A 4-year-old Brooklyn boy was mauled to death by his family dog Friday night, police said Saturday. The boy, Jayelin Graham, suffered “multiple bite wounds” on his head, neck, and throughout his body, police said. Jayelin’s mother, Saquina Jubeark, said Jayelin and his brothers, ages 2 and 5, were playing in their bedroom while she retrieved some keys from her 10-month-old daughter’s stroller. Police said at some point she realized the boys’ room had gone very quiet, and when she went in to investigate, she found the dog standing over Jayelin and biting him while the other kids were hiding under the bed. A neighbor, hearing the screams, called 911. Officers from the Emergency Services Unit tranquilized the dog, a Cane Corso breed, and took a second dog, a Husky, into custody.