Medical examiner who did autopsy on Floyd expected on stand today

The Hennepin County medical examiner is expected to testify Friday in the Derek Chauvin murder trial, outlining his conclusions about what killed George Floyd that appear to be at odds with the findings of an earlier expert witness for the state.

Dr. Andrew Baker, who performed the only autopsy on Floyd after he died under the knee of a since-fired Minneapolis police officer on May 25, ruled the cause of death as "cardiopulmonary arrest complicating law enforcement subdual, restraint, and neck compression."

He also listed hardening and thickening of the artery walls, heart disease and illicit drug use as "other significant conditions." Fentanyl and methamphetamine were also found in Floyd's system.

Baker's expected testimony Friday could pose challenges for both the state and defense if it echoes the information exchanged in at least a half-dozen meetings he had with prosecutors leading up to the trial.

Documents obtained by the Star Tribune show Baker expressed skepticism that placing Floyd face down on the street with three officers on top of him would be "any more dangerous than other positions."

Cause of death has provided a sharp divide between the state and the defense. Defense attorney Eric Nelson has argued that Floyd died of a cardiac arrest, illicit drug use and various chronic health problems. A prosecution witness called Thursday concluded that Floyd died from a lack of oxygen while being held stomach-down and handcuffed on the pavement for more than 9 minutes.

Dr. Martin Tobin, a leading lung expert who has written textbooks and specialized in respiratory and critical care medicine for decades, said the oxygen that Floyd begged for minute after minute "caused damage to his brain that we see, and it also caused a [pulseless electrical activity] arrhythmia that caused his heart to stop."

The heavy dose of expert medical testimony filled the day Thursday. The end of a second week of testimony is scheduled to resume about 9:15 a.m. Friday.

Chauvin is on trial for second-degree murder, third-degree murder and manslaughter. The three other fired officers — J. Alexander Kueng, Thomas Lane and Tou Thao — are scheduled for trial in August on charges of aiding and abetting him. Thao held off the bystanders while the others restrained Floyd.

Tobin said his extensive review of the viral bystander video, footage from officers' body-worn cameras and on-the-street surveillance and investigative evidence led him to this conclusion:

Chauvin kept his knee on Floyd's neck for three minutes and 27 seconds after Floyd took his final breath.

In his cross-examinations, Nelson worked to show that Floyd could have died from a heart attack or overdose caused by drugs and underlying health problems, including arterial blockages. When prosecutor Jerry Blackwell asked Tobin whether Floyd's pre-existing health conditions had anything to do with his death, the doctor replied, "none whatsoever."

As the slowed-down bystander video was shown of Floyd's face, Tobin described the death: "You can see slight flickering and then it disappears, so one second he's alive and one second he's no longer. That's the moment the life goes out of his body."

A follow-up witness supported much of what Tobin said. Dr. Bill Smock, the police surgeon of the Louisville Police Department, also concluded that Floyd died from a lack of oxygen and not a fentanyl overdose. Smock said people who overdose on fentanyl become sleepy, snore, have constricted pupils and their breathing rate falls. With Floyd, Smock said, "that is not a fentanyl overdose. That is someone begging to breathe."

Star Tribune staff writers Rochelle Olson, Libor Jany and Chao Xiong contributed to this report.

Paul Walsh • 612-673-4482