Woman brutally attacked on sidewalk in SF’s Pacific Heights

A woman in her 50s suffered a broken nose and will require surgery after a stranger stopped her on a San Francisco street and punched her repeatedly in face and head for no apparent reason, authorities said Wednesday as they released security video of the unprovoked assault.

The attacker remained on the loose Wednesday and police officials are asking for the public’s help in catching him.

“It kind of happened really quickly,” said Officer Giselle Talkoff, a spokeswoman for the San Francisco Police Department. “She was merely out for a walk and a stranger came up and just attacked.”

San Francisco Police are hunting for a man who brutally beat a woman police say he randomly targeted on a sidewalk near Lafayette Park in the city's Pacific Heights neighborhood on Saturday, Aug. 20, 2016. San Francisco Police are hunting for a man who brutally beat a woman police say he randomly targeted on a sidewalk near Lafayette Park in the city's Pacific Heights neighborhood on Saturday, Aug. 20, 2016. Photo: San Francisco Police Department / / Photo: San Francisco Police Department / / Image 1 of / 3 Caption Close Woman brutally attacked on sidewalk in SF’s Pacific Heights 1 / 3 Back to Gallery

The victim of the beating had left Lafayette Park in the Pacific Heights neighborhood about 7:45 p.m. Saturday when a man in his 40s or 50s approached her from behind on the 2000 block of Washington Street.

Surveillance video released by the San Francisco Police Department showed the woman walking down the sidewalk and turning back to look at the man jogging toward her and wearing a dark hoodie. Without warning, he grabbed her by the arm and punched her in the face. He continued hitting her numerous times as he dragged her to the ground. The attack went on until the woman was rendered motionless on the sidewalk.

Her nose was broken in several places and she will need surgery, police said.

The victim, whose name was not released, did not speak to her attacker, but the assailant, a complete stranger, might have asked her to apologize for something before the attack, said Talkoff. It was possible the man was under the influence of drugs or alcohol, Talkoff said.

The woman’s attacker ran east on Washington Street and vanished after turning south on Gough Street.

The victim was taken to a hospital and treated for non-life threatening injuries.

Anyone who recognizes the suspect can call San Francisco Police at (415) 575-4444.

Jenna Lyons is a San Francisco Chronicle staff writer. Email: jlyons@sfchronicle.com Twitter: @JennaJourno