They should have stopped Derek Chauvin, a fellow officer, from putting his knee on the neck of the Black man. The head of the Minneapolis Police Department’s Homicide Unit testified Thursday.

“If you observe another officer using too many force or doing something illegally, you should intervene and stop it,” Lt. Richard Zimmerman said during the federal trial of former officers J. Alexander Kueng and Thomas Lane.

He said that duty could also include intervening to provide first aid to an officer who fails to do so, or moving an officer out of the way when necessary.

Zimmerman was asked what Chauvin was doing to make it so significant. He replied, “The knee on his neck — the officers should’ve intervened at this point and stopped it.” … It can even be fatal.

Thao, Lane, and Kueng are accused of denying Floyd, 46, his civil rights. He was handcuffed, facedown, with Chauvin’s knee pressing onto his neck , for 9 1/2 minutes, May 25, 2020. Kueng placed Floyd on his back, Lane supported him with his legs and Thao kept the rest of the bystanders away.

Kueng and Thao were also accused of failing intervene to stop the murder, which triggered protests around the world and a reexamination on racism and police brutality. Earl Gray, Lane’s lawyer, stated during Zimmerman’s testimony that his client was not charged with failing intervene.

Zimmerman joined the department in 1985. He said that he has been aware of the obligation to intervene since his first 41-years as a law enforcement officer. Zimmerman was also a witness in the state trial of Chauvin last year, which resulted in murder convictions and manslaughter convictions. He stated that Floyd was not required to keel on his neck.

The defense has pointed to Chauvin as the most senior officer on the scene. They also argued that Lane, Kueng and Thao were rookies. Thao had been with Thao for around eight years.

Zimmerman stated that rank and seniority do not change the duty to interfere. This policy applies to all officers in the city, from the chief to the lowest.

He said, “We all wear one badge.”

Zimmerman also spoke with officers about his interviews immediately following Floyd’s death.

Samantha Trepel, the Department of Justice civil right division prosecutor, showed a portion of Lane’s body camera video. It showed Zimmerman questioning Lane and Kueng about what had happened. After responding to a report that someone had passed a fake $20 bill, they recounted parts of their struggle to get Floyd into their squad car.

“He seemed to be on some sort of high.” Lane says that he was fighting all the time.

Zimmerman stated that Kueng and Lane told him nothing about Floyd being kept on the ground, without rolling him over, Chauvin keeping his knee on Chauvin’s neck, about them not being able to find a pulse or Lane giving CPR in an ambulance.

Trepel inquired if the officers’ duty to be truthful was applicable to Lane and Kueng’s account. Zimmerman confirmed that it was.

Earl Gray, Lane’s lawyer, asked Lane if they should roll Floyd up and was rebuffed. Concerns that Floyd might be feeling “excited delirium”

Zimmerman said Lane told him, “I think that he’s passingout” and recalled Kueng telling Lane that he couldn’t find a pulse.

Gray said, “They’ve been doing pretty much all that they’re being taught.”

Zimmerman agreed to this point, but Trepel asked him more.

Zimmerman stated, “Intervening is doing something, not suggesting.”

Unter cross-examination by Thomas Plunkett (kueng’s attorney), Zimmerman admitted to telling FBI investigators that he felt poorly about Chauvin.

Zimmerman agreed with Chauvin that a jerk shouldn’t be a field trainer officer.

Kueng, who are Black, Lane, a white man, and Thao who is Hmong American were charged with willfully denying Floyd his constitutional rights, while they were acting under the authority of the government. According to the charges, Floyd died as a result of officers’ actions.

Chauvin, a white man , pleaded guilty to a federal civil rights offense in December.

In June, Lane, Kueng, and Thao will also be facing a separate state court on charges that they aid and abet murder and manslaughter.