The incident happened at about 7:45 p.m. on May 23 in the 8100-block of South Pulaski Road.
Police said a woman was leaving a store when the suspect approached and sexually abused her.
The suspect is described by police as an African-American man between 18 to 19 years old. He's about 5'7 to 5'9 with a short, black fade hairstyle. He was wearing a gray Chicago Blackhawks T-shirt, black sweatpants, black socks and slide-on sandals.
Anyone with information is asked to contact Area Central Detectives at (312) 745-8380.