Elmhurst police said the attack happened on the Illinois Prairie Path between York Street and the Pioneer Park area on Thursday night.
A man in his 30s allegedly battered a woman, who was running on the path, between 8:45 and 9 p.m.
Police released surveillance images of the suspect, who wore a red shirt, light colored cargo shorts, and a black cap.
The suspect left the scene on an electric scooter with a headlight on, riding west on Vallette Street from York Street.
Police asked anyone with information to call 911.