Martorano testified for several days in the two-month trial, which concluded at U.S. District Court Monday after a jury found Bulger responsible for 11 murders, and also convicted him of racketeering. Martorano has confessed to 20 murders, which he said he did on behalf of Bulger's former Winter Hill Gang.
Martorano broke his silence in 1998. And he was interviewed at length by 60 Minutes, a move that Carr said infuriated Bulger. Carr wrote a book on Martorano, "Hitman."