Joseph D. Pistone

Joseph Dominick Pistone (born September 17, 1939), also known by his undercover alias Donnie Brasco, is an American former FBI agent.
He worked undercover between September 1976 and July 1981 as part of an undercover job into the Bonanno crime family and the Colombo crime family, two of the Five Families of the Mafia in New York City. 
Pistone was an FBI agent for 17 years, from 1969 until he resigned in 1986. The evidence collected by Pistone led to over 200 indictments and over 100 convictions of Mafia members.