Donald Killeen

In 1950, Donald's brother George was the first sibling to be murdered, found shot to death in the North End neighborhood. His murderers were never discovered. In 1971, Kenneth bit off the nose of Michael Dwyer, a rival Boston gang member and former brother-in-law of Boston Police Department Commissioner Francis Roche. Kenneth sent the severed nose to Boston City Hospital in a cab for reattachment. Kenneth's brother, Edward, was found dead from a gunshot wound in 1968, ruled a suicide. Kenneth became a father to a son in 1968.

He was murdered outside his home in Framingham, Massachusetts on May 13, 1972, while being lured away by an associate on his son Gregory's fourth birthday. He left the house under the pretense of fetching a newspaper, but actually went to retrieve his son's gift, a toy fire engine, from the trunk of his 1971 Chevrolet Nova. Donald retrieved a gun from under the driver's seat of his car, but before he could use it, a gunman opened the car door, pointed a machine gun at him, and fired fifteen rounds.

Killeen's murder remains unsolved.^[1] According to Patrick Nee, Paul McGonagle was the lead shooter in the killing.^[2] Kevin Weeks disputes this claim, stating that two other Mullen enforcers, "Jimmy Mantville and another fellow", were responsible for the hit.^[3] Conversely, a rumor suggests that Whitey Bulger may have killed Killeen to take over as gang boss.^[1][4]

The youngest brother, Kenny Killeen, was jogging past a parked car with four men in the City Point neighborhood of Boston. The men in the car were Whitey Bulger, Stephen Flemmi and John Martorano. He said that Bulger called him over to the car and said, "It's over. You're out of business. No further warnings"—a message to not try to take over his brothers' rackets or avenge their deaths.

• English, T. J. Paddy Whacked: The Untold Story of the Irish American Gangster. New York: HarperCollins, 2005. ISBN 0-06-059002-5
• Lehr, Dick; O'Neill, Gerard. Black Mass: The Irish Mob, the Boston FBI and a Devil's Deal. New York: Public Affairs, 2000. ISBN 1-891620-40-1
• Weeks, Kevin; Karas, Phyllis (2006). Brutal: The Untold Story of My Life Inside Whitey Bulger's Irish Mob. New York City: HarperCollins. ISBN 9780061122699.