Police are asking riders on the Orange Line to be on alert after a woman was touched inappropriately.
It happened at 11 a.m. yesterday at the Orange Line station on 50 E. Roosevelt.
The woman was riding the escalator on the train platform when a man approached her from behind and placed his hand on her leg.
He got away, but was caught on surveillance cameras.
The suspect is described as an Asian male between 20 and 30 years old..
He was wearing glasses, jeans and carrying a backpack.
Anyone with information should call Chicago police.