William S. O'Sullivan, Date of Birth, Date of Death
TweetWilliam S. O'Sullivan
American criminal and mobster
Date of Birth: 
About William S. O'Sullivan
- William S.
- O'Sullivan (January 31, 1928 – March 28, 1971) was an Irish-American loanshark and longtime enforcer for Donald Killeen, the head of the Irish mob in South Boston, Massachusetts.
- O'Sullivan also acted as a mentor to a young James J.
- Bulger, who grew up to become the leader of Boston's Winter Hill Gang.
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