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," is already serving a life sentence for a 2001 murder and now faces the prospect of the federal death penalty when he is sentenced.
The jury in U.S. District Court in Brooklyn found Basciano guilty of ordering the shooting of Mafia associate Randolph Pizzolo.
Basciano's case drew attention last month when another former Bonanno family boss, Joseph Massino, testified how he secretly taped Basciano discussing the murder.
Massino's appearance marked the first time a mafia chieftain testified against an underling, prosecutors said.
Massino testified that he secretly recorded Basciano discussing the Pizzolo murder when both men were behind bars.
"He told me that he killed him," Massino said. "He said he was a scumbag, a rat, a troublemaker."
Prosecutors allege that Basciano ordered Pizzolo killed to send a message to other members of the crime family that Basciano was firmly in charge.
Basciano, who became acting Bonanno family boss in 2004 during Massino's racketeering trial, was tried before for Pizzolo's murder.
That 2007 trial ended in a mistrial, but Basciano was convicted separately of racketeering charges.
The jury will now hear arguments on whether Basciano should be executed or be given another life sentence.