John Martorano
A notorious hitman, Martorano was at the center of much of the Winter Hill Gang's dirty work in the 1970s. The Milton native has admitted to committing 20 murders between 1965 and 1982, some allegedly at the direction of "Whitey" Bulger and Stephen Flemmi -- or with the gangsters' participation. Martorano cut a deal and served only 12 years and two months in prison and became a free man in March 2007.