An Altoona man has been arrested after he allegedly assaulted a teenager several times last month. Arraigned yesterday was 46-year-old William Koch. He has been charged with a felony count of rape of an unconscious victim, rape by forcible compulsion, and other related counts. Altoona Police report their investigation began after the victim told a friend about the assaults, and the friend contacted authorities. Reportedly, Koch had sex with the victim while she was sleeping. Koch has been placed in the Blair County Prison, bail having been set at $50,000. A preliminary hearing is scheduled for April 23rd.