A 5-year-old boy died after being attacked by his family’s pit bull at an Oro Grande home Monday afternoon, San Bernardino County Sheriff’s Department officials said.

The child was home with an adult family member when the dog attacked him shortly before 3 p.m. in the 15100 block of Portland Street, Sgt. Jeff Allison told KTLA.

The family member called 911 and said that the dog was attacking the child and would not let go, according to the Sheriff’s Department.

The boy sustained significant injuries during the attack and had already died before law enforcement arrived.

San Bernardino County Animal Control took custody of the dog, according to the Sheriff’s Department. It’s unclear what prompted the attack.

Investigators found that the dog started attacking the child when the adult stepped out of the room.

The child’s parents were notified and investigators responded to the home to interview family members, Allison said.

Video from the scene showed firefighters, paramedics and deputies responding to the home, which was cordoned off with police tape.

A dark brown pit bull could be seen being led into a county animal control truck.

The incident remains under investigation and no further details were immediately available.

Anyone with information can call Victor Valley Sheriff’s Station Detective J. Collins at 760-552-6800. Those who wish to remain anonymous can call the WeTip hotline at 1-800-78-CRIME.

KTLA’s Matt Phillips contributed to this report.