MILLERSVILLE, Pa. (AP) -- Police are investigating a reported rape at an off-campus party at Millersville University. Millersville Borough police Chief John Rochat said a student went to a party with friends Saturday night and realized after leaving that she had left her keys behind. Rochat said the 19-year-old woman returned to the party by herself and was jumped and sexually assaulted. The woman said she did not know her assailant and had not interacted with him at the party. She reported the incident to police on Sunday and was taken to the hospital to be checked. Police are conducting interviews but said because it's finals week at the central Pennsylvania university, some undergraduates have left for the semester or will be moving out in the next few days.