The State College Police Department is investigating a report of a sexual assault that happened sometime between 2:30 and 4 a.m. Friday. Police are investigating the incident as a rape. A 21-year-old female Penn State student was sexually assaulted at an apartment on the 100 block of Keller Street by a male known to her after he walked her home from the Lion's Den, 118 S. Garner St., police said. The Mount Nittany Medical Center informed police of the incident at 5:04 a.m.