California Highway Patrol officials on Friday said they were investigating an alleged altercation between an officer and a woman on the side of the 10 Freeway this week.
The incident was filmed Tuesday night by a passing driver and shows a woman walking toward a male officer on the side of the freeway near the La Brea Avenue exit.
It's unclear if the two were speaking to each other, but the officer throws the woman to the ground and hits her several times near the face before another man rushes in, according to footage in a KTLA-TV Channel 5 report.
The second man was a CHP officer in plain clothes, officials said.
At a Friday news conference, CHP officials said the woman had been walking in traffic and the officer was trying to restrain her. The woman was not injured and is undergoing psychiatric evaluation.
CHP officials would not identify the officer or woman but said they would conduct a full investigation.
"We will leave no stone unturned," said CHP Assistant Chief Chris O'Quinn, who said the video only captured a small part of the incident.