(AP) — A 6-year-old San Francisco Bay area boy has died after he was attacked by a relative’s dog.

Authorities say the attack occurred around 11:30 a.m. Monday at a grandparent’s home in Union City. The dog has been described as a pit bull or pit bull mix.

Union City Police Cmdr. Ben Horner says family members told investigators the boy was playing with the dog and may have attempted to climb on its back when he was attacked. The dog bit the boy on top of his head.

The boy has been identified as Nephi Selu. He died at Lucile Packard Children’s Hospital in Palo Alto.