Police in Northern California say officers shot and killed a 60-year-old man after he attacked his elderly parents.

San Francisco news station KPIX-TV reports t hat the couple, ages 85 and 90, called Concord police Sunday to say their son was acting “erratically” and was possibly under the influence of drugs and alcohol.

Police Cpl. David Petty says they told dispatchers their son was armed with a knife and a plastic gun.

As officers approached the man, he went back into his parents’ home. Police then saw the father walk outside with serious injuries.

Petty says officers went inside the home and found the attacker “straddling” his mother while holding a knife and fired their weapons at him.

The parents were brought to a hospital to be treated for serious injuries.