SAN FRANCISCO (AP) — A San Francisco man has been charged with killing a 7-month-old boy who was in his care. Joseph Williams was charged Monday with murder and assault on a child causing death.

The San Francisco district attorney's office says Williams was babysitting the boy on April 20 and later that day brought the child to a hospital.

The baby died of traumatic head injuries caused by blunt force.

Authorities say the child wasn't related to Williams. They didn't provide details of what might have caused the injuries