PULLMAN, Wash. -

Pullman police are investigating reports of sexual assault at a Washington State University fraternity.

Police were called to the Pullman Regional Hospital around 6:30 p.m. Friday where an 18-year-old female WSU student was being treated. The victim reported that she was provided alcohol and was sexually assaulted at the Delta Upsilon fraternity at 815 NE Ruby St.

Officers were called to the hospital again around 2 Saturday morning. A 17-year-old female WSU student reported that she was given alcohol at the same fraternity earlier in the evening and later became ill.

Investigators served a search warrant at Delta Upsilon Saturday afternoon and collected evidence. They interviewed a possible suspect in the sexual assault investigation. The suspect was not arrested pending additional investigation. The Office of Student Conduct at Washington State University was notified of the investigations.