Police are warning residents of a criminal sexual assault Sunday night in South Chicago.

A woman was walking down the street when she noticed a male she didn’t know following her about 10:30 p.m. in the 8200 block of S. Escanaba Avenue, according to Chicago Police.

When she tried to run away, the male grabbed her and forced her into an alley where he sexually assaulted her, police said.

A detailed description of the suspect was not available.

Anyone with information was asked to contact Area South detectives (312) 747-8271.