Four days after a random attack on a San Francisco pedestrian, police have released video of the brutal beating in hopes that it might help them track down the suspect.

According to the San Francisco Police Department, the female victim was taking a walk at Lafayette Park at around 7:45 p.m. on Saturday, August 20 when she was first approached by the suspect. She didn't speak to him, but he approached her again as she walked on the 2000 block of Washington Street, which is between Octavia and Gough Streets at the border of the park.

As you can see in the video below — which, I will warn you, is extremely violent and upsetting, so give it a think before you hit play — this time the suspect ran up to the woman, tapped her on the shoulder, then punched her repeatedly until she fell to the ground. Once she was on the ground he continued to beat her, pinning her to the pavement with his knee. It's decidedly vile.

Following the attack, police say that the man fled east on Washington, then south on Gough, but hasn't been seen since. SFPD posted the surveillance video showing the attack Wednesday evening, in hopes that someone like you might recognize the suspect and help them identify him.

Police emphasize that the woman did not know her attacker, nor did she speak with him prior to the assault.

"I believe he asked her to say, 'Say you're sorry,' something along those lines, and she had absolutely no idea what he was talking about because she did not know him," police spokeswoman Giselle Talkoff told NBC Bay Area.

"She was merely on a walk in that area and saw him run up in the corner of her eye. He said some words and then just started attacking her," Talkoff told ABC 7.

Police say that the victim suffered cuts to the face, and had her nose "broken in several places." As of Wednesday, she remained in the hospital, recovering from her injuries.

Talkoff says that the victim "pretty much did what she could," during the unprovoked assault. "It happened all of a sudden," Talkoff says, "he was larger than her, and she was knocked to the ground. So she had her arms up trying to defend herself, but there was nothing else in a sudden attack like that she could have done."

“It kind of happened really quickly,” Talkoff told the Chron. “She was merely out for a walk and a stranger came up and just attacked.”

Police describe the suspect as "a white male, possibly homeless, 40 - 50 years old, brown hair, average build, wearing a dark green zip-up sweater/shirt and jeans." Do you recognize this guy, or know anything about this case? If so, police ask that you call SFPD's Anonymous Tip Line at 415-575-4444 or text a tip to TIP411 with SFPD at the beginning of the message.