Police say a 15-year-old boy allegedly raped a girl under the age of 7 numerous times over a several month span, including on Saturday when he was arrested.

Around 1:15 p.m. Saturday, the father of the victim said the 15-year-old came over after an argument with his mother, according to the police report.

The boy then went up stairs to visit the father’s two young girls, one age 6 and one age 4. About an hour later, the father of the girls went to check on them and “witnessed a sexual assault.” He called the police.

Lt. Scott Reeve said the boy has allegedly been sexually assaulting the 6-year-old girl for about six months. The 15-year-old, who turns 15 today, was charged with one count of rape.

The boy was arraigned Monday before Butler County Juvenile Court Judge Ron Craft. He was remanded to the Butler County Juvenile Detention Center. A pretrial is set for 2 p.m. on Aug. 7.