The GOAT Expert Witness: Dr. Martin Tobin

State of Minnesota v. Derek Chauvin (2021)

George Floyd

Background. Derek Chauvin, a former Minneapolis police officer, was one of four officers charged with murder in the death of George Floyd. On May 25, 2020, Chauvin was acting as a field training officer when he physically detained Mr. Floyd - who was suspected of using a counterfeit $20 bill - in broad daylight outside a convenience store. After Mr. Floyd was handcuffed and lying in a prone position on the asphalt, Chauvin placed his knee - along with the full weight of his body and gear - on Mr. Floyd's neck and upper body for 9 minutes and 29 seconds, killing him. The entire incident was captured on cell phone video, many taken by minors.

Charges. Several days after Mr. Floyd was killed, Derek Chauvin was arrested and charged with murder. The most serious charge listed in the indictment was Second Degree Unintentional Murder under Minn. Code Section 609.19, which states that a person is guilty of the offense when he "causes the death of a human being, without intent to effect the death of any person, while committing or attempting to commit a felony offense . . . ." It carries a maximum sentence of 40 years in prison.

The Trial. Jury selection for Chauvin's trial (the four officers were tried separately) began on March 8, 2021, in the Fourth Judicial District Court of Minnesota, before the Honorable Peter Cahill. State Attorney General Keith Ellison led the prosecution team and Eric Nelson represented the Defendant. The prosecution called 38 witnesses over eleven days. The defense called seven witnesses over two days. Dr. Martin Tobin testified as an expert in the State's case-in-chief and as a rebuttal witness, following close of defense proof. The central issues in the case concerned 1) the "use of force" justification defense, which allows law enforcement officers to use reasonable force necessary to effectuate a legal arrest, and 2) causation, i.e., whether the pressure that Chauvin and his fellow officers exerted onto Mr. Floyd's body actually caused his death. 

The Witness - Dr. Martin Tobin. The testimony of Dr. Tobin, an expert in pulmonary and critical care medicine, was absolutely crucial to the State's case as it established that the Defendant actually caused the death of Mr. Floyd. The defense claimed that other factors contributed to Mr. Floyd's death, including alleged drug use, existing health problems, and carbon monoxide poisoning. Special Prosecutor Jerry W. Blackwell, who is now a federal judge, conducted the direct examination of Dr. Tobin on April 8, 2021. Blackwell, who worked on the case pro bono, was a veteran trial attorney with some 35 years of litigation experience (notably, his star witness exceeded him by over a decade as he was in his 46th year of practicing medicine at the time of the trial). Dr. Tobin also worked pro bono.

Verdict & Sentence. After deliberating for ten hours over the course of two days, the jury found the Defendant guilty as charged. Derek Chauvin was the first white police officer in the State of Minnesota convicted of murder for the death of a Black person. Following his conviction, the Defendant was sentenced to 22.5 years in prison. His conviction was affirmed on appeal. The Defendant later entered a guilty plea to federal civil rights offenses and was sentenced on those charges as well.

WARNING: Some of the images depicted in the video and testimony are graphic.

Highlights from Direct Examination

• Dr. Tobin is sworn in at 48:15 (Law & Crime Network at 2:24)
• Qualifications - highlights:
• 52:00 - 53:30
• 55:55 - 58:30
• 59:00 - 59:30
• The Mayo Clinic Award
• Expert Opinion (1:04:25 - 1:06:28)
• Brief explanation of opinion (1:08:10 - 1:11:05)
• Breaking Down the Opinion
• How opinion relates to expertise (3:38-4:21)
• First factor: effect of handcuffs combined with street - "totally interfere with central features of how we breathe" (4:23 - 5:55) 
• 6:05 - explanation of how this interferes with breathing
• 6:52 - 8:55 - two actions that must happen to expand the chest - pump handle and bucket handle movements
• 8:20: "You can feel it yourself"

Video 1 - Highlights:

• Describing exhibit (0-0:50) 
• Knee on neck (1:19-45) 
• Brain and knee placement (2:15-3:03) 
• Handcuff demo (4:21-5:27) 
• Bucket handle (7:19-8:55) 
• Almost like removal (10:15-10:30) 
• Toe of Boot (stop at 5:00) 

Video 2 - Highlights:

• Fentanyl (0:00-1:29) 
• Last effort to breathe (4:15-4:30) 

Rebuttal - Direct Examination

• Brief re-introduction
• Are there studies as to whether pressure on the neck narrows the hypopharynx? (Explanation of lack of studies; ends w explanation of pressure on your neck to narrow airway – 10:40 - 11:25)