Stephen J. Flemmi

Bulger's front man, "The Rifleman," collected money from bookies and inspired fear in those who didn't pay on time. Arrested in 1995, he fought charges on grounds that the FBI had granted him permission to commit certain crimes short of murder while he worked as an informant. A judge ruled that the gangsters had received no promise of immunity, and Flemmi was sentenced in August 2001 to 10 years. Flemmi also pleaded guilty in 2004 to 10 murders.