymart says Joseph O’Kane, 43, was pronounced dead early Monday  morning from injuries sustained in a housing unit fight the previous night.

advertisement | advertise on newsday

The prison says the FBI is investigating.

The facility was locked down after the altercation, but resumed
normal operations later Monday morning.

O’Kane was serving a life sentence for racketeering and murder.

He testified for the defense in October in a federal racketeering case against Gotti that ended in a mistrial.