Derek Chauvin Trial 4/14/21: Defense expert found Floyd's manner of death to be undetermined, not homicide

On redirect questioning by defense attorney Eric Nelson, Fowler said the larger a person, the more likely they are to inflict injuries or bruising on a person while restraining them. Fowler said it's "very common" to see bruising in cases of death by asphyxia.

Fowler said Chauvin's knee was not obstructing Floyd's carotid artery in his neck, and even if it had obstructed one carotid artery, the second "would continue to supply the brain with enough blood for it to function."

On cross-examination, prosecutor Jerry Blackwell asked whether it's his opinion Chauvin's actions played any role in Floyd's death during his restraint on the ground. After an objection, Blackwell rephrased the question, asking whether Floyd's passing was "coincidental and unrelated to the restraint on the ground." 

The defense again objected. Fowler did not answer either question. Blackwell then concluded his questioning and court recessed for the day.

Blackwell pointed to Fowler's earlier characterization of Floyd's death as "sudden." He asked at what point Floyd died in the more than five minutes between when Floyd was first restrained and when officers found he had no pulse. Fowler clarified that he believes that Floyd suffered a sudden cardiac arrest, but that there could have been a period of time between suffering cardiac arrest and dying.

"The moment of death is not something you can easily document," Fowler said.

Blackwell then asked whether Fowler thought early medical intervention could have saved Floyd's life, and Fowler agreed. Fowler agreed Floyd should have been given immediate medical attention.

Fowler agreed that Floyd had a normal respiratory rate before he died, and someone suffering from a fentanyl overdose would have a lowered respiratory rate. But he qualified his answer by saying it's possible Floyd would have otherwise had a higher respiratory rate because of the stress of the police restraint.

Blackwell also pointed out that Floyd had a low level of methamphetamine in his system. Fowler agreed the pills found in the squad car were obviously not in Floyd's body, and no pills were found in his stomach during autopsy.

"Correct -- whatever the residual amount in those tablets was, was not in his body," Fowler said.

Blackwell honed in on Fowler's testimony that no bruising or injuries were found on Floyd's neck or back. Fowler agreed that in the majority of cases in which someone dies of low oxygen, there are no "traumatic indications" of the cause of death, such as bruising. He agreed that whether or not someone suffered from positional asphyxia can be determined only through investigation, not by autopsy.

"Correct, the scene in formation becomes very important," Fowler testified.

Several medical experts testified for the prosecution that they relied on video evidence to determine that Floyd died of low oxygen due to the police restraint.

Court has resumed session. Dr. David Fowler, the forensic pathologist who testified for the defense, is being cross-examined by prosecutor Jerry Blackwell. Fowler testified earlier that Floyd died of a heart arrhythmia due to his heart disease, but listed several contributing factors, including possible exposure to carbon monoxide from the squad car's exhaust.

Answering questions from Blackwell, Fowler agreed there was no finding of carbon monoxide in Floyd's body because no tests were done. Blackwell then asked Fowler if he knew for a fact that the squad car was running at the time Floyd was restrained. Fowler replied he believed the car was running because he saw water dripping from the tail pipe.

"You simply assumed, seeing something dripping from a tailpipe, that the car had to be on?" Blackwell asked.

""It's not an assumption," Fowler replied. "It's an evaluation that in my mind indicates the vehicle was running."

Fowler testified that Floyd had "so many conflicting potential mechanisms of death" that he considers the manner of death to be undetermined. Floyd's death was previously ruled a homicide by the Hennepin County Medical Examiner, who stood by the classification during his testimony.

Medical examiners in determining manner of death can choose one of five classifications -- homicide, natural, accidental, undetermined or suicide.

Fowler walked through how he made the determination, saying being restrained near a source of carbon monoxide and the stress of the police interaction triggering Floyd's "fight or flight" reaction would be considered a homicide. But most circumstances in which drug intoxication contributed to a death would be considered an accident, he said. Floyd also had "significant natural heart disease" and a paraganglioma tumor which may have secreted adrenaline, possibly further compromising the heart.

"If you put all those together, it's very difficult to say which of these is most accurate," Fowler said. "I would fall back to undetermined."  

Fowler testified Chauvin's knee was not blocking Floyd's airway.

"The placement of the knee was towards the back right side of Mr. Floyd's neck, and the airway is around the front," Fowler said. "It is nowhere near to his airway." 

Fowler testified he could not find evidence in medical literature that Chauvin's knee would have impaired the function of Floyd's hypopharynx, a small area at the bottom of the throat, as a pulmonologist earlier testified for the prosecution.

Fowler testified he did not see evidence on the video that Floyd died of hypoxia, or low oxygen, as the prosecution has argued. He said he would expect to see Floyd become disoriented, confused and incoherent if hypoxia was the cause of death. Fowler said Floyd "goes from pretty much fully functional and coherent to unconscious very rapidly," indicating a sudden cardiac event.

Fowler said a combination of Floyd's heart disease, narrowed blood vessels, drug ingestion and exposure to carbon monoxide were "all acting together and adding to each other and taking away from a different part of the ability to get oxygen into his heart."

"At some point, the heart exhausted its reserves of metabolic supply and went into an arrhythmia, and then stopped pumping blood effectively," Fowler said.

Nelson asked Fowler to describe a study that called into question the dangers of positional asphyxia, with the authors calling it "an interesting hypothesis unsupported by any experimental data." The study involved placing weight on the backs of volunteers who were in the prone position on a gym mat, and found the position had no significant effect. Earlier, medical examiners had testified for the prosecution that the study was flawed because it was not based on real-world scenarios.

Fowler also pointed to another study about knee restraints and transference of weight to the body, based on an experiment using dummies. Based on that, he said Chauvin would have been applying less than 23 percent of his own weight to Floyd's body.

Fowler testified he found no evidence of injury or bruising to Floyd's neck or back.

"It speaks to the amount of force applied to Mr. Floyd was less than enough to bruise him," Fowler said.

Fowler is now testifying about the effect of carbon monoxide on the body, noting Floyd's position as he was being restrained near the running squad car's exhaust pipe. Fowler said he doesn't think carbon monoxide poisoning caused Floyd's death, but earlier he said it is, in his opinion, one of the contributing factors.

Fowler said carbon monoxide is an "extremely toxic gas" that decreases a person's oxygen-carrying capacity and in high levels can cause death. Fowler said "people with significant heart disease and reduced capacity in the heart" can be adversely affected by lower levels.

"It takes away from the important factor of getting blood to his heart muscle -- this is just another insult, another brick in the wall unfortunately, for the circumstances," Fowler said.  

Fowler testified that Floyd had an enlarged heart, which required more oxygen, and narrowed arteries -- some up to 90% -- that would result in reduced blood supply to his heart. He said the enlarged heart, caused by hypertensive cardiovascular disease, and narrowed arteries can increase someone's risk for sudden death.

Fowler said that arrhythmias can result when the heart's blood supply needs are not met. Methamphetamine sensitizes the heart to arrhythmia, increases the heart rate and causes blood vessels to narrow, Fowler said. Physical exertion, he said, increases the heart's demand for oxygenated blood. 

"The more the individual is stressed, both physical and in other ways, the more the demand on the heart is going to increase," Fowler said. 

Fowler said the body's "fight or flight" response increases adrenaline, which also narrows the arteries.

"There's a potential of the adrenaline and methamphetamine further narrowing those arteries in the heart, as well as arteries elsewhere in the body, restricting blood flow," Fowler said.

Fowler noted that Floyd's blood pressure after his 2019 arrest was "markedly elevated," possibly due to his hypertension being "out of control" or due to the stress of the police interaction.

Fowler testified his review of the case for the defense included Floyd's past medical records, hospital and ambulance records, police records, toxicology information, and multiple videos including bodyworn cameras, surveillance videos and bystander videos.

Fowler testified he believes Floyd died of a sudden cardiac arrhythmia due to his underlying heart disease during his restraint and subdual by police. He said contributing significant factors included Floyd's ingestion of fentanyl and methamphetamine, exposure to vehicle exhaust and possible carbon monoxide poisoning, and Floyd's paraganglioma, a tumor in his pelvis.

"All of those combined to cause Mr. Floyd's death," Fowler said.

Defense attorney Eric Nelson has called forensic pathologist David Fowler to the stand. Now retired, Fowler was formerly employed by Maryland's Office of Chief Medical Examiner.

Floyd's friend Morries Hall, who was in the car with Floyd before his fatal arrest, was questioned by the judge before the jury was called into the courtroom. Hall was subpoenaed to testify in the case, but his lawyer has argued that because the defense has suggested Hall sold Floyd drugs and that Floyd died of a drug overdose, his testimony would leave him vulnerable to potential criminal charges under Minnesota's broad third-degree murder statute. 

Hall said he is not willing to testify because he is fearful of incriminating himself. Judge Peter Cahill found that Hall had a valid Fifth Amendment privilege, and quashed the subpoena. 

Judge Peter Cahill denied a motion for a judgment of acquittal by the defense after court resumed session Wednesday.

Defense attorney Eric Nelson argued the judge should acquit Chauvin without sending the case to the jury because the state has not proven its case. Nelson said the state has failed to show how Floyd died and has presented a series of conflicting opinions on whether the use of force was unreasonable. The state opposed the motion, which is fairly typical in criminal proceedings following the conclusion of the prosecution's case.

Also on Tuesday, Minneapolis Park Police officer Peter Chang testified he responded to the scene. Chang said he saw former officers J. Alexander Kueng and Thomas Lane pinning Floyd against the squad car and approached them to see if he could assist. Lane asked him to check out the car Floyd had been driving.

Defense attorney Eric Nelson played Chang's bodycam video in court. It shows Chang approaching Floyd's friends, Shawanda Hill and Morries Hall, standing near Floyd's car across the street and around the corner. Chang is heard telling them to step away from the car and "stay put." 

As a crowd begins to grow, Hill and Hall become more concerned about Floyd and ask what's happening. There was apparently not a clear line of sight to where Floyd was being restrained on the ground from the corner where Hill and Hall were standing with Chang. Hill is heard saying, "They did something to him --- people are taking pictures over there."

Later, Hill asked Chang, "Can I just see what y'all did to him? He's on the ground and everything." 

"He's on the ground? Where?" Hall asked Hill. 

Hall is heard yelling, "Why is he going to the hospital?"

Responding to questions from Nelson, Chang said the crowd was "very aggressive towards the officers."

"I was focused on [Floyd's] car, but it distracted me, and I was concerned for the officers' safety, too," Chang said.

Barry Brodd, a former police trainer, testified as a use-of-force expert after analyzing Chauvin's actions for the defense.

He said he focused his review on the videos, use-of-force policies and training. Brodd said he believes Chauvin was justified in restraining Floyd, acting with objective reasonableness and following Minneapolis police training. He said he believes Floyd was "actively resisting" officers by struggling as he was restrained on the ground.

Retired Minneapolis officer Scott Creighton testified he pulled his weapon when Floyd wouldn't show him his hands during a traffic stop in 2019. In body camera video played in court, Creighton raises his voice and uses an expletive as he commands Floyd, a passenger in a car he pulled over, to show him his hands. Floyd can be heard asking the officer not to shoot him. 

"I'm not going to shoot you if you put your hands on the dash, it's the last time I'm going to tell you, it's simple," Creighton says on the video. "He keeps moving his hands around, he won't listen to what I have to say."

Later, a paramedic testified Floyd admitted he had swallowed pills during the arrest, and said his blood pressure was so high she sent him to the hospital. Watch a recap of earlier testimony below.    

Chauvin is charged with second-degree murder, third-degree murder and second-degree manslaughter.

In order to convict Chauvin of second-degree murder, prosecutors will need to prove beyond a reasonable doubt that Chauvin caused Floyd's death while committing or attempting to commit a related felony, in this case third-degree assault. To convict the former officer of third-degree murder, prosecutors must convince the jury that Chauvin caused Floyd's death during an act that was "eminently dangerous to others and evincing a depraved mind, without regard for human life." 

The third-degree charge was initially dropped by Judge Cahill, but was re-instated earlier this month after an appeals court handed a win to prosecutors.

To convict Chauvin of second-degree manslaughter, prosecutors will need to prove beyond a reasonable doubt that Chauvin caused Floyd's death by "culpable negligence," meaning he created unreasonable risk and consciously took a chance of causing death or serious harm.

Prosecutors do not need to prove that Chauvin intended to cause Floyd's death. Since police officers are authorized to use force, prosecutors must prove that the force Chauvin used against Floyd was unlawful.

In Minnesota, second-degree murder carries a maximum sentence of 40 years in prison. Third-degree murder is punishable by up to 25 years. Second-degree manslaughter carries a maximum prison term of 10 years.