A 4-year-old boy was mauled to death by a family dog as he and his two brothers played in a bedroom of their apartment in Brooklyn, the authorities said on Saturday.

The boy, Jayelin Graham, suffered “multiple bite wounds” on his head, his neck and other parts of his body, said a law enforcement official.

The attack occurred about 9:20 p.m. Friday in the family’s first-floor apartment, at 2169 Pacific Street, in Brownsville, the police said. The Brooklyn district attorney’s office and the city’s health department were investigating.

Detectives and a spokesman for Animal Care and Control of New York City could not say what caused the dog, a male Cane Corso who is 7 or 8 years old, to attack.