A confluence of different factors – fentanyl intoxication, pre-existing heart disease, potential exposure to carbon monoxide from a police car’s tailpipe, and officers’ restraints – all had an impact on Mr Floyd’s death, argued Dr David Fowler, former Maryland chief medical examiner and an expert witness for the defence.
“When you put all of those together, it’s very difficult to say which of those is most accurate,” Dr Fowler said, as part of his day-long turn on the witness stand. “I would fall back to ‘undetermined’ in this particular case.”
Assessing the exact cause of death is central to the trial of Mr Chauvin, a former Minneapolis police officer charged with murder and manslaughter after kneeling on the neck of Mr Floyd, an unarmed Black man, for more than nine minutes last May during an arrest over a counterfeit $20 bill.
Dr Fowler’s argument goes against the findings of Hennepin County medical examiner Andrew Baker. Dr Baker concluded the death was a homicide last year in an autopsy, and reiterated this holding in a recent testimony, arguing police restraints were the primary cause of death, while other factors like cardiac problems and intoxication contributed, too.
“Mr Floyd’s use of fentanyl did not cause the subdual or neck restraint,” Dr Baker testified last week. “His heart disease did not cause the subdual or the neck restraint.”
On Wednesday, Dr Fowler, the Maryland pathologist, said that the prolonged struggle between officers and Mr Floyd didn’t rule out a sudden cardiac arrest, as other medical experts have testified in this case previously.” Cardiac arrest is not absolutely irreversible and is not synonymous with person always passing away,” he said. “For instance in this case, official pronunciation of death was done in the hospital. Frankly, he was dead long before that, but the moment of death is not something you can easily document.”
He and a panel of forensic pathologists and other medical experts worked to reach this opinion, he added, while arguing a lack of bruising to the neck or back strengthened his analysis that heart problems were the prime culprit. The state pushed back on this point.
“The majority of cases where somebody dies of asphyxia are very subtle, and in fact no traumatic manifestations are visible at all,” prosecutor Jerry Blackwell said, echoing the previous testimony of medical experts so far. Dr Fowler agreed, though said every case is different.
The state also took issue with Dr Fowler’s argument that various lab and real-world studies of police restraints suggested that the health risks of subjects being pushed chest-first against the ground weren’t “a significant issue”.
Mr Blackwell noted that none of these studies replicated the exact conditions Mr Floyd was put under: multiple officers on top of someone with heart disease and opioids in his system, pressed against hard asphalt.
Most medical experts in the trial so far have argued the ultimate cause of death was suffocation, with the other factors Dr Fowler mentioned playing a secondary role.
“Mr Floyd died from a low level of oxygen,” Dr Martin Tobin, a lung expert, testified last week. “It’s like the left side is in a vice. It’s totally being totally pushed in, squeezed in from each side,” he added.
He added that fentanyl is a powerful opioid that causes people to slow their breathing and appear woozy just before an overdose. Mr Floyd, however, continued taking breaths at a normal rate for minutes before finally passing out.
“It tells you that there isn’t fentanyl on board that is affecting his respiratory centres,” Dr Tobin said.
Others pointed to the prolonged struggle between Mr Floyd and officers as evidence that he didn’t die from a sudden cardiac problem, but rather was killed by police.
“Mr Floyd died of positional asphyxia, which is a fancy way of saying he died because he had no oxygen in his body,” said Dr Bill Smock, a forensic medical specialist and police training doctor called by the state. “When the body is deprived of oxygen, in this case from pressure on his chest and back, he gradually succumbed to lower and lower levels of oxygen until it was gone and he died.”
“There was absolutely no evidence at autopsy that suggest George Floyd had a heart attack,” Dr Smock added, arguing an autopsy didn’t turn up suggestions of a blood clot or haemorrhaging in his heart. “A healthy person subjected to what Mr Floyd was subjected to would’ve died as a result,” he added.”
Deciding the ultimate cause is just one of the major questions before jurors in the Chauvin trial. They’ll also be called to decide whether the former officer used excessive force on Mr Floyd given the situation, and whether officers did enough to offer him medical aid once it was clear he was in medical distress.
A number of senior Minneapolis police officers as well as an outside use of force expert called by the state have concluded Mr Chauvin wasn’t following proper training and went overboard with his use of force, and that Mr Chauvin didn’t do enough to intervene as Mr Floyd began dying.
“That person is yours,” lieutenant Richard Zimmerman, a veteran Minneapolis police officer, said at the beginning of the trial. “He’s your responsibility. His safety is your responsibility. His wellbeing is your responsibility.”
Witness testimony is likely to conclude this week, with jury deliberations beginning early next week.
Still, the conversation around police reform and prosecution is just beginning in Minneapolis, as the city reels from the news of another Black man dying in police custody: the Sunday shooting of Daunte Wright, a 20-year-old, during a traffic stop in the Minneapolis suburb of Brooklyn Center.
On Wednesday, authorities filed second-degree manslaughter charges Kim Potter, the officer who shot Mr Wright while, according to officials, she believed she was reaching for her Taser.
Both Ms Potter and the Brooklyn Center police chief resigned on Tuesday, and protests continue across the Twin Cities, where police and National Guard troops have been accused of using excessive force and chemical weapons against protestors and journalists.