Authorities released a composite sketch of a man accused of attacking a woman on a bicycle around 11:20 p.m. Thursday near Willows Avenue and Napa Creek Drive.
The man allegedly tackled the woman from behind and tried to sexually assault her, but she fought back and got away.
The suspect was described as a man in his early 20s with a muscular build and short dark hair. He may have an injury to the right side of his face.
Anyone with information was asked to call the Riverside County Sheriff's Department at (951) 696-3000.