The assault happened on Sunday sometime between 2:45 a.m. and 3:30 a.m. on the 1200 block of Huntington Drive near the 210 Freeway.
The investigators released surveillance images from the incident.
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Officials describe the suspect as a Black male adult, approximately 6 feet tall, 200 pounds, with black hair and brown eyes.
No other details have been released.
The Los Angeles County Sheriff's Department has asked anyone within a half-mile vicinity to check any security cameras for video footage of any suspicious activity around the time of the assault.
Anyone with information is asked to contact the sheriff's Special Victims Bureau toll free tip line at (877) 710-5273. Those wishing to remain anonymous may dial Crime Stoppers at (800) 222-8477.