Mr. and Mrs. William O’Sullivan of Savin Hill. O’Sullivan, who had no record, was a tough loanshark who operated out of the Combat Zone. In 1970, Whitey’s boss, Donnie Killeen, realized he was outgunned in the gang war that was ongoing in Southie, and so he brought on O’Sullivan, a friend of Stevie Flemmi and Frank Salemme, both of whom had gone on the lam a year earlier.
The Killeens and the McGonagles had a few run-ins, which left one of the McGonagles noseless, and another (the brother of future police commissioner Francis “Mickey” Roache) paralyzed, the McGonagles decided to take out one of Donnie’s hired hands – either Whitey or O’Sullivan.
Whitey took precautions, O’Sullivan didn’t.
 

 Read the newspaper account of O’Sullivan’s murder.

At the time, on direct orders from FBI director J. Edgar Hoover, agent Dennis Condon was trying to recruit Whitey as an informant. Although no formal deal would be struck until 1975, Whitey was telling Condon plenty. Read his story of the gang war that claimed the life of William O’Sullivan.
 

In June 1972, Whitey ended the gang war, by killing his boss, Donnie Killeen, after obtaining the blessing of Howie Winter of Somerville, the boss of Boston’s pre-eminent non-Mafia mob, the Winter Hill Gang.