Joe Pistone (alias Donnie Brasco) was an FBI agent who went undercover and infiltrated the Mafia's Bonanno family in the 1970s.
Following his extraction from the mafia, Pistone entered the Witness Protection Program and assumed a new identity. An open contract remains for his death.
He is the subject of the movie Donnie Brasco, where he was portrayed by actor Johnny Depp.