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Defense Cross-Examines Forensic Pathologist in Chauvin Trial; Prosecution Questions Forensic Pathologist in Chauvin Trial; Forensic Pathologist Says, Video Evidence was Key. Aired 1-1:30p ET

Aired April 9, 2021 - 13:00   ET



ERIC NELSON, DEFENSE ATTORNEY: Very often, there are I.V.s that are placed in a person, right?


NELSON: And those I.V.s contain saline.


NELSON: And saline can ultimately dilute or decrease to some degree the amount of controlled substances that would be -- as they would be measured?

THOMAS: That's a theoretical possibility.

NELSON: You would agree that fentanyl is a respiratory depressant, right?


NELSON: It slows breathing and lowers oxygen in the blood?


NELSON: Does the fact that there's more fentanyl in his blood mean that he took it some time ago?

THOMAS: Yes, but by some time, that's -- that's a very vague -- yes.

NELSON: So, long enough in the past to start metabolizing.

THOMAS: Exactly, exactly.

NELSON: But does it exclude him taking fentanyl more acutely or more recently in time?

THOMAS: There's no way really of knowing the timing.

NELSON: Fentanyl depressing the respiratory system can also act with the coronary artery -- can interact with coronary vessel disease, correct? THOMAS: Can you clarify that? I'm sorry.

NELSON: Does fentanyl's depression of the respiratory system also act with coronary artery vessel disease and oxygen and carbon dioxide to reduce the supply of its supply to the heart?

THOMAS: Oh, so as fentanyl may lead to a gradual progression of slowing breathing, and ultimately decrease the oxygen, that would apply to oxygen to the brain as well as to the heart. Is that what you're -- yes.

NELSON: And it would likewise increase the carbon dioxide in the blood?

THOMAS: Yes. I mean, anything that decreases respiration decreases that exchange.

NELSON: And so as that exchange process is happening, right, you're not taking in the oxygen, you're likewise not expelling the carbon dioxide, right?

THOMAS: Right.

NELSON: And thus the carbon dioxide will increase because you're not expelling it, right?

THOMAS: Correct.

NELSON: You would agree that methamphetamine is a stimulant, right?

THOMAS: Correct.

NELSON: And that can cause a cardiac arrhythmia?

THOMAS: It can.

NELSON: And it can increase a person's heart rate, right?

THOMAS: It can, or cannot.

NELSON: And you testified before that methamphetamine, there's no safe level of methamphetamine, right?

THOMAS: Correct.

NELSON: So the fact that methamphetamine is at a lower toxicological standard doesn't somehow make it safe?

THOMAS: Right.

NELSON: It doesn't exclude the possibility that it could increase the heart rate?

THOMAS: It could or not.

NELSON: The -- in terms of the evidence in this case were you made aware that drugs were found in the backseat of the squad car?


NELSON: And that those drugs contained the DNA of Mr. Floyd?


NELSON: And that those drugs were at least, to some degree, partially dissolved?


NELSON: And that those drugs were fentanyl -- a mixture of fentanyl and methamphetamine?


NELSON: Based on toxicology in this case, did you see any metabolic byproduct of methamphetamine?


NELSON: And so that means the methamphetamine was taken more acutely or recently in time?

THOMAS: Probably. I mean, there's lots of variables.

NELSON: So, again, just kind of taking into consideration removing certain variables, right, you find a person at home, no struggle with the police, right, and you -- the person doesn't have a heart problem but you find fentanyl and methamphetamine in this person's system at the levels that they're at, would you certify this as an overdose?

THOMAS: Again, in the absence of any of these other realities, yes, I could consider that to be an overdose.

NELSON: And the level of fentanyl in a person, again in this hypothetical scenario, there are deaths certified as drug overdoses significantly lower than 11 nanograms per milliliter?


THOMAS: Lower, higher, it's got a huge range, yes.

NELSON: As low, I believe, as 3 percent, or 3 nanograms per milliliter?


NELSON: So the ingestion of drugs is unique to that individual's body, right?

THOMAS: Right.

NELSON: Your honor, I have no further questions.


JERRY BLACKWELL, PROSECUTING ATTORNEY: Dr. Thomas, a few things I'd like to try to clarify with you.

THOMAS: Thank you.

BLACKWELL: You were asked a number of questions that were to the effect that if we take the police subdual, restraint and neck compression out of this, what would you conclude Mr. Floyd's cause of death to have been. Remember those questions?

THOMAS: Oh, yes.

BLACKWELL: Aren't those questions a lot like asking, Mrs. Lincoln, if we take John Wilkes Booth out of this --

NELSON: Objection, argumentative.

CAHILL: It's argumentative, sustained.

BLACKWELL: Dr. Thomas, if we put the police subdual, compression and neck compression into this restraint and neck compression into this, what was the cause, the manner of death for Mr. George Floyd?

THOMAS: The cause of death was the law enforcement subdual, restraint and compression and the manner of death is homicide.

BLACKWELL: Does it make any sense to you whatsoever from the standpoint of trying to assess cause and manner of death for Mr. Floyd to be answering questions having to do with hypothetically taking the facts of this case out relating to his subdual, restraint and compression?

NELSON: Objection, your honor, argumentative.

CAHILL: You can finish the question.

BLACKWELL: Dr. Thomas, from your standpoint as a forensic pathologist and your analysis of manner and cause of death, would you ever approach an assessment of manner and cause of death by taking out of it the facts that you found relevant and highly pertinent to assessing and determining the manner and cause of death?


BLACKWELL: And in this case those factors are what?

THOMAS: The law enforcement subdual, restraint and compression.

BLACKWELL: And you were asked questions again about fentanyl and meth. Remember those questions?


BLACKWELL: Do you know what quantity of meth was even involved or found in Mr. Floyd's bloodstream? THOMAS: I have the number.

BLACKWELL: Let me ask you a question --

THOMAS: But it was very small, I do know that.

BLACKWELL: So this was the point, you found that it was a very small amount?

THOMAS: Correct.

BLACKWELL: Were you able to assess, based on the amount, what kind of effect, if at all, it would have on the stressor the strain on his heart?

THOMAS: No, there's too much individual variability to correlate one number with one person's reaction.

BLACKWELL: Well, let's see with respect to the fentanyl, if there's a punch line we can get to with respect to fentanyl. Fentanyl has been discussed with you, Dr. Thomas, as a respiratory either depressant or suppressant?


BLACKWELL: In order for us to go from fentanyl to death, in the middle, there are certain symptoms and responses and reactions a person would have who's suffering from fentanyl overdose or intoxication.


BLACKWELL: If the person doesn't have those symptoms, those indicators, then would you feel that it's possible even to conclude that they are suffering from fentanyl intoxication or overdose?

THOMAS: No. If there's no signs of fentanyl overdose, then it makes no sense to conclude that there was an overdose from fentanyl.

BLACKWELL: And to be clear for the ladies and gentlemen of the jury, what are those symptoms of fentanyl overdose or intoxication?

THOMAS: So, fentanyl is an opioid.


It's like morphine or heroin. And it causes slowing -- well, first of all, it's a potent pain medication and given mostly for that, but it also can cause slowing of the respiratory rate in a very gradual, peaceful, non-struggle kind of way, what is described as people just fall asleep and may just kind of slump gradually over because they very peacefully stop breathing, or it slows and then eventually stops.

BLACKWELL: And they fall into a sleep out of which they can't even be aroused?

THOMAS: Correct.

BLACKWELL: Would that be also known as a coma?

THOMAS: Yes, ultimately it's a coma.

BLACKWELL: When George Floyd was on the ground for the nine minutes and 29 seconds, was he asleep to the point of not being able to be aroused?

THOMAS: Not for the first half of it, no. And then afterwards, he was completely unresponsive.

BLACKWELL: For the second half, he was unresponsive with no pulse?

THOMAS: Exactly.

BLACKWELL: Was George Floyd, during the nine minutes and 29 seconds ever in a coma that you saw?


BLACKWELL: So when we talk about fentanyl overdose, did you ever see, as applied to George Floyd, during the nine minutes and 29 seconds --

NELSON: Objection.

BLACKWELL: Did you ever see as relates to fentanyl overdose during the nine minutes 29 seconds that he was on the ground and during the subdual and restraint by Mr. Chauvin that he ever exhibited any of the symptoms of fentanyl intoxication?


BLACKWELL: You were asked again quite a few questions about the heart and remember that discussion?


BLACKWELL: I think it was to the effect the heart was slightly enlarged, high blood pressure, narrowing of the coronary arteries, dead heart muscle cells. Do you recall all of that being discussed?


BLACKWELL: In order for us to go from there being issues with damage to the heart to a death from damage to the heart, in the middle, do we have to have certain cardiac events that then lead to death?


BLACKWELL: Would you tell the ladies and gentlemen of the jury if we're going to talk about heart conditions, what are those conditions in the middle that actually lead to death?

THOMAS: Well, what ultimately leads to death is an arrhythmia, an abnormal beating of the heart. And as I described, it's generally a call -- I mean, it's often called a sudden cardiac arrest because it's sudden and someone just drops over.

BLACKWELL: Now, to be clear, when we're talking about these various heart conditions and a sudden cardiac arrest, fatal arrhythmia, did you see any indication of all this discussion about heart conditions that Mr. Floyd ever suffered from a sudden, fatal cardiac arrhythmia as the primary cause of death?


BLACKWELL: Was there any evidence that Mr. Floyd suffered from a heart attack?


BLACKWELL: If you bring to mind what was found during the autopsy, was there any injury found to Mr. Floyd's heart whatsoever?


BLACKWELL: So if we talk about, for example, dead heart muscle cells, any dead heart muscle cells seen on autopsy?

THOMAS: Not that Dr. Baker described, and not that I saw, no.

BLACKWELL: In fact, his heart was so ordinary in terms of non-injury that it wasn't even photographed intact, was it?

THOMAS: Not intact, no. Dr. Baker took one photo that showed no scars and no acute injury.

BLACKWELL: Now, you were asked about certain studies out of Canada.


BLACKWELL: On the prone position.


BLACKWELL: And now -- and the findings out of Canada supposedly with real police and real police settings was no fatalities?


BLACKWELL: Are you familiar with any such studies reaching that conclusion in the United States of America?


BLACKWELL: What is so peculiar then about Canada that we're talking about Canadian studies here?

THOMAS: That's what I don't understand. I don't -- I mean, yes, I found that study, and I just thought, I don't know how to interpret this because it just -- it's so contrary to the actual experience of forensic pathologists in the United States.


BLACKWELL: Now, you were asked questions about whether the prone position is safe to lay on your stomach.


BLACKWELL: Are you familiar with whether or not laying in the prone position automatically brings about a reduction in the oxygen reserves somewhere in the neighborhood of 20 percent to 24 percent?

THOMAS: I am not aware of that, but I would defer to a clinician.

BLACKWELL: Perhaps a pulmonologist?

THOMAS: That would be the best, yes.

BLACKWELL: I think you were, in fact, asked a question about laying by the pool on my stomach in Florida.


BLACKWELL: George Floyd was not laying by the pool on his stomach in Florida, was he?


BLACKWELL: I know the answer to this but I'll ask you. You were asked a question about sitting on a church bench with a baseball under your butt. You've never done that?


BLACKWELL: Now, you were asked questions about symptoms of damage to the brain.


BLACKWELL: And whether there was any evidence of damage to Mr. Floyd's brain?


BLACKWELL: Would you tell the ladies and gentlemen of the jury whether the fact that you observed an anoxic seizure in Mr. Floyd, was that evidence of damage to the brain?

THOMAS: So, yes. What happens in the brain is when there's inadequate oxygen, it reacts by causing this anoxic reaction or seizure that we've described. If someone then goes on and essentially is brain dead but their heart can be restarted and they're kept alive for, say, a day, and then they die, then you will see changes in the brain.

But in a case like Mr. Floyd, where he died during this period of time and his heart was never able to be restarted, that is not enough time for the brain cells to show any kind of reaction that you could see at autopsy. BLACKWELL: Thank you, Dr. Thomas, no further questions.

CAHILL: Anything further?

NELSON: Yes, sir.

Dr. Thomas, after the heart stops, if the heart stops, is it possible that the body will continue to breathe, or respire?

THOMAS: Yes, I suppose it could, in some circumstances.

NELSON: And that could -- that continued respiration after the heart stops could be a matter of a minute or two, correct?

THOMAS: I suppose that could happen.

NELSON: And you would agree that methamphetamine also further constricts the arteries, right?

THOMAS: It can do that.

NELSON: And so that constriction, there's been a lot of discussion about the level of methamphetamine in the system, this low level, as it's been described, right? You said there's no safe level, agreed?


NELSON: Would you, as a physician, prescribe methamphetamine to a person who has a 90 percent or a 75 percent occlusion in the heart?

BLACKWELL: Objection, beyond the scope and irrelevant.

CAHILL: You may answer if you have an opinion in that regard.

THOMAS: Yes, I don't have an opinion, I'm sorry.

NELSON: Okay, no further questions.

CAHILL: Thank you, Dr. Thomas, you're excused.

Members of the jury, we'll take our lunch recess, we'll reconvene at 1:30.

ERICA HILL, CNN NEWSROOM: Dr. Lindsey Thomas, after spending a significant portion of her morning on the stand there with a grateful thanks to the judge as he told her it was time to break for lunch, and that she was done as a witness.

Let's bring in now Laura Coates, Charles Ramsey and forensic pathologist Dr. Christopher happy.

This was yet another morning where I found myself glued to my television as I was learning so much about what a forensic pathologist does, how an autopsy is performed, what that initial autopsy report that we often see, what it really tells us and what else goes into making determinations on manner and cause of death. We're going to get to all of that.


But, Laura, I think we need to pick up with where we just left off here at the end.

So we saw from the defense some really interesting lines of questioning, I would say, basically saying to Dr. Thomas, so if you took everything out of this equation and Mr. Floyd had been found at home, would you have another cause of death? On the prosecution, the attorney, Mr. Blackwell, picked up on that pretty quickly and asked her about it. I want to play that quickly. It's SAT 7 (ph).


BLACKWELL: Dr. Thomas, from your standpoint as a forensic pathologist and your analysis of manner and cause of death, would you ever approach an assessment of manner and cause of death by taking out of it the facts that you found relevant and highly pertinent to assessing and determining the manner and cause of death?


BLACKWELL: And in this case those factors are what?

THOMAS: The law enforcement subdual, restraint and compression.


HILL: Laura, that's a pretty remarkable moment. Have you ever seen something like that before?

LAURA COATES, CNN SENIOR LEGAL ANALYST: You know, it was so odd because here is why both prosecutors, but especially defense, have got to be very wary about using hypotheticals. Because it comes across to the jury that they're trying to be cute or they're being disingenuous or they just don't get what we're talking about.

The idea of that old phrase, walks like a duck and talks like a duck. Well, look, if it's a hypothetical that has nothing to do with the facts in this case, it invites the prosecution to do exactly what he did, which is to revisit what actually happened here.

And he tried to initially say a phrase that, frankly, my father has said all of my life, which was, hey, but for the incident at the theater, Mrs. Lincoln, how was your evening? And it points out this notion of, you're trying to distill this down in such a reductive way that you're losing all of the facts that are at issue in this case.

So every time this defense counsel tries to raise hypotheticals that have nothing to do with these facts, he invites a new witness, not a fact witness, but an expert witness, to now revisit and remind the jury of what happened to George Floyd in his final moments. It's dangerous.

HILL: Dr. Happy, as we're walking through all of this with Dr. Thomas this morning, she also talked about how there's so much more than just this autopsy from Dr. Baker that she relied on, that there was such a volume of material in this particular case. I want to play that moment as well because I'm just curious of your take on it.


THOMAS: What was absolutely unique in this case was the volume of materials I had to review. I've never had a case like this that had such thorough documentation of the terminal events.

In this case, the autopsy itself didn't tell me the cause and manner of death and it really required getting all of this other additional information, specifically the video evidence of the terminal events to conclude the cause of death.


HILL: Dr. Happy, we've talked a lot throughout this case about this trove of evidence, specifically of video evidence from nearly every angle. How does -- give us a sense of why she's able to paint such a more specific picture of what happened? How does this change of things for you in your line of work to have that information?

DR. CHRISTOPHER HAPPY, BOARD-CERTIFIED FORENSIC PATHOLOGIST: Yes. Well, of course, in vast majority of cases, we don't have a lot of video evidence of the terminal event. So, Mr. Floyd's case is unique in that respect. We have all these different angles. We have the bystander video. We have the police body cam video. So we're able to get an exact idea of what was going on, what the restraint was, what the subdual was and what the neck compression was just before Mr. Floyd died. That's unusual. We don't usually have that.

So, of course, that's other evidence that is beside what we can see at autopsy. And in the case of Mr. Floyd, we don't see a lot at autopsy because his death occurred -- you know, they're making it sound like it's a very long time but, you know, it's ten minutes.

So there's not a lot of changes that are going to happen in the body. You know, the heart muscle doesn't start breaking down and showing that it's broken down until an hour or two after a heart attack. We don't see anything like that. The brain cells don't show destruction until about eight hours after an anoxic event, meaning an event where there's no oxygen or blood flowing to the brain.


So that's why we have this autopsy not showing injury, because it doesn't take a lot of weight to close your carotid artery, so you don't have to, you know, impact at site. You might not get a bruise. You might not even get an abrasion on your neck but you can collapse the artery, you can collapse the veins in the neck and that will restrict the blood flow to the brain.

HILL: And just to follow-up on that real quickly, is there anything you heard from Dr. Thomas today, Dr. Happy, that was surprising to you in terms of either her methodology or her findings? HAPPY: No, I don't think so. I mean, this is how we do it. This is very likely the same sort of series of events that Dr. Baker went through after he performed the autopsy, and got all his findings, got the toxicology findings back, noted all his findings in the autopsy report. Then he looked at the other evidence. He looked at all of the video evidence. He probably read the police reports. He read -- perhaps even he had witness statements that he took into consideration.

All those things were very important in Mr. Floyd's case because we don't see a lot of injury at the time of the autopsy or in the tissues. And that's because this is a functional problem with Mr. Floyd. It was the blood flow going to his brain that was stopped. We can't see that after autopsy, as you -- obviously because there's no more function after you die.

HILL: This is all leading up to the medical examiner, as we know, Commissioner. I'm just curious your take, as you're watching all of this unfold, especially based on your career in law enforcement, how -- how is it playing out in your mind right now?

CHARLES RAMSEY, CNN LAW ENFORCEMENT ANALYST: Well, I mean, we're in a very technical part of this. In my mind, from my background in policing, I'm still looking at this in a very simple way, and that is the officers responded to an individual who's allegedly tried to pass a counterfeit $20 bill. They handcuffed him, they tried to get him in the car, he refused. They pulled him through the car. They got him in a prone position while he was already handcuffed, used their body weight for more than nine minutes, and well beyond what was necessary. It was beyond their policy of that department, beyond their training.

And I find it hard to believe that if it weren't for the actions of the police officers at approximately 8:30 at night on May 25th, 2020, Mr. Floyd would have died. Their actions, in my opinion, were a substantial reason why that man died. That's it.

And so I know all this other has to go on. I understand all that. But the bottom line is, their actions led to his death, in my opinion. And so all this other stuff, and, of course, the defense is going to throw as much as they can, his heart, his lungs, his this, his that, the odds of him dropping dead at that precise moment in time if the police were never there, in my opinion, just -- it just wouldn't have happened.

HILL: Laura, as we're building up to Dr. Baker, the medical examiner, there was a lot of talk that the witnesses that we've heard from thus far, specifically yesterday, Dr. Tobin, and even today, Dr. Thomas, that maybe this was sort of a prebuttal. But it's not coming across that way at all. In fact, it feels to me like that they're really setting up here is how we got to the point with this autopsy, everything else that goes into it, and we don't feel the need for a prebuttal. Am I following that correctly, Laura?

COATES: I think you are, indeed, Erica, and here is why. This is now complimentary testimony. You build off -- of course, last year, when Mr. Floyd died, there was the family of George Floyd who also ordered a separate review and autopsy as well. So it had in people's mind the thought that whatever the medical examiner from Hennepin County was issued was somehow controversial and would be at odds with what the family actually said.

But remember here, these reports aren't written to be the headline on the front page of a paper or some sort of fictionalized text that you enjoy reading. These medical reports are intended for medical purposes. They're often very technical. There's not a lot of color as a part of it. And so what they're trying to do is give that context.

So, if somebody makes a very reductive, seemingly dismissive of the facts at hand statement about cardiopulmonary arrest, it suggests to laymen that, oh, are you saying he had a heart attack and it wasn't the officer's behavior? These witnesses have laid the foundation to help you understand that, no, when the person writes cardiopulmonary arrest, here is what that means, here is what their colleagues would interpret it to mean, here is what it doesn't mean and here is what it does not say did not happened.


And, in fact, a powerful moment was the forensic.