Milton J. Valencia
Boston Globe 
Friday, Sept 25th, 2009
A Boston officer who was at the center of the notorious, near-deadly police beating of another patrolman nearly 15 years ago faces new allegations of police abuse, in a federal lawsuit that alleges the department allowed him to work despite his past “overly aggressive’’ behavior.
Officer David Williams and his partner, Diep Nguyen, were named in the lawsuit filed yesterday in federal court in Boston seeking unspecified damages in the March beating of Michael O’Brien, 29, of Boston.
O’Brien asserts he was attacked by Nguyen and Williams when he tried to record them with his cellphone after a minor car accident. Nguyen allegedly grabbed the phone, and O’Brien tackled him, choked him from behind, nearly strangling him, and hit him in the head.
The lawsuit says other, unidentified officers arrived but did nothing to prevent the attack.