A 15-year-old boy is in custody, accused of committing sex crimes against a child. Details are scarce due to the ages of the suspect and the girl, but about 8 a.m. Wednesday, deputies were called to a home in the 6700 block of Elk Trail in Twentynine Palms where the alleged crime occurred. After an investigation, a detective in the Crimes Against Children unit arrested the 15-year-old boy, who is accused of sexually assaulting a 9-year-old girl. The boy was taken to Juvenile Hall.