The Prosecution Presented Compelling Evidence That Derek Chauvin Killed George Floyd by Using Excessive Force

The defense will have to cast doubt on at least one of those claims.

Closing out its presentation of witnesses in Derek Chauvin's murder trial yesterday, the prosecution underlined two essential elements of its case: that the former Minneapolis police officer's actions caused George Floyd's death last May and that his use of force was not justified in the circumstances. The defense, which began calling witnesses today, will try to cast doubt on both of those claims. Defense attorney Eric Nelson can win an acquittal if he persuades the jurors that prosecutors have failed to prove at least one of those propositions beyond a reasonable doubt.

Chicago cardiologist Jonathan Rich yesterday agreed with other medical witnesses that Floyd "died from a cardiopulmonary arrest…caused by low oxygen levels." He also agreed that Floyd could not get enough oxygen because his prolonged prone restraint, during which Chauvin pinned him facedown to the pavement for nine and a half minutes, made it difficult to breathe. "Because of the position that he was subjected to," he said, Floyd's heart "did not have enough oxygen."

Like other prosecution witnesses, Rich said two theories the defense has floated are not supported by the evidence. "I can state with a high degree of medical certainty" that Floyd "did not die from a primary cardiac event and did not die from a drug overdose," he said.

Rich added that the three officers who were holding Floyd down—Chauvin, J. Alexander Kueng, and Thomas Lane—missed several opportunities to save his life. When one of the cops remarked that Floyd seemed to be passing out, Rich said, "that would have been an opportunity to quickly relieve him from that position of not getting enough oxygen." When Lane suggested that Floyd should be turned from his stomach to his side, Chauvin said, "Leave him." And when Kueng reported that Floyd had no detectable pulse, Rich said, the officers should have immediately begun CPR. "I believe that Mr. George Floyd's death was absolutely preventable," he said.

Hennepin County Chief Medical Examiner Andrew Baker, who testified on Friday, agrees that Floyd suffered "cardiopulmonary arrest" as a result of "law enforcement subdual, restraint, and neck compression." In Baker's view, the use of force against Floyd fatally interacted with his "very severe underlying heart disease." But he did not rule out that breathing difficulty may have contributed to Floyd's death, saying, "I would defer to a pulmonologist."

Chicago pulmonologist Martin Tobin, who testified last Thursday, concluded that "Floyd died from a low level of oxygen" caused by obstructed breathing, which ultimately "caused his heart to stop." Tobin said even a perfectly healthy person would have died in these circumstances.

Nelson, Chauvin's lawyer, argues that Floyd "died of a cardiac arrhythmia that occurred as a result of hypertension, his coronary disease, the ingestion of methamphetamine and fentanyl, and the adrenaline flowing through his body, all of which acted to further compromise an already compromised heart." But even that gloss does not let Chauvin off the hook, since the stress caused by his use of force plausibly contributed to "the adrenaline flowing through [Floyd's] body" and the ensuing "cardiac arrhythmia."

University of South Carolina law professor Seth Stoughton, a former police officer, yesterday agreed with other use-of-force experts that Floyd's prolonged prone restraint was not objectively reasonable. "No reasonable officer would have believed that that was an appropriate, acceptable, or reasonable use of force," he said.

Floyd resisted Kueng and Lane when they tried to place him in their squad car after arresting him for using a counterfeit $20 bill to buy cigarettes. He said he was claustrophobic, complained that he could not breathe, and asked to ride in the front seat. But once Kueng and Lane pulled him out of the car, he stopped struggling and thanked them, at which point the three officers tackled Floyd, who was already handcuffed, and pinned him to the ground.

Judging from the video record of the encounter, Stoughton said, Floyd "does not appear to have the intention to assault or attack the officers." He said the use of force was even more manifestly unreasonable after Floyd became unresponsive. "Somebody who does not have a pulse does not present a threat in any way," he noted.

So far Nelson's argument that Chauvin's use of force was appropriate has been based mainly on Floyd's prior struggle with Kueng and Lane, which does not show that Floyd posed a threat after he was out of the squad car, and the suggestion that Floyd may have continued to resist in ways that are not visible in the videos. Nelson also has repeatedly argued that Chauvin and his colleagues were distracted by the bystanders who criticized the way the cops were treating Floyd.

Like Los Angeles Police Department Sgt. Jody Stiger, another use-of-force expert, Stoughton questioned the notion that the bystanders posed a threat to the officers. He noted that the cops yelled responses to their criticism, which suggests they were not worried about possible violence. Furthermore, the officers were plainly aware of Floyd's complaints that he could not breathe, which they repeatedly dismissed in exchanges with him and the bystanders, and they clearly noticed that Floyd had stopped moving and talking, which is what prompted Kueng to check his pulse. In any event, as Stiger noted, the behavior of bystanders cannot legally justify the use of force against Floyd if it was otherwise excessive.