Authorities say an 81-year-old man has been charged with the murder of his 94-year-old roommate at a Southern California rehabilitation center where the two were recovering from hip surgeries.

Prosecutors said Monday that William McDougall became angry with 94-year-old Manh Van Nguyen, who was singing in their room in Vietnamese at the Palm Terrace Health Care Center in Laguna Woods.

McDougall is accused of taking a metal rod from the closet and hitting Nguyen multiple times on the head. Nguyen died at a hospital.

McDougall faces 25 years to life in state prison if convicted of the Oct. 1 attack.

He is scheduled to be arraigned Tuesday in Santa Ana.