A woman saw a man standing outside her bedroom window playing with himself at Pi Beta Phi sorority early Sunday, an Ann Arbor police report said.

The 21-year-old University of Michigan student looked out the third-floor window and saw the man at about 2:37 a.m. on a deck near the fire escape at the sorority on Tappan Avenue, the report said.

She screamed, hit the window, ran to her friend's room and called 911, according to the report. The woman did not get a look at the man's face, and only saw him from the chest area down, the report said.

He was described as white, 5 feet, 10 inches tall, of medium build and was wearing light blue jeans and a black fleece jacket, the report said.

Anyone with information can call police at (734) 794-6939.