Lt. Johnny Mercil, the Minneapolis Police Department's use-of-force instructor, testified on Tuesday at former Officer Derek Chauvin's trial that when officers are taught ways to restrain aggressive suspects, they are shown how to place their knee on a back or shoulder and told to "stay away from the neck when possible".
Yang said police are trained to use principles such as neutrality, respect and trust in crisis intervention situations, and how to spot and interact with suspects going through a crisis. Prosecutor Steve Schleicher said records show that Chauvin attended a 40-hour course on the method in 2016.
Bradford Langenfeld, who was a senior resident on duty that night at Hennepin County Medical Centre and tried to resuscitate Mr Floyd, said Mr Floyd's heart had stopped by the time he arrived at the hospital.
Mercil stated, "It's been said, yes".
He also said officers were taught that restraint is considered force and that they must use the least force required because "it's safer and better for everybody involved".
Chauvin's attorney, Eric Nelson, told Cahill he planned to ask Hall whether he gave Floyd any controlled substances and why Hall left Minnesota immediately after the incident. He said officers are not taught to use their legs or knees, though a knee on the neck can happen depending on a person's resistance. Schleicher asked if an officer is to employ such a technique, how long it should be used.
"I would say no", Lieutenant Mercil testified.
Minneapolis Officer Nicole Mackenzie leads the department's EMT unit and she testified that just because someone could talk does not mean they are not having difficulty breathing.
The jury in the trial of Derek Chauvin heard his prolonged use of force broke police protocol.
Chauvin, 45, is facing murder and manslaughter charges in the death of George Floyd, a 46-year-old unarmed Black man who died on May 25, 2020, while being arrested in Minneapolis on suspicion of using a fake $20 bill.
Floyd's treatment by the white officer was captured on widely seen bystander video that sparked protests around the USA that descended into violence in some cases.
Body camera footage shows Hall sitting next to Floyd in the auto when police arrived.
Footage of Mr Chauvin, who is white, kneeling on African-American Mr Floyd's neck for more than nine minutes past year sparked global protests against racism.
Prosecutors are seeking to prove that Floyd's death was due to asphyxiation, while Chauvin's defense claims it was due to illegal drugs in Floyd's system.
Nelson has further argued that police at the scene were distracted by what they perceived as a growing and increasingly hostile crowd of onlookers.
Mercil agreed that if an officer is placing body weight with the knee on a person's neck and back that it would decrease their ability to breathe.
On the sixth day of the trial into Mr Chauvin, the chief said his officer was responsible for multiple breaches of duty, namely: that he should have let Mr Floyd up sooner; that the pressure on Mr Floyd's neck did not appear to be light to moderate; that Mr Chauvin failed in his duty to render first aid before the ambulance arrived; and that he violated policy requiring officers to de-escalate tense situations with no or minimal force if they can.
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".