April 5 (UPI) -- Former police officer Derek Chauvin disregarded his own training when he kept a knee on the neck of George Floyd for more than 9 minutes last year, Minneapolis Police Chief Medaria Arradondo testified Monday.
Arradondo, responding to prosecutors' questions at Chauvin's murder trial in Minneapolis, said the fired officer disregarded departmental policy on the use of force with his actions on May 25, 2020, when a handcuffed Floyd died while pinned face-down under his knee.
"Once Mr. Floyd had stopped resisting, and certainly once he was in distress and trying to verbalize that, that should have stopped," the chief said, adding Chauvin's continued use of force "in no way shape or form is anything that is by policy, part of our training and is certainly not part of our ethics or values."
Arradondo's potentially damaging testimony came as prosecutors tried to show that Chauvin's actions during Floyd's arrest violated police procedure.
Chauvin and three other officers arrested Floyd after an employee at a convenience store said he tried to pay with a counterfeit $20 bill. During the arrest, Chauvin forced him into a prone position on the ground and knelt on the back of his neck for 9 minutes and 29 seconds.
Explaining the department's tactics for use of force, the chief said kneeling on suspect's neck for that long is a violation of protocols designed to de-escalate potentially violent situations as well as the department's mission statements calling for compassion.
"That action is not de-escalation, and when we talk about the framework of our sanctity of life and when we talk about the principles and values we have, that action goes contrary to what we're talking about," he said.
The chief fired Chauvin and three other officers the day after Floyd died.
Arradondo also testified in the trial of ex-Minneapolis police officer Mohamed Noor, who was convicted of killing Justine Ruszczyk Damond in 2017.
His testimony highlighted Monday's proceedings as the Chauvin trial began its second week in Hennepin County District Court.
Earlier, Dr. Bradford Wankhede Langenfeld, the emergency room doctor who pronounced Floyd dead, testified that the leading theory for the cause of his death was "oxygen deficiency," or asphyxia.
"That was one of the more likely possibilities," he said. "I felt at the time based on information I had, it was more likely than the other possibilities."
Langenfeld, who was a senior resident at Minneapolis' Hennepin County Medical Center at the time of Floyd's death last May, said Floyd likely died from a lack of oxygen, not a heart attack.
The defense has argued that Floyd had underlying heart disease that contributed to his death, but prosecutors contend that he was asphyxiated by Chauvin.
Langenfeld also ruled out "excited delirium" as a cause of death, because paramedics at the scene did not report signs of the condition, such as heavy sweating, also adding that there was no indication that Floyd died of a drug overdose.
He testified that paramedics who took Floyd to the hospital reported that he had not received any CPR. Last week, those paramedics testified that they couldn't find Floyd's pulse and Langenfeld said they found no evidence of heart attack.
The doctor said he pronounced Floyd dead after about 30 minutes of treatment at the hospital and that he'd been in cardiac arrest for more than an hour.
Jurors heard from 19 witnesses last week, including several who were present during Floyd's death and gave emotional testimony in describing the scene and their attempts to intervene.
Last week, Chauvin's former supervisor and other officers testified about police training and the officers' use of force against Floyd. Minneapolis Police Lt. Richard Zimmerman said Friday that kneeling on the neck of a suspect is potentially lethal and called Chauvin's use of force on Floyd "totally unnecessary."
Zimmerman also said in testimony last week that officers should have stopped restraining Floyd after he was handcuffed.
Defense attorney Eric Nelson has sought to convince jurors that drugs contributed to Floyd's death, not Chauvin's actions.
Also testifying last week was the clerk of the store who called police about Floyd's possibly counterfeit money, who told the court he felt some regret about the confrontation.
The jury can convict Chauvin of second- or third-degree murder, or second-degree manslaughter. The trial is expected to last around four weeks. Chauvin has pleaded not guilty.