Daughter Pleads Guilty In Mother's Murder At Assisted Living Home

A Los Angeles woman pleaded guilty Thursday to stabbing her 61-year-old mother to death at a senior living facility in Covina.

Athina Sumi Rivera was immediately sentenced to 16 years to life in state prison after pleading guilty to second-degree murder and admitting that she used a knife during the attack on her mother, Margaret Yamaguchi.

Rivera, 44, was spending the night in her mother's room at the facility in the 800 block of West San Bernardino Road when she got up in the middle of the night and stabbed her several times on Sept. 7, 2015, according to Deputy District Attorney Lauren Guber.

An emergency call was made from the room during the attack, and employees of the facility found the victim bleeding heavily. Yamaguchi was pronounced dead at the scene.

Rivera was arrested about a half-hour later and has remained behind bars since then.

Photo, Covina Police Department