SANTA ANA (AP) — An 81-year-old man has pleaded not guilty to the beating death of his 94-year-old rehabilitation center roommate, an attack prosecutors say was triggered by the older man’s singing.

William Leo McDougall pleaded not guilty to murder during his arraignment Thursday in Orange County Superior Court.

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

Prosecutors told The Orange County Register that McDougall got mad because Nguyen was singing in Vietnamese so he took a metal rod from the closet and hit Nguyen repeatedly in the head.

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A nurse stopped the attack.

McDougall’s bail is $1 million. If convicted, he faces 25 years to life in prison.

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