California Highway Patrol officer Daniel Andrew faces "potentially serious charges" for throwing a woman to the ground, straddling her and repeatedly punching her in the head on the side of the road.
Marlene Pinnock, 51, was walking on the side of the 10 Freeway at the La Brea Avenue exit in July before being stopped by Andrew.
The officer claimed that he was attempting to protect Pinnock, who reportedly walked into the motorway lanes.
Pinnock was arrested and put on a 72-hour mental health hold.
Andrew, who was put on a desk assignment after the incident, was removed from duty and put on paid administrative leave
The incident that was filmed by passing motorist David Diaz and posted to YouTube, causing widespread outrage.
Pinnock has been diagnosed with bipolar disorder and was off her medication for two to three months before the altercation, said Pinnock’s attorney Caree Harper.
In an interview with the Associated Press, Pinnock said she believed the officer was trying to kill her.
"He grabbed me, he threw me down, he started beating me. I felt like he was trying to kill me, beat me to death," she said.
California Highway Patrol said in statement: "The CHP understands the public’s interest in this case, and it is our desire to be as transparent as possible while adhering to the laws and due process that govern any investigation.
"We value the public’s trust and appreciate the community’s patience as we complete this important process."