Known as "The Irish Godfather" of Boston, Bulger has been on the FBI's Top Ten Most Wanted posters for years and was an inspiration for the 2006 movie The Departed.
Along with Stephen "The Rifleman" Flemmi, he led the violent Winter Hill Gang, a largely Irish mob that ran loan-sharking, gambling and drug rackets in the Boston area. U.S. Attorney Donald K. Stern said in 2000 that the two were "responsible for a reign of intimidation and murder that spanned 25 years."
In the 1970s, Bulger became a top-secret FBI informant in Boston but later corrupted his handlers.
The agents "tipped him off to investigations by other police agencies and they also tipped him off to other people who were informing against him so that he could and did murder them," said David Boeri, a reporter from member station WBUR in Boston who has followed the Bulger case for more than two decades.
NPR
I'm guessing a good number of people here won't be familiar with this story but its pretty fascinating and terrifying. In the late 70s 'Whitey' became an FBI informant handled by agent John Connelly, a childhood friend from South Boston as well.
Soon information began flowing the other way and Bulger used his FBI status to take down large portions of the Italian mafia in New England as well as hunt down would-be informants.
Since being on the lam since 1995 Bulger has frequently been near the top of the FBI's most wanted list (don't quote me on this, but I believe bin Laden was the only one with a higher reward).
As a Masshole expat all I can say is, and I choose these words carefully, that Bulger is human garbage and I'm glad he will not die a free man.