A police training expert testified Saturday in a defense witness on trial of three former Memphis police officers charged with fatal tire Nichols who admitted kicking Nichols in the head was unnecessary and excessive.

Don Cameron took the stance on the sixth day of the trials of Tadarrius Bean, Demetrius Haley and Justin Smith, who pleaded not guilty to state charges, including second-degree murder. They are already facing the prospect of a year in prison after they were found guilty of federal charges last year.

Nichols is a 29-year-old black man at a January 2023 traffic stop where he was kicked out of the car, pepper sprayed and hit with a stun gun. Five other black officers caught up with him, slammed with batons, kicked and hit Nichols, trying to handcuff him as he called his mother near his home.

The footage of the beating captured by the police camera also shows police talking, talking and laughing as Nichols struggles. His death led to nationwide protests, calls for police reform in the United States, and rigorous scrutiny of Memphis in most black cities.

Officials were charged with second-degree murder, serious assault, aggravated kidnapping, formal misconduct and official oppression. Prosecutors argued that officers used too much power while trying to handcuffed Nicole people. The officers also have the responsibility to intervene and stop the beatings, prosecutors said, and told medical staff that Nichols had hit the head, but they did not do so.

Memphis officials Desmond Mills Jr. and Emmitt Martin are also charged. They have agreed to plead guilty to state charges, rather than regular trials. They also pleaded guilty in federal court, with all five officers under trial.

Defense attorneys tried to evade allegations that officers used unnecessary troops to subdue Nichols. They argued that Nichols actively resisted arrest by running away and failed to hand over his hands to the officer so he could put his handcuffs. They also argued that their use of force complies with police department policies.

Cameron was taken to the stands by a defense attorney, and Haley was at the traffic stop, and when Martin kicked Nichols and arrived at the beaten spot when he kicked Nichols by Smith and Bean.

Cameron said Nichols had not been handcuffed yet and Hayley kicked Nichol once with the right force. The veteran police coach said Hayley kicked Nichols to facilitate other officers to put Nichol's handcuffs.

However, under cross-examination by Prosecutor Paul Hagerman, Cameron acknowledged that Martin’s fists and kicks on Nichols’ heads were unnecessary, excessive, and an example of fatal force. Cameron said officers who saw these head blows had the responsibility to intervene and stop the beating.

The prosecutor also asked Cameron about Hayley's comments on "beating that man" as he got out of the car and approached Nichols. Cameron said he believed Hayley made a comment so that Nichols would be put on after obeying Nichols’ repeated neglect of picky orders.

Mills hit Nichols three times with the police department on Tuesday, regretting that he failed to stop the assault, which resulted in Nichols' death from blunt-arm trauma three days later. Dr. Marco Ross, a medical examiner who performed the autopsy testified Wednesday that Nichols shed tears and bleeding in his brain.

The trial comes months after the U.S. Department of Justice said in December, a 17-month investigation found that the Memphis Police Department used too much force and discriminated against black people.