SAN FRANCISCO (CBS SF) — An Asian American female San Francisco police officer was taken to the hospital for treatment after she was assaulted in Chinatown — an attack captured on surveillance video.

The incident took place on Friday. A law enforcement source says the 911 caller who reported him as a disturbance that day had called the day prior, stating that the suspect said “I specialize in killing Asian people.”

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The video begins with the officer carrying a less lethal weapon ordering the suspect to face away from her and put his hands on his head. The suspect ignores her commands and is seen attacking the officer. He pushes her to the ground before he climbs on top of her. A bystander runs over and tries to yank the man off the officer.

Andy Min was one of a handful of people who rushed over to help. He said he was compelled to act for a couple of reasons.

“Just like a human being being attacked, and also it’s like a police officer, civil servant, and third it looked like there was a weapon,” Min said. “I couldn’t tell but I saw it hit the ground, so I didn’t know if it was in control or not, but just felt like something needed to happen.”

Min, who is seen in a blue shirt in the video, said he had been waiting for a table outside R & G Lounge.

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“There was a point where he had tackled her and I was like okay this isn’t going on – or this isn’t going right, and just kind of jumped in,” he added.

Officers arrived shortly thereafter. The suspect has been identified as 33-year-old Gerardo Contreras, who is homeless.

Max Leung is a Chinatown community organizer.

“I basically have seen him in Chinatown. He stays in the neighborhood in Portsmouth Square, and in the past it’s been obvious that he has mental health issues,” he said.

Contreras is facing charges of assault on a peace officer, false imprisonment and resisting arrest with a hate crime enhancement.

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The officer was taken to the hospital and suffered minor injuries.