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5:20 p.m. Court in recess until Friday morning

Attorneys concluded their questioning of Dr. Bill Smock in the trial of Derek Chauvin shortly after 5 p.m. Thursday.

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The Louisville Metro Police Department surgeon's testimony is likely to strengthen the prosecution's argument that George Floyd died primarily from oxygen deprivation and not because of his drug use or underlying health conditions, both of which Smock downplayed the significance of.

Court is expected to resume Friday morning, April 9 at 9:15 a.m.

4:55 p.m. Surgeon also attributes Floyd's death to asphyxiation

Dr. Bill Smock testified as an expert witness for prosecutors in the case of Derek Chauvin Thursday that George Floyd died of "positional asphyxia."

"Which is a fancy way to say that he died because he had no oxygen in his body," the Louisville Metro Police Department surgeon said.

Smock is the latest witness to testify in court to the role that the weight Floyd's arresting officers exerted on him the night of May 25 played in his death. He dismissed the idea that fentanyl, which Floyd was found to have consumed at some point before he died, caused him to fatally overdose.

Floyd seemed in footage of his arrest to be alert and responding to the pain of being restrained, according to Smock.

"He's breathing. He's talking. He's not snoring. He's saying, 'please, please get off of me, I can’t breathe.' That is not a fentanyl overdose. That's someone begging to breathe," he said.

The idea that Floyd experienced "excited delirium" at the time of his arrest he also does not align with indicators gleaned from footage of his last moments, according to Smock. He was not behaving in an agitated manner, was not sweating profusely and was not breathing rapidly, Smock said for example.

4:20 p.m. Toxicologist concludes testimony as new forensic expert takes stand

Before concluding his testimony Thursday, Dr. Daniel Isenschmid told jurors that the amount of methamphetamine that the lab he works for found in George Floyd's blood and urine would not have been sufficient to cause intoxication.

That was shortly after he told jurors that levels of the drug and of fentanyl found in Floyd's body after his death were low compared to mean levels of the two that were observed in a sampling of other DUI and fatal fentanyl case analyses the lab performed. Isenschmid also confirmed to the attorney for Derek Chauvin that the fatalities sampled were not themselves necessarily caused by fentanyl, but involved dead individuals in whose bodies the opioid was found.

After he was dismissed, Dr. Bill Smock, a surgeon for the metropolitan police department in Louisville, Ky. was called to testify. He is expected to be the last witness called Thursday.

3:50 p.m. Toxicologist discusses analyses of Floyd's blood, urine samples

Dr. Daniel Isenschmid of Horsham, Pa.-based NMS Labs in his testimony to state prosecutors Thursday afternoon called into question the role that drugs played in George Floyd's death.

According to Isenschmid, NMS Labs analyzed the contents of Floyd's blood and urine and observed in them low levels of methamphetamine and fentanyl, both of which an autopsy found he consumed, compared to mean levels of the drugs identified in a sampling of other DUI and fentanyl fatality analyses that the lab performed.

In this still image from video, Dr. Daniel Isenschmid of Horsham, Pa.-based NMS Labs testifies in the trial of Derek Chauvin on Thursday, April 8. (Forum News Service.)
In this still image from video, Dr. Daniel Isenschmid of Horsham, Pa.-based NMS Labs testifies in the trial of Derek Chauvin on Thursday, April 8. (Forum News Service.)


2:35 p.m.: Chicago doctor concludes testimony

Dr. Martin Tobin reaffirmed late Thursday afternoon his belief that George Floyd's death was the result of low oxygen levels.

Tobin told the defense that Floyd’s underlying heart conditions did not seem to affect his ability to breathe the night he died last May. If it had, according to Tobin, he would likely have been breathing more rapidly, which he did not appear to be doing in footage from that evening.

Asked by state prosecutor Jerry Blackwell if any of Floyd's medical conditions had "anything to do with the cause his death in your professional opinion whatsoever," Tobin replied: "None whatsoever."

Tobin also confirmed for the defense that Floyd's autopsy did not show bruising of his neck or hypopharynx, which is part of the human throat. That followed his testimony earlier Thursday that Derek Chauvin hindered Floyd's breathing by kneeling on his neck and back.

Tobin told the prosecution afterward, however, that he would not have expected such signs of injury to appear in an autopsy, and that force needed to cause them was "totally different" from the force required to restrict another's breathing. He also said that there was no evidence of meth and fentanyl, which were found in Floyd's system after his death, having contributed to Floyd's death.

After Tobin concluded his testimony, Dr. Daniel Isenschmid, a forensic toxicologist from Pennsylvania, was called as a witness.

1:50 p.m.: Court resumes with expert witness under cross-examination

The trial of Derek Chauvin resumed Thursday afternoon with Dr. Martin Tobin returning to the witness stand, where he is being questioned by the ex-officer's defense attorney.

Noon: Doctor testifies Floyd stopped breathing before Chauvin stopped kneeling on him

Based on his review of footage and documentation of George Floyd's arrest and eventual death, pulmonologist Dr. Martin Tobin testified that Derek Chauvin continued kneeling on Floyd's neck for roughly 3 minutes after Floyd stopped breathing.

"At that point, there's not an ounce of oxygen left in his body,Tobin said, referring to a still image from video that was shown in court Thursday of Floyd being restrained.

Testifying as an outside expert for state prosecutors, Tobin said that Floyd's breathing rate in earlier segments of footage was comparable to that of any other healthy individual of his age and weight. Fentanyl, an opioid that Floyd's autopsy found he had consumed, did not appear to depress his breathing rate in a manner consistent with the drug, Tobin said.

The pulmonary and critical care doctor's words appear to contradict the argument of Chauvin's defense team, which has sought to emphasize the role that drug use and underlying health conditions played in Floyd's death.

Chauvin's defense attorney is expected to question Tobin when court resumes at 1:30 p.m.

This still image from video shows a mock-up of what Chicago-area pulmonologist Dr. Martin Tobin described as the force the ex-officer exerted on George Floyd in the moments before he died May 25, 2020. (Forum News Service)
This still image from video shows a mock-up of what Chicago-area pulmonologist Dr. Martin Tobin described as the force the ex-officer exerted on George Floyd in the moments before he died May 25, 2020. (Forum News Service)


11:30 a.m.: Doctor's models suggest Floyd's lung functions were hindered during restraint

Laying in a prone position as George Floyd did before he died would have reduced his lung function by approximately 24%, a Chicago-area doctor testifying in the case against Derek Chauvin said this morning.

Combine that with force that Chauvin, himself weighed down with gear, exerted on Floyd by kneeling on his neck and back, according to Dr. Martin Tobin, and Floyd's lung function would have dropped by a total of around 43%. Tobin detailed those calculations to jurors after describing the anatomical process of breathing on Thursday.

Tobin said earlier this morning that Floyd died the night of May 25, 2020 of "low oxygen" levels resulting from shallow breathing, which itself was caused by him being handcuffed prone on the ground with weight being applied to his neck and back.

10:25 a.m.: Floyd was in a 'vise,' doctor says

The weight that ex-officer Derek Chauvin and his colleagues exerted on George Floyd as he lie prone on the ground the night of May 25, 2020, combined with the pressure of the street itself, trapped Floyd in a "vise" of sorts that prevented him from drawing breath, according to a Chicago-area doctor testifying in Chauvin's trial.

"He was being squashed in between the two sides," Dr. Martin Tobin told the prosecution Thursday morning.

Pressing Floyd's hands, which were cuffed behind him at the time, into his back added to the pressure he was under. Asked by the prosecution to explain the significance of Chauvin kneeling on Floyd's neck in particular, the doctor said the ex-officer's knee would "occlude" the airway.

That Floyd could be seen at one point in footage from his arrest pressing the knuckles of a cuffed hand onto the ground, Tobin said, suggests he was trying to lift himself somewhat so as to breathe more easily.

9:50 a.m.: Doctor weighs in on cause of George Floyd's death

A Loyola University professor and doctor testifying in the trial of Derek Chauvin said Thursday morning that George Floyd died "from a low level of oxygen" that damaged his brain and heart.

Dr. Martin Tobin told prosecutors from the witness stand that Floyd's low oxygen levels were the result of protracted shallow breathing, which itself was caused by his being handcuffed in a prone position with body weight being applied to his back and neck.

"He is virtually on (Floyd's) neck for the vast majority of time," Tobin said of Chauvin.

Tobin said he has testified in court before, primarily in malpractice cases. The state of Minnesota reached out to him but is not paying for his appearance in Chauvin's trial, he said, and he believes he has "some knowledge that would be helpful to explain how Mr. Floyd died."

He has reviewed materials related to the circumstances of Floyd's death.

9:30 a.m.: Medical expert testimonies expected Thursday

Medical experts are expected to testify Thursday, April 8, in the trial of Derek Chauvin. State prosecutors have signaled that they will tomorrow call Dr. Andrew Baker, of the medical examiner for Hennepin County, who performed George Floyd's autopsy, as a witness.

Dr. Martin Tobin was first to take the stand Thursday. The Loyola University Medical Center of Maywood, Ill., professor is an expert on critical care and pulmonary medicine, the latter of which relates to the lungs.

In this still image from a web broadcast, Dr. Martin Tobin of the Loyola University Medical Center in Maywood, Ill., testifies Thursday, April 8 in the trial of Derek Chauvin. (Forum News Service.)
In this still image from a web broadcast, Dr. Martin Tobin of the Loyola University Medical Center in Maywood, Ill., testifies Thursday, April 8 in the trial of Derek Chauvin. (Forum News Service.)

9 a.m.: Wednesday testimony focused on forensics

Court is scheduled to resume this morning at 9:15 a.m., a day after jurors in the trial of Derek Chauvin heard Wednesday from forensic scientists who took part in the investigation of the case.

Pills recovered from the scene of George Floyd's arrest, they testified, tested positive for methamphetamine and fentanyl, both of which were found in Floyd's system after an autopsy. Chauvin's defense attorney, Eric Nelson, has sought to emphasize the role that drugs played in Floyd's death over that of his client.

In this image from video, Sgt. Jody Stiger of the Los Angeles Police Department answers questions Wednesday, April 7, 2021, during the trial of former Minneapolis police officer Derek Chauvin for second-degree murder, third-degree murder and second-degree manslaughter in the death of George Floyd. (Pool via REUTERS)
In this image from video, Sgt. Jody Stiger of the Los Angeles Police Department answers questions Wednesday, April 7, 2021, during the trial of former Minneapolis police officer Derek Chauvin for second-degree murder, third-degree murder and second-degree manslaughter in the death of George Floyd. (Pool via REUTERS)

State prosecutors, meanwhile, collected testimony Wednesday, April 7 that bolstered their claims of Chauvin's use of force being excessive. Police Sgt. Jody Stiger, a Los Angeles Police Department official who testified as an expert in the case that day, said the ex-officer's actions amounted to deadly and excessive force given that Floyd offered no resistance after being laid prone upon the ground in handcuffs the night of May 25, 2020.