A Roxbury native, Stephen J. Flemmi got his nickname during the Korean War, when he was an uncanny marksman in the Army. In the 1960s, Flemmi developed close ties to both the Irish and Italian mobs, befriending Mafia boss Francis "Cadillac Frank" Salemme and earning a reputation as a cold-blooded operative. He later joined up with Somerville's Winter Hill gang, where he forged a close partnership with "Whitey" Bulger. Flemmi served as Bulger's front man, collecting money from bookies and inspiring fear in those who didn't pay their debts on time. He began informing for the FBI several years before his boss.

Flemmi was arrested in 1995 on charges of racketeering and extortion, but fought the charges on grounds that the FBI had granted him and Bulger permission to commit certain crimes short of murder while they worked as informants. The ensuing court hearings dredged up some of the Boston FBI’s darkest secrets, including revelations of agents accepting payoffs and leaking information to help protect Flemmi and Bulger from prosecution. A judge ultimately ruled that the gangsters had received no promise of immunity, and Flemmi was sentenced in August 2001 to 10 years in prison for extortion and money laundering as part of a plea agreement with prosecutors. However, the deal did not resolve the most serious charges against Flemmi; he still faces 10 federal murder charges and state murder charges in Oklahoma and Florida.

This profile was written by the staff of Boston.com based on material from The Boston Globe archives.