Return to Transcripts main page
Prosecution Questions Forensic Pathologist in Chauvin Trial. Aired 11-11:30a ET
Aired April 9, 2021 - 11:00 ET
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
DR. LINDSEY THOMAS, FORENSIC PATHOLOGIST: Muscles in between your ribs.
So when you've taken a deep breath, what's happening is your rib cage is expanding, and that then forces the lungs to open up and that's what draws air in.
So, if it's -- when someone is intubated in like is surgery or something, it's sort of the opposite of that, because your diaphragm is paralyzed. So, somebody has to force air in. But under normal breathing circumstances, you just -- it's the bellows, it's the pulling air in.
JERRY BLACKWELL, PROSECUTING ATTORNEY: So what did the video tell you? What did you see in it that had to do with the bellows function?
THOMAS: Right. Well, he -- Mr. Floyd is in a position -- so, first of all, he is prone or sort of slightly with his head to the side, and he has his arms handcuffed behind his back. So that's already a bit of a difficult position to be in, the prone and handcuffed.
And then with -- at times, at least three officers on top of him, whether it's his neck or back or his lower back or legs, it prevents him from moving his body into a position where he can adequately use the bellows function. And his chest is sort of compressed in this position in such a way that he can't adequately expand and get enough oxygen in.
BLACKWELL: Over what period of time was this?
THOMAS: Nine minutes.
BLACKWELL: So what did you see in those nine minutes that led you to conclude the mechanism of death was low oxygen or asphyxia?
THOMAS: Well, initially, he, Mr. Floyd, is able to struggle pretty vigorously in this position that he recognizes as it's going to be hard for him to breathe in this position.
PETER CAHILL, HENNEPIN COUNTY COURTHOUSE: Sustained. The last part of the answer about Mr. Floyd's state of mind is stricken as speculative.
So, initially when he is in the prone position, he's breathing and speaking, and it might look like oh, he's at that point getting enough air exchange. But over time, you can see that his breathing is getting more and more difficult and he is saying less and less.
And then about half way through, the whole restraint subdual compression process, he stops breathing. Well, he first stops speaking entirely. And then, again, shortly after that, there is a movement that I believe is what's called an anoxic brain reaction, which is -- it looks like kind of a twitch. It is something that the body does when the brain no longer has enough oxygen.
So that's the point at which you can tell by looking, oh, that's where he no longer is getting enough oxygen to his brain. And then the restraint and subdual and compression continue for many minutes more even after someone checks and says, oh, there is no pulse. They maintain had the position so at that point, his heart has also stopped. So, he stopped breathing and his heart stopped.
BLACKWELL: So, doctor, you mention an anoxic, A-N-O-X-I-C?
BLACKWELL: Anoxic brain reaction?
BLACKWELL: Is it also known as an anoxic seizure?
BLACKWELL: Is that something that a person did consciously and voluntarily?
THOMAS: Oh, no. No. It's something that your body just does when your brain doesn't have enough oxygen.
It's why in lots of cases people who are witnessing someone die will say they had a seizure and died. Well, no, what is actually happening is they've basically died. Their brain doesn't have enough oxygen and then they have this muscle twitch that may look like a seizure.
BLACKWELL: So can we go back to exhibit 193? I want to ask you about, that is in front of you if we can talk about that.
So do you see where I'm referring to the other contributing conditions?
BLACKWELL: And what are those? THOMAS: In this case, they are arterial and hypertensive heart
disease, fentanyl intoxication and recent methamphetamine use.
BLACKWELL: So, would you explain for the jury what does it mean other contributing conditions?
THOMAS: So the way forensic pathologists and medical examiners use this is people often think of the death certificate is for that person, that specific person who died and their family. And that's true. It does serve a very useful purpose for life insurance, whatever.
But forensic pathologists are also using death certificates for public health data purposes. And so, in any given case, we aren't just thinking about this particular person and their cause and manner of death. We're also thinking the state and federal government collect data on why do people die? What is cause of death?
It's how we know as a country we have, you know, how many people die of COVID-19, for example? Death certificates list that. So one of the things that we use this other contributing condition for is to list disease processes or drugs that are present at the time of death but that we don't directly -- that we don't believe directly contributed to the cause of death.
But it's so that someone looking at data years from now can say, okay, we want to do an evaluation of all deaths during law enforcement subdual. And how many of those deaths involve someone who also had drugs onboard? Because that may be something that is relevant than in trying to prevent these sort of deaths in the future, for example.
Or the case where I use the contributing conditions probably the most is the hip fracture case that I talked about before, where someone dies of a hip fracture due to a fall. But they're 84 years old and they also have hypertensive heart disease, arteriosclerotic heart disease, asthma, diabetes.
And so I will list those as other contributing conditions. Now in no way did those things cause the fall and the hip fracture and the resulting whatever pneumonia or whatever. But again, someone from a data perspective might want to know, you know, of the 84-year-old women who die of hip fractures, what percentage of them have underlying heart disease?
Because again, from a data collection standpoint, does that provide useful public health information that can be used in the future to try and prevent these deaths? So that's how I would view this. It's very long winded, sorry.
BLACKWELL: Sure. No, Dr. Thomas. So, in understanding this further, so other contributing conditions, are conditions that may have contributed but were not the direct cause of the death?
BLACKWELL: Did you consider these other contributing conditions in your assessment of the cause and mechanism of death for George Floyd?
BLACKWELL: And what -- how did you consider them, first of all?
THOMAS: Well, I wanted to look at each one and ask the question, is this the cause of his death? Is arteriosclerotic heart disease the cause of his death?
He has narrowing of his coronary arteries. In many cases, that is the cause of someone's death. So I looked at that.
But again, it comes down to, what were the history of the terminal events? Does this look like the type of death we see or is, you know, I'm not a clinician, so I don't see it. But as a forensic pathologist, I know from hundreds of families describing what happened at the time of death, that this death does not fit what has been described in someone who dies of a cardiac arrhythmia from arteriosclerotic heart disease.
And likewise, hypertensive heart disease. Those tend to be cardiac arrhythmias, sudden cardiac deaths, this is not that kind of death.
Likewise, fentanyl intoxication as I described, again, I don't treat patients, I don't see living people. But what I know from family members who describe deaths but then later turn out to be due to fentanyl, the death is slow.
It's peaceful. They fall asleep. They may here snoring or very heavy deep breathing.
There is no struggle. They just often are found just kind of slumped over. It's a very slow death. So again, totally different than what is seen in Mr. Floyd's death.
Methamphetamine as a cause of death generally is, again, much more of a sudden death. It may cause a cardiac arrhythmia. It may cause a seizure, I don't mean this sort of terminal anoxic twitch but like a full blown seizure and, again, looking from what I know about Mr. Floyd's death because it's so well-documented, that does not fit with a methamphetamine death.
BLACKWELL: So you reviewed the toxicology?
THOMAS: Yes, oh, yes.
BLACKWELL: How would you characterize the amount of meth in Mr. Floyd's system at the time?
THOMAS: Well, it was there. It's not particularly high. Certainly in deaths that I have attributed to methamphetamine, it's much higher. But it's not like there is any safe level of methamphetamine. But this was a very low level.
BLACKWELL: So was the meth significant in your estimate as the cause of death?
BLACKWELL: So then based on your review of the video and application of the experience and knowledge, did you rule out drug overdose as a cause of death?
BLACKWELL: And that's an opinion you hold to reasonable degree of medical certainty?
BLACKWELL: Now I want to clarify this early and just forgot to. Does the medical examiner also complete the death certificate?
THOMAS: Yes. We don't issue it. That comes from the county or state. But as a medical examiner, we fill out all of the cause and manner and how injury occurred and all that kind of stuff.
BLACKWELL: How many death certificates have you filled out?
THOMAS: Oh, gosh, well, thousands and thousands.
BLACKWELL: So if we look here, again, at the exhibit in front of you, 193, in the left margin, we see a reference here to underlying.
BLACKWELL: Would you tell the jurors what that means?
THOMAS: Sure. So let's go back to that hip fracture. I keep referring to that. But, for example, someone who dies of a hip fracture generally that's not a sudden death. What happens is someone gets a hip fracture, they get it surgically repaired. They may get pneumonia or something like that.
So then in that kind of case, we list immediate cause of death as pneumonia. The underlying cause of that is the hip fracture that was operated. But the underlying cause of the hip fracture was the fall. They fell, they got a hip fracture, they got pneumonia. So it is something that is used when you have a death that has maybe multiple sequences of events.
But in a case like this, you don't need an underlying because it's all included in the first line. It's all due to the law enforcement subdual restraint and neck compression.
BLACKWELL: Now the death certificate does not use the word asphyxia or any reference to low oxygen.
BLACKWELL: Would you have used the word asphyxia in this case? THOMAS: Probably not. I tend not to use the word asphyxia much
because it requires a lot of explanation. It doesn't really offer much additional information unless you have a chance to have a discussion like we've had about what asphyxia means.
So I tend to just list, you know, if someone dies of hanging, well that's a type of asphyxial death. But I wouldn't say necessarily asphyxia due to hanging. I would just list hanging as the cause of death.
BLACKWELL: So to refer to asphyxia or low oxygen, doesn't tell you anything about why there is asphyxia or low oxygen?
BLACKWELL: Are the findings on autopsy that suggest low oxygen as a cause of death?
THOMAS: No. There is nothing on autopsy that shows low oxygen.
BLACKWELL: There is no test that can be done for low oxygen on autopsy?
BLACKWELL: Are there physical findings that sometimes may be found and maybe consistent with low oxygen?
THOMAS: So there are no physical findings that show low oxygen.
But there may be physical findings that are consistent with a cause of death that may result in low oxygen. So, for example, the hanging. Let's use that, the hanging.
If someone is partially hanged, by that I mean they are only partially suspended. So there is some pressure on their neck, they may have what are called petechiae or little pinpoint hemorrhages in the eyes, because blood is still going into their head but not able to drain out because of the pressure on the neck. So at autopsy, we will see the petechiae eye and we can say based on the scene investigation and the history that finding is consistent with hanging which the mechanism for hanging is a type of asphyxia.
Or in manual strangulation, we might see bruising or we might see broken bones in the neck. And the mechanism of death in strangulation is low oxygen, but the finding that we are seeing is consistent with strangulation.
So it's kind of a fine line between saying it's not the low oxygen that we see at autopsy but sometimes, not always, but sometimes in cases where the death is the result of low oxygen, we see specific findings related to the cause.
BLACKWELL: So if you then see petechiae, it could help to lead you to the conclusion that it was death by low oxygen.
BLACKWELL: But if you don't see petechiae, what can you conclude?
THOMAS: Nothing. So it's one of those things that when it's present, if there's the broken bones in the neck or bruising, that is very helpful in putting together a picture of what might have happened. But if you don't have them, it doesn't help you one way or the other.
BLACKWELL: And by not help you one way or the other, that means you can't conclude from that alone that a person did or did not die of low oxygen?
BLACKWELL: And you mentioned bruising in that context.
THOMAS: Right. And again, sometimes, I mean, for example, strangulation is a great example. Sometimes in strangulation, you have all kind of bruises that you can see on the neck. But other times, there is a strangulation case and they don't have a single mark on their neck.
And -- I mean, there's all kinds of reasons that bruises may or may not occur. But it's again one of those thing it's there, it's very helpful. If it's not, it's not helpful.
BLACKWELL: Were there other findings in the death investigation that supported your conclusion on the cause or mechanism of George Floyd's death?
BLACKWELL: Would you tell us what those were?
THOMAS: So Mr. Floyd had had superficial injuries, what would be described as superficial injuries specifically on his face, on his shoulders, on his wrists. And what that does is it supports what I saw in the videos which is that he is being forcibly restrained and subdued and he's trying to move into a position by rubbing his face against the concrete cement of the ground, by pulling against his handcuffs. You can see the injury to his wrists from the handcuffs, and by pushing with his shoulder.
And he also had some scrapes on his knuckles on his right hand. Again that, is from him pushing to try to get into a position where he could breathe.
BLACKWELL: Dr. Thomas, are there photographs that depict what you're describing?
THOMAS: Oh, yes, thank you.
BLACKWELL: Your Honor, we stipulated by way of foundation to the photos we have individual packets for the jurors. CAHILL: Members of the jury, there is some stipulated photographs
that are going to be shown to you. Or as we call, as you heard me say, publish to you.
We're going to go old school this time. We're not going to put everything on the monitors. We're not going to broadcast it out. But everybody in the courtroom will have access to it, including yourselves, essentially a packet with these photographs.
We'll collect them afterwards. These are for you to use in the courtroom. The actual exhibit will be available in deliberation, however.
BLACKWELL: Would you like the deputy or someone to distribute these or should I?
CAHILL: You can go ahead, Mr. Blackwell.
CAHILL: Before you can look through them, you can take them out but don't start looking through them until Mr. Blackwell resumes his examination.
Mr. Blackwell, Mr. Schleicher will take care of the rest.
Hold on Mr. Blackwell. We'll make sure everyone who gets a copy gets one.
Spectators can each get a copy if they want one.
You have to give up one of your copies. There you go.
BLACKWELL: Your Honor, if I may, I think I'll give one to Dr. Thomas so she has one.
CAHILL: She can have mine.
THOMAS: Oh, thank you.
BLACKWELL: And, Your Honor, we'll have the camera off.
So, Dr. Thomas, if we start with the exhibit that is marked 185 --
BLACKWELL: I take that back. I would like to see it on my screen.
Dr. Thomas, looking at exhibit 185, what is significant in this photograph that informs your conclusions pertaining to the restraint and subdual as a cause of Mr. Floyd's death?
THOMAS: This is a photograph of Mr. Floyd's face. And it shows some facial injuries, most notably the -- what are called abrasions which are scrapes over his left eyebrow and over his left cheek. You can also see there is littler scrapes or small cuts on his nose and lip, upper lip and a little on the left side of the lower lip.
But the main thing this shows is that the left side of his face was obviously in contact with some rough surface.
BLACKWELL: Dr. Thomas, if we look at exhibit 235, it may be a close- up of the same close-up of the same area.
THOMAS: Sir, there we go. Yes. That is a close-up of the left cheek and the left forehead. And, you can see, for example, above the left eyebrow, there's a dark area that's a dried scrape. As well as there say little bit of discoloration of the skin so that also there was a bruise there.
And then, on his left cheek, you can see the dark area as well as kind of a lighter orange pink area, and those are, again, scrapes. The dark area is where a scrape has dried.
BLACKWELL: What does it tell you about the cause or mechanism of the death?
THOMAS: It's consistent with the impression from watching the video that his face was on the ground and he was moving his face in an effort to get into a position where he could breathe.
BLACKWELL: Let's look at exhibit 188.
THOMAS: This is a photograph of Mr. Floyd's left shoulder.
BLACKWELL: And what do we see here?
THOMAS: This again is an area of scrapes and indicates that there was some force between his shoulder and some rough surface in this case the ground. And again is consistent with what it looks like on the video that he's struggling to push himself into a position where he can breathe.
BLACKWELL: Let's look at exhibit 187.
THOMAS: This is a photograph of his right shoulder. Again, you can see there's a little bit of discoloration and then the skin is scraped. So there is less injury impact here and that fits with, again, what you see in the video, of which side was down and which side had more contact with the ground?
BLACKWELL: Let's look at exhibit 189.
THOMAS: This is a photograph of Mr. Floyd's left hand. And if you look at the base of his hand, sort of right over his wrist, you can see there is some areas of red discoloration with kind of a pale area in between. And that's consistent with handcuff marks. You can also see on the sort of outer edge, there's some white material that is dried skin. And that's an area where his skin has actually been rubbed up from the handcuffs.
BLACKWELL: And, Doctor, exhibit 190?
THOMAS: Exhibit 190 is a photograph of his right hand and wrist. And, again, in this case, you can see more clearly the sort of double lined discoloration above his right wrist that's consistent with the handcuff marks. And indicates pressure against handcuffs.
And, again, on the outer edge, you can see there is a little bit where it's darker and then there is some white skin. So, that's an area where it's actually been scraped, the skin has actually been scraped by the handcuffs.
Also, on this photograph, you can see on the knuckles of his index finger and middle finger, there's some skin that is scraped off. And that's consistent with what you can see on the video where he's pushing against, I think it's the rim of the car tire or something, to try and push his body into a position again where he can breathe.
BLACKWELL: Thank you, Dr. Thomas.
Your honor, the jurors may put the photographs away if they'd like.
CAHILL: They're simply for your use during this time.
We ask spectators also to return the exhibits. Thank you.
BLACKWELL: Thank you, Your Honor. So Dr. Thomas, having looked at this physical evidence from the autopsy, was that evidence in of and by itself conclusive?
THOMAS: No. There are multiple ways that scrapes and bruises can happen. It's only useful in the context of what is seen in the videos.
BLACKWELL: Was there any evidence to suggest that Mr. Floyd was suffering from a potentially fatal condition on the evening of May 25th, 2020?
BLACKWELL: Do you have an opinion to reasonable degree of medical certainty if Mr. Floyd would have died that night had he not been subject to.