Evanston police are investigating a report of a sexual assault late Monday in the 700 block of Central Street.
Police Cmdr. Jay Parrott says police learned about the incident from a third party. He says the victim is a 23-year-old Chicago woman.
Parrott says the incident happened between 10 p.m. and midnight and that no one is in police custody at this time.
Update: 6:30 p.m.: Northwestern University police say the victim is not affiliated with the university. They say the woman was walking a dog in an alley on the block when she was confronted by a man who displayed a gun and sexually assaulted her.
The victim was taken to a hospital where she was treated and released.
NU police say the suspect is a 30- to 50-year-old white male, 5-feet-10-inches to 6-feet tall, wearing a dark knit cap, dark coat and dark pants.