GRAY — A 15-year-old boy has been charged with sexually assaulting an 8-year-old female family member who has autism and fetal alcohol syndrome, the Cumberland County Sheriff’s Office announced Friday.

The boy was living at the victim’s home in Gray when the assault happened at 6 p.m. Thursday, according to a news release.

The boy has been charged with gross sexual assault and unlawful sexual contact. He is being held at the Long Creek Youth Development Center in South Portland pending further investigation and court proceedings.

The boy recently was charged with a single count of indecent conduct in an unrelated incident in Augusta, according to the news release.