Joseph Weiser, 19, of Bergman, was arrested on Monday.
Sheriff Danny Hickman says the Boone County Sheriff's Office (BCSO) found out about the alleged attack of the girl after she was taken to the Grandma's House Child Advocacy Center in Harrison for an interview. The information she gave authorities led to Weiser's arrest.
When deputies interviewed Weiser, the BCSO says he confessed to raping the girl and fondling the boy.
Weiser faces four counts of rape and sexual assault.