Detectives said this person approached a woman at the Clark and Lake platform in the Loop about 5:50 a.m. Sunday morning and ripped her purse off her shoulder.
RELATED: Uptown robberies: Chicago police investigating after 2 women robbed at gunpoint on North Side
He's described as 18 to 25 years old; 5-feet, 10-inches to 6-feet tall; having black hair; and wearing a black T-shirt, dark jeans and dark shoes with white soles.
Anyone with information on the incident is asked to call the Bureau of Detectives - Mass Transit at (312)-745-4443. Anonymous tips can be submitted to CPDTIP.com.