San Francisco police asked for the public’s help Monday in identifying a suspect in an attempted sexual assault in the Mission District.

Investigators said they believe the man depicted in a police sketch released Monday attacked a 31-year-old San Francisco woman as she was walking on 23rd Street near San Jose Avenue at about 2:40 a.m. Jan. 6.

The woman told officers that the man had stared at her as he approached. Then he lunged at her, grabbed her by the head and threw her to the pavement, according to police. He straddled her and slammed her head against the ground.

The woman fought back, freed herself and screamed for help. A resident yelled at the attacker to leave the woman alone, and the assailant fled east on 23rd toward Valencia Street, police said.