LAGUNA WOODS, Calif. (AP) — An 83-year-old man has been convicted in the beating death of his 94-year-old roommate at a California health care facility, an attack prosecutors say was triggered by the older man's singing.

A district attorney's statement says William Leo McDougall was convicted Friday in Orange County Superior Court.

McDougall and Manh Van Nguyen were both recovering from hip surgery at Palm Terrace Healthcare Center in Laguna Woods on Oct. 1, 2010.

Prosecutors say McDougall got mad because Nguyen was singing in Vietnamese, so he took a wooden rod from the closet and hit his roommate repeatedly in the head.

A nurse stopped the attack, but Nguyen later died due to blunt force trauma.

McDougall will be sentenced Oct. 26.