CHICAGO (CBS) — Bernard Kersh, a schizophrenic man who was body-slammed by a Chicago police officer on Thanksgiving Day last year, is suing the city, accusing Officer Jerald Williams of using excessive force.

Williams was caught on cell phone video as he lifted Kersh off his feet and slammed him into the pavement on Nov. 28, 2019, at the corner of 79th Street and Cottage Grove Avenue.

The video shows Kersh’s head slamming against the curb, and he doesn’t move for the rest of the 40-second video.

“He picked me off my feet and slammed me head first into the concrete,” Kersh said in an interview with CBS 2 weeks later. “I could have been killed.”

CBS 2 Investigators have exposed that Officer Williams is an MMA fighter.

YouTube videos show him using similar maneuvers in the ring.

CBS 2 showed all of the videos to Dr. Geoffrey Alpert, a criminal justice expert who has testified on both sides of police misconduct cases.

“That might be a good move in the ring – it’s certainly not a good move on the street,” Alpert said. “It’s not necessary to throw him to the ground. It’s clearly an excessive take down, and it’s not justified.”

Kersh, 29, has filed a lawsuit in Cook County Circuit Court against the city and Williams, accusing the officer of willful and wanton conduct.

In the lawsuit, Kersh’s attorneys claim he suffered “severe bodily injuries, including to his head, neck, shoulder, and is in danger of going blind in his left eye.”

Kersh’s family’s attorney also has said Kersh suffers from mental health issues, including schizophrenia.

Williams and a second officer have been stripped of their police powers, pending an investigation by the Civilian Office of Police Accountability.

Police said officers stopped Kersh that night to give him a ticket when they saw him drinking alcohol in plain view at a bus stop. That’s when they said he resisted arrest, and spat at and licked an officer’s face.

The Police Department called the incident an “emergency takedown,” but Kersh’s defense attorney has called it “a brutal and vicious attack.”

“Mr. Kersh was not armed, engaging in any threatening behavior, or otherwise resisting,” his attorneys wrote in their lawsuit.

The lawsuit claims Williams’ partner, identified only as “Officer Kerr,” walked away after Williams had forced Kersh against a white police SUV to check if Kersh had any outstanding warrants, and claim “Kerr’s actions confirm that [Kersh] was not resisting, threatening, or otherwise placing Officer Williams or any third party in any physical danger.”

The lawsuit also claims, even after slamming Kersh to the ground and knocking him unconscious, Williams performed “a forearm strike to his head.”

“Officer Williams, as an agent, employee, and sworn officer of the City of Chicago, committed willful and wanton conduct by exhibiting actual or deliberate intent to harm, or through a course of action which showed an utter indifference to or conscious disregard for the safety of another, in one or more of the following respects,” the lawsuit states.

“His attack on Bernard could have killed him. Thank God Bernard is going to be OK, we hope. But it’s a pattern and practice with the Chicago Police Department and the behavior of the officers. We are demanding that Lori Lightfoot follows through and that there is an investigation into this officer, and someone is held accountable,” civil rights attorney Andrew M. Stroth said days after the incident.

In that incident, Kersh was charged with one felony count of aggravated battery, one misdemeanor account of resisting police and one misdemeanor count of simple assault. He was also cited for drinking alcohol in public.

Surveillance camera footage showed police dragging Kersh into a cruiser, leading with his head. On police body camera video, one officer could be heard commenting in real time that it could have been handled better.

“Did an amazing job. Sarcasm,” the officer said.

“That demonstrates well, that was excessive, that shouldn’t happen. But did any officer report it? No,” said Alexa Van Brunt, legal director of the MacArthur Justice Center at Northwestern University.

In the security footage, Kersh is seen motioning toward Williams right before the takedown, but it’s unclear in the video if he licked or spit at him. Williams can be seen wiping his face after slamming Kersh.

Kersh said when he hit the curb, he “blanked out” and was knocked unconscious.

“Everything went black,” he said.

The security video first shows a white police SUV pull up to a bus stop. Williams gets out of the vehicle, goes into the bus shelter and grabs Kersh, who is drinking liquor. Williams positions Kersh with his chest up against the vehicle.

“So you can see, I’m not being resistant or anything,” Kersh said, while watching the video. “I’m in compliance.”

Kersh appears to cooperate for most of the video and at one point is seen talking on his cell phone with his left hand. He said he was talking to his mother, Keshia Johnson, to tell her what was happening.

Several seconds before the body slam, Williams seems to be pressing his body up against Kersh, who then turns his face toward the officer. Williams then wraps his arms around him and body slams him.

“The subject is apparently being cooperative,” Alpert said. He noted Williams’ partner is seen in the video walking away to go around the car.

“So he’s not seeing any threat, not seeing any resistance,” Alpert said. “It’s just kind of a routine situation that turns very ugly, very quickly.”

Kersh was released from Cook County Jail about a week after his arrest, after Rev. Jesse Jackson posted bail.

He has denied spitting or licking any officer the night of his arrest.

“I didn’t spit at no officer,” Kersh told CBS 2 Investigator Dave Savini. “I didn’t lick no officer’s face.”

Last month new trouble came for Kersh, who was accused of shoplifting from a South Loop store and shoving a female security who tried to stop him.

Police said, around 10:05 a.m. on Jan. 23, Kersh walked into a retail store in the 1200 block of South Wabash Avenue, took some merchandise, and tried to leave without paying.

A 22-year-old woman working as a security guard tried to stop Kersh from leaving, but Kersh shoved her in the chest and fled, police alleged. The security guard declined medical treatment.

Officers toured the area and located Kersh, police said. He was arrested at 10:37 a.m., police said. He was charged with aggravated battery to a merchant and felony retail theft.

He is being held at the Cook County Jail on $100,000 bail on the most recent charges.