A use-of-force expert testified Monday against three former Minneapolis police officers who are charged with violating George Floyd’s civil rights, saying their conduct was “inconsistent” with generally accepted policing practices.

Tim Longo, the police chief at the University of Virginia at Charlottesville, said he reviewed videos, Minneapolis Police Department policies, training materials and other items to evaluate the conduct of J. Alexander Kueng, Thomas Lane and Tou Thao.

The officers are charged with violating Floyd’s constitutional rights while acting under government authority. All three are accused of depriving Floyd, a 46-year-old Black man, of medical care while he was handcuffed, facedown as Officer Derek Chauvin pressed his knee onto Floyd’s neck for 9 1/2 minutes. Kueng, who is Black, knelt on Floyd’s back; Lane, who is white, held down his legs; and Thao, who is Hmong American, kept bystanders back.

Kueng and Thao are also accused of failing to intervene to stop the May 25, 2020, killing, which triggered protests worldwide and a reexamination of racism and policing.

The charges allege that the officers’ actions resulted in Floyd’s death.

Longo said an officer’s “duty of care” for people in custody “is absolute” because they are restrained cannot care for themselves. He also said an officer has a duty to take “affirmative steps” to stop another officer from using excessive force.

“The term intervene is a verb, it’s an action word. And it requires an act. And what you do is you stop the behavior,” he said.

When a defense attorney noted the Minneapolis Police Department’s training policy says an officer must attempt to intervene, Longo responded: “An attempt requires some affirmative act.”

Prosecutors began presenting their case on Jan. 24 and have said they expect to rest Monday. Defense attorneys will then start presenting witnesses. The attorney for Lane has said his client will testify. Attorneys for Thao and Kueng haven’t said if they will.

The trial has included testimony from bystanders, doctors, police officers, an FBI agent and others. Prosecutors also have played bystander and body camera videos that show Floyd being restrained and eventually becoming motionless before being put into an ambulance.

Testimony has included information about police training, and what the officers should have known about their duty to intervene and their responsibility to provide Floyd with medical care.

Despite efforts to keep the case on track, Judge Paul Magnuson ordered a three-day pause after one of the defendants tested positive for COVID-19.

One of the prosecution’s key arguments has been that the officers were trained to provide medical aid in emergencies, and that Floyd’s situation had become so serious that even bystanders, including children with no medical training, knew something was wrong.

On Friday, Alyssa Funari testified that when she saw three officers on top of a man in the street, she parked her car and started recording because she had a “gut feeling” something was wrong.

“I instantly knew that he was in distress. … He was moving, making facial expressions that he was in pain,” said Funari, who was 17 at the time and is now 19. “He was telling us that he was in pain.”

“I observed that over time he was slowly being less vocal and he was closing his eyes,” she added. “He wasn’t able to tell us that he was in pain anymore. He was just accepting it.”

Chauvin, who is white, was convicted of murder and manslaughter in state court last year and later pleaded guilty to a federal civil rights charge.

Lane, Kueng and Thao also face a separate state trial in June on charges alleging that they aided and abetted murder and manslaughter.

(AP)