Joseph “Big Joey” Massino, the only mafia boss ever to become a government informant, is set to testify in the murder and racketeering trial of Vincent “Vinny Gorgeous” Basciano.

The former boss of the New York-based Bonanno crime family was found guilty of capital murder on Monday for the 2004 slaying of a mafia associate. Vincent Basciano, 51, known as "Vinny Gorgeous ...