A former hitman who admits killing 20 people is expected to take the stand at the trial of reputed gangster James "Whitey" Bulger in Massachusetts.
John Martorano served a little over 12 years in prison after striking a cooperation deal with prosecutors. He was released in 2007.
The 83-year-old Bulger is charged in a 32-count racketeering indictment that accuses him of participating in 19 murders in the 1970s and '80s. He is also charged with extorting bookmakers, drug dealers and others running illegal businesses.
