MINNEAPOLIS — Four years before George Floyd’s death, Officer Derek Chauvin took a 40-hour course on crisis intervention that included training on how to recognize people in crisis and how to use de-escalation techniques to calm them down, the jury at Chauvin’s murder trial was told Tuesday.

Derek Chauvin

Sgt. Ker Yang, the Minneapolis police official in charge of training officers on handling crises, became the latest member of the department to take the stand as prosecutors try to prove that Chauvin failed to follow his training when he put his knee on Floyd’s neck.

Yang said on Day Seven of Chauvin’s trial that officers are taught to make critical decisions in dealing with people in crisis, including those suffering mental problems or the effects of drug use, and then defuse the situation. Prosecutor Steve Schleicher said records show that Chauvin attended a course on the method in 2016.

“When we talk about fast-evolving situations … a lot of the time we have the time to slow things down and reevaluate and reassess and go through this model,” Yang said.

Chauvin, 45, is charged with murder and manslaughter in Floyd’s death May 25. The 46-year-old Black man was pinned to the pavement outside a neighborhood market after being accused of trying to pass a counterfeit $20 bill for a pack of cigarettes.

Floyd’s treatment by the white officer was captured on widely seen bystander video that sparked protests around the U.S. that descended into violence in some cases.

Floyd, who had taken drugs, frantically struggled with officers who tried to put him in their squad car, saying he was claustrophobic. Prosecutors said Chauvin continued to kneel on Floyd’s neck for 9 minutes, 29 seconds, after he was handcuffed behind his back and lying on his stomach, even though Floyd said 27 times that he could not breathe.

Chauvin’s lawyer, Eric Nelson, has argued that Chauvin “did exactly what he had been trained to do over his 19-year career” and that it was Floyd’s use of illegal drugs and his underlying health conditions — not the officer’s knee — that killed him.

Nelson has further argued that police at the scene were distracted by what they perceived as a growing and increasingly hostile crowd of onlookers.

Under questioning from Nelson, Yang testified that people watching an arrest may also be in crisis and that officers have to take in the situation around them as well.

Instead of protecting a fellow officer in what is sometimes called the “blue wall of silence,” some of the most experienced members of the Minneapolis force – including the police chief and the head of the homicide division — have taken the stand to openly condemn Chauvin’s treatment of Floyd.

On Monday, Police Chief Medaria Arrondondo, who called Floyd’s death “murder” soon after it happened, testified that Chauvin had clearly violated department policy on a number of counts and used excessive force.

Arrondondo said continuing to kneel on Floyd’s neck once he was handcuffed behind his back and lying on his belly was “in no way, shape or form” part of department policy or training, “and it is certainly not part of our ethics or our values.”

Arradondo, the city’s first Black chief, fired Chauvin and three other officers the day after Floyd’s death.