The California Highway Patrol will conduct a thorough investigation after a video emerged of one of its officers repeatedly punching a pinned-down woman on the side of a Los Angeles freeway.

The woman had been walking on Interstate 10 west of downtown Los Angeles, putting herself and people in traffic in danger. The police officer was trying to restrain her, said CHP Assistant Chief Chris O’Quinn.

O’Quinn said the woman began walking off the freeway, but returned when the confrontation occurred.

The video shows the woman struggling and trying to sit up while the police officer punches her in the face and head until an off-duty law enforcement officer appears and helps him handcuff her.

Passing Driver David Diaz recorded the Tuesday incident and provided it to media outlets including The Associated Press. He said the woman turned around only after the officer shouted something to her.

“He agitated the situation more than helped it,” said Diaz, who started filming soon after the confrontation began.

The officer is on administrative leave while the patrol investigates.

The local civil rights leaders expressed shock and outrage at their own news conference. “Speaking for the women of this community, we are angry, we are upset,” said Lita Herron of the Youth Advocacy Coalition.

O’Quinn said the CHP would answer community concerns and an investigative team already has been assembled and has begun its work. He stated that the incident report listed no injuries for the woman, who would not give her name. She is undergoing psychiatric evaluation, he said.

Police brutality is a major cause of concern in the U.S., and this incident is not the first to be caught on film. Some police forces are more extreme than others. According to the Center for Research on Globalization, “500 innocent Americans are murdered by police every year (USDOJ).”