Chief medical examiner takes the stand in George Floyd case

The chief county medical examiner who ruled George Floyd's death a homicide took the stand Friday at former Officer Derek Chauvin's murder trial, saying he did not watch the harrowing video of the arrest before examining Floyd so that he would not be biased by what he saw.

“I was aware that at least one video had gone viral on the Internet, but I intentionally chose not to look at that until I had examined Mr. Floyd,” said Dr. Andrew Baker.

"I did not want to bias my exam by going in with any preconceived notions that might lead me down one pathway or another.”

Baker, the Hennepin County medical examiner, concluded last year that Floyd died from cardiopulmonary arrest — that is, his heart stopped — complicated by the way police restrained him and compressed his neck as the 46-year-old Black man lay on the pavement last May.

Another medical expert Friday blamed Floyd's death on the way police held him down, as Chauvin's attorney pressed the witness with hypothetical questions and other means to suggest that Floyd's drug use or heart disease killed him.

The testimony of Dr. Lindsey Thomas, a forensic pathologist who retired in 2017 from the Hennepin County Medical Examiner's Office, bolstered the findings of other prosecution experts who have taken the stand at Chauvin's murder trial.

Thomas, who did not work on Floyd's case, said the “primary mechanism of death” was asphyxia, or insufficient oxygen — a conclusion she said she reached mostly from video that showed Floyd struggling to breathe as Chauvin knelt on his neck and two other Minneapolis police officers helped hold him down.

“This is a death where both the heart and lungs stopped working. The point is, it's due to law enforcement subdual, restraint and compression,” Thomas said.

The autopsy itself ruled out heart attack, aneurysm and other causes, and Thomas said it was not a drug overdose death, either.

“There is no evidence to suggest he would have died that night except for the interactions with law enforcement,” she testified.

Thomas said she agreed with Baker's findings, but she went further in specifying Floyd died of asphyxia. She said that there was nothing in Floyd's autopsy that noted that, but she said that is not uncommon.

Chauvin, 45, is charged with murder and manslaughter in Floyd's death May 25. Floyd was arrested outside a neighborhood market after being accused of trying to pass a counterfeit $20 bill.

Bystander video of Floyd crying that he couldn't breathe as onlookers yelled at the white officer to get off him sparked protests and scattered violence around the U.S.

Chauvin attorney Eric Nelson has argued that the now-fired white officer did what he was trained to do and was not responsible for Floyd's death. Floyd had high blood pressure and heart disease, and an autopsy found fentanyl and methamphetamine in his system.

Under cross-examination by Nelson, Thomas said she believed Floyd's heart was “slightly” enlarged.

Nelson asked Thomas about what could cause a heart to suddenly stop beating, noting that Floyd's bigger heart needed more blood and was working hard in a moment of stress and adrenaline, and that one of his arteries had a 90% blockage.

Thomas said any blockage over 70 per cent to 75 per cent could be used to explain death, in the absence of another cause. But she also said some people can live just fine with an artery that is fully blocked.

The defense attorney pressed Thomas by posing a hypothetical question.

“Let's assume you found Mr. Floyd dead in his residence. No police involvement, no drugs, right?. The only thing you found would be these facts about his heart. What would you conclude to be the cause of death?” Nelson asked.

“In that very narrow set of circumstances, I would probably conclude that the cause of death was his heart disease,” Thomas replied.

She also agreed that fentanyl can slow a person's breathing and that methamphetamine can cause the heart to work harder and cause cardiac arrhythmia — a potentially lethal heart rhythm disturbance.

In response to another hypothetical posed by Nelson, she agreed that she would certify Floyd's death as an overdose if there were no other explanations.

But during re-questioning, prosecutor Jerry Blackwell ridiculed the defense attorney's hypotheticals and quickly got Thomas to repeat that the cause of Floyd's death was the restraint by police.

“Aren't those questions a lot like asking, Mrs. Lincoln, if we take John Wilkes Booth out of this ...,'” Blackwell began, before Nelson objected.

Floyd's death certificate listed certain contributing conditions: narrowed arteries, high blood pressure, fentanyl intoxication and recent methamphetamine use. But Thomas said that they did not directly cause his death and that such factors are commonly included on death certificates to inform public health officials.

Instead, Floyd died because the position of his body — lying on his stomach, his hands cuffed behind his back and officers pressing their body weight into him — made it impossible to breathe, said Thomas, who called Floyd's death “so well-documented” because of extensive video evidence.