Derek Chauvin violated Minneapolis Police Department rules and its ethics code on respecting the "sanctity of life" during the deadly arrest of George Floyd last May, the city's police chief testified at the former officer's murder trial on Monday.

"It's not part of our training, and it is certainly not part of our ethics and our values," said Chief Medaria Arradondo, referring to how Chauvin, who is white, held his knee on the neck of Floyd, a 46-year-old Black man, for more than nine minutes. A bystander's video of Floyd's dying moments sparked global protests against police brutality.

Over 3.5 hours of testimony, Arradondo, the first Black person to lead the city's police, disputed the defense's claim that Chauvin, who has pleaded not guilty to murder and manslaughter charges, was following the training he had received in his 19 years on the force.

In opening statements last week, a prosecutor told the jury that it would hear from Arradondo, who would not "mince words."Last year, the chief released a statement castigating Chauvin, saying: "This was murder - it wasn't a lack of training."

"I vehemently disagree that that was appropriate use of force for that situation on May 25," he said On Monday.

He said officers are trained to treat people with dignity and are sworn to uphold the "sanctity of life." They are trained in basic first aid and given annual refresher courses, be it in tying a tourniquet to a bleeding gunshot victim or using a naloxone inhaler to reverse an opioid overdose.

Chauvin failed to follow his training in several respects, Arradondo said. He could tell from Floyd's grimaces that Chauvin was using more than the maximum "light-to-moderate" pressure an officer is allowed to use on someone's neck. 

"It's contrary to our training to indefinitely place your knee on a prone, handcuffed individual for an indefinite period of time," he said, echoing testimony last week by the department's most senior homicide investigator who called Chauvin's use of force "totally unacceptable."

In cross-examination, Eric Nelson, Chauvin's lead lawyer, began with getting Arradondo to say it had been "many years" since he himself had made an arrest.

That Floyd was taken into custody at all was unusual, Arradondo said, given it was a non-violent misdemeanor.

"We are often times the first face of government our community will see, and we will often meet them at their worst moments," Arradondo told the jury when asked by a prosecutor to describe the meaning of the badge the city's roughly 700 sworn officers wear. "That has to count for something."