He drove her into the downtown area and pulled into Public Parking Structure 2 at 1235 2nd St. Detectives said he then pulled out a handgun and sexually assaulted the woman.
The suspect drove out of the parking structure, then sped away westbound on Wilshire Boulevard.
The suspect is described as a Hispanic male, about 40 years old, 5-foot-5, with a heavy build. He's believed to be driving a sport utility vehicle, possibly a late model gray Saturn Vue or a similar vehicle with a roof rack.
Anyone with information on the case is urged to call Santa Monica Police at (310) 458-8495.