Martha T. Moore

USA TODAY

A motorist's video of a California highway patrolman repeatedly punching a woman has sparked local outrage and a police investigation into the officer's actions.

In the incident, which happened in Los Angeles on Tuesday at an on-ramp to the Santa Monica Freeway, a California Highway Patrol officer appears to be attempting to stop a woman walking on the shoulder of the road and cutting across traffic. The video shows the officer pinning the woman on the ground and hitting her in the face and head until a second man — later identified by police as an off-duty plainclothes officer — arrives and helps the first officer handcuff the woman.

The woman ignored the officer's command to stop and became "physically combative," according to a CHP statement Saturday.

"The officer (was) forced to place the pedestrian under arrest in fear of the pedestrian and the officer's safety. A physical altercation ensued,'' the police statement said.

The officer, who has not been identified, has been placed on administrative leave. An investigation is underway, CHP Assistant Chief Chris O'Quinn said at a news conference Friday. "We're looking at every possibility, every fact, every circumstance that could have contributed to this situation, and we're going to try to come to a just conclusion.''

Police said the woman, who was walking along the roadside barefoot, was not injured. She was taken to Los Angeles County-USC Medical Center and released the next day, hospital spokeswoman Rosa Sava said.

The video, taken by Los Angeles resident David Diaz, was posted on YouTube and sent to local news outlets. Diaz told the Associated Press that he arrived as the woman was walking on the freeway on-ramp. He said she turned around only after the officer shouted something to her.

"He agitated the situation more than helped it," Diaz said of the patrol officer.

The video caught the attention of local civil rights leaders, who expressed shock and outrage at their own news conference Friday.

"What we saw in that video was a civil rights abuse, a civil rights violation,'' said writer Earl Ofari Hutchinson, founder of the Los Angeles Urban Policy Roundtable.

"Speaking for the women of this community, we are angry, we are upset," Lita Herron of the Youth Advocacy Coalition said.

O'Quinn said that the CHP would answer community concerns and that an investigative team already has been assembled and has begun its work.

"We are known as an agency that really polices itself," O'Quinn said.

Hutchinson, speaking at the local leaders' news conference, agreed.

"Over the years, CHP has had a very good track record in terms of community relations," Hutchinson said. "That's why this was so shocking."

O'Quinn said he couldn't say what prompted the officer to act as he did. But he noted patrol officers have a better sense of the danger of highway traffic than someone "who is not accustomed to the speed and conditions," especially outside of a car.

"The most dangerous thing that we face is traffic," O'Quinn said.

Contributing: The Associated Press