Joseph "Joey" Cantalupo was an American Mafia associate from the Colombo Crime Family and later for being government informant.
Informant
Cantalupo turned informant in 1972 and was a considerable asset to the FBI in prosecuting mafia trials.
He has testified in court, written a book on his activities in organized crime and also appeared in mafia related documentaries (such as Crime Inc. (1984)) as an authority on mafia life.
References
Joseph Cantalupo Wikipedia(Text) CC BY-SA