Ex-policeman says he deferred to Chauvin during George Floyd killing
Former Minneapolis police officer J. Alexander Keung arrives for a court hearing (AFP)

A former Minneapolis policeman has testified that he was a rookie still on probation on the day George Floyd was killed, and deferred to his senior officer Derek Chauvin, who was convicted of the murder of the 46-year-old African-American man.

J. Alexander Kueng, 28, is one of three former policemen facing federal charges of violating Floyd's civil rights in the May 2020 murder.

Chauvin, the white former Minneapolis officer who kneeled on the neck of a handcuffed Floyd for nearly 10 minutes until he passed out and died, is serving 22 years in prison for the murder.

Floyd's death was filmed by a bystander and sparked months of protests in the United States against racial injustice and police brutality.

Kueng, Tou Thao and Thomas Lane were the three other officers on the scene as Floyd was being taking into custody for allegedly using a fake $20 bill to buy a pack of cigarettes.

While Chauvin knelt on Floyd's neck, Kueng was on his back and Lane held his legs.

Thao kept bystanders, who were telling Chauvin to get off the visibly distressed Floyd, from getting any closer to the scene.

Kueng, who is Black, took the witness stand on Wednesday and Thursday and defended his actions.

He said Chauvin, an 18-year veteran of the force who had been one of his training officers, was "my senior officer, and I trusted his advice."

"It's always the senior officer who is the person who is control," said Kueng, who was working just his third shift on the street as a police officer.

"He had a lot of respect from other officers," Kueng said of Chauvin. "They would defer to him on what to do."

Kueng said he was partnered with Lane, who was also an inexperienced officer, that day.

"With us being new guys, we were paired together because no one wanted to work with us," he said.

Kueng said Chauvin intervened after he and Lane had failed to get a struggling Floyd under control.

He said it led him to believe "we were making a mistake or that he saw we were doing something incorrect."

'Deliberate indifference'

Thao, Kueng and Lane are charged with showing "deliberate indifference" to Floyd's medical needs.

Thao and Kueng are also accused of failing to intervene to stop Chauvin's use of "unreasonable force" against Floyd.

Lane does not face the second charge. Video of the arrest shows that on two occasions, Lane suggested Floyd be rolled over on his side.

Twelve jurors and six alternates are hearing the case against the three officers.

Thao, Kueng and Lane are to face Minnesota state charges in connection with Floyd's death in a trial that is scheduled to begin on June 13.

But in a sign of the importance of the case, federal prosecutors also charged the officers with violating Floyd's constitutional rights.

The federal trial is being held in a heavily guarded courtroom in Saint Paul, the sister city to Minneapolis.

All three men have pleaded not guilty.

Unlike Chauvin's state trial, the federal trial is not being televised.