SAN DIEGO -- Authorities asked the public Friday for help in identifying a man who grabbed and fondled an Ocean Beach woman on a roadside a few blocks from her home last weekend.

The 27-year-old victim was walking in the 2000 block of Cable Street shortly before 2:30 a.m. Sunday when the assailant strolled past her, then paused and waited for her to catch up to him, according to police.

As the woman tried to get around the man, he touched her buttocks. She protested and tried to push his hand away, at which point he grabbed her around the waist from behind and thrust his pelvis against her four or five times, police said.

The woman was able to escape after dousing the attacker in the face with pepper spray.

The victim described the assailant as a roughly 5-foot-9-inch tall black man in his mid-20s or early 30s, wearing light-colored blue jeans with a design of some kind on the rear pockets and a light-green, button-down shirt with long sleeves.

San Diego County Crime Stoppers is offering a reward of up to $1,000 for information that leads to an arrest in the case. Tipsters are asked to contact the nonprofit agency at 888-580-8477. Callers may remain anonymous.