Good point Terence but I think that Anthony Arillotta springfield capo and genovese rat could be a goo example:

http://aboutthemafia.com/tag/anthony-arillotta

He was charged with the murders of former Massachusetts mob boss Adolfo Bruno and mob associate Gary Westerman back in 2003. After cozying up to New York mob leaders and the 2003 murder of his one time mentor Arillotta formerly became a made member of the Genovese family and took over the mob families Springfield operations.