Justin Feldman is an assistant professor of epidemiology at the New York University School of Medicine.

There is a clear takeaway from the video of George Floyd dying while Officer Derek Chauvin’s knee is pressed into his neck: Floyd was suffocated by the Minneapolis police officer. So how is it possible that preliminary findings from the Hennepin County Medical Examiner’s report emphasized underlying health conditions and “potential intoxicants” while ruling out asphyxiation?

Floyd’s death is hardly the only case in which medical examiners have produced baffling findings after conducting autopsies of people who died while in police custody. This case is more proof that if we want police accountability, we need to make sure medical examiners can issue honest, independent reports on how people such as Floyd died.

If discrepancies between what seem like obvious causes of death and what actually shows up in autopsy reports or on death certificates seem shocking, they aren’t uncommon. I know, because I worked with a group of other epidemiologists to match police killings reported in the media to death certificate summaries we obtained from the Centers for Disease Control and Prevention. (Under the privacy agreement governing the release of those summaries, we cannot discuss individual cases in detail.) We found that coroners and medical examiners throughout the United States routinely report findings that minimize the responsibility of police.

Our study identified 71 people who died in police custody after they had been subject to a Taser shock, chokehold or other form of restraint; after being transported in a police vehicle; or after being denied water while in detention. Medical examiners and coroners determined that only 24 of those people lost their lives because force was applied to them. In some of these cases, investigators correctly assigned a diagnostic code specific to police-related injury. But in others, the coroners and medical examiners used diagnostic codes meant to indicate a homicide between civilians. Even if these discrepancies were errors rather than deceptions, the result was that fewer police-involved deaths showed up in mortality data.

And a majority of these deaths — 47 of the 71 — were attributed to causes such as accidental injury, respiratory disease or mental illness, rather than to the actions of police officers. In some cases, the cause of death was reported as “undetermined.” While I did not have access to the full medical-examiner reports for these deaths in custody, the results strongly suggest that the role of police actions in the deaths were also minimized.

The brief summary of the initial autopsy findings attributed Floyd’s death to a lethal, multifactorial combination of unconfirmed drug intoxication, underlying health conditions and police restraint.

That language is familiar to me. Many pathologists attribute deaths in police custody to a controversial condition called “excited delirium,” which they suggest arises from a drug-induced aggressive psychological state that leads to respiratory arrest and death. The diagnosis was proposed in 1985 specifically to explain a series of deaths in U.S. jails. Thirty-five years later, excited delirium is not a recognized medical diagnosis, and there is no clear explanation of what is supposed to be happening in the body of someone allegedly experiencing it. The ambiguity of excited delirium allows medical examiners a great deal of discretion when determining whether a particular death fits its profile.

These suspicious diagnoses don’t come out of thin air. There is evidence that law enforcement agencies pressure medical examiners to minimize culpability when investigating deaths in custody, even to the point of withholding evidence.

In California, for example, coroners’ offices are often located within sheriffs’ offices, rather than operating independently, which can place them under extreme pressure to return certain results, or hamper their authority to demand the evidence to which they are entitled. Michelle Jordan, a medical examiner in Santa Clara, described an environment where she had to appeal to the county counsel and county executive for information pertinent to her autopsies, and was asked to sign documents accepting limits on her work. Until 2016, the state didn’t even require that the people performing autopsies be doctors.

California is not an exception: Surveys of medical examiners found that 22 percent of the death investigators have experienced pressure from political officials to change findings in an investigation.

Without independent death investigations, it will be hard to ensure police accountability. Medical examiners and coroners’ findings serve as important evidence in legal proceedings against police officers who kill civilians, and their reporting on death certificates can help researchers track patterns of police violence across the United States. The Hennepin County Medical Examiner ultimately reported George Floyd’s death as a homicide, but few deaths in custody ever receive this level of public attention. If we want the truth about the deaths of Floyd and other people like him, we have to make sure that death investigators are free to seek it out and to speak it publicly.

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