On Wednesday, Ponzo was convicted of racketeering conspiracy, murder conspiracy in aid of racketeering, firearm possession in relation to murder conspiracy, conspiracy to distribute cocaine, conspiracy to distribute marijuana, loansharking, being a fugitive from the law, money laundering, and attempted witness tampering, the Boston Herald reported.
Prosecutors said Ponzo, a hit man for the Boston Mafia, attempted and failed to kill New England mob boss Francis P. Salemme in 1989, and Joseph Cirame in 1994.
Both victims were shot and seriously injured.
Ponzo disappeared in 1994 after failing to appear in court on drug charges.
He was discovered in Idaho in 2011, working as a rancher under the name "Jay Shaw."
A sentencing hearing in the case has been scheduled for March 6.