BALTIMORE (NewsNation Now) — Maryland officials said they will review all in-custody death reports during the tenure of the state’s former chief medical examiner after he testified that former Minneapolis police officer Derek Chauvin was not responsible for George Floyd’s death.

Dr. David Fowler, Maryland’s chief medical examiner from 2002 to 2019, was a key defense witness for Chauvin, who was convicted Tuesday of murder and manslaughter for kneeling on Floyd’s neck for more than nine minutes.

The announcement of the investigation came from Attorney General Brian Frosh and Gov. Larry Hogan on Friday, less than 24 hours after the attorney general’s office received a letter from D.C.’s former chief medical examiner Roger Mitchell, and signed by 431 doctors from around the country, saying Fowler’s conclusions were so far outside the bounds of accepted forensic practice that all his previous work could come into question.

“Dr. Fowler’s stated opinion that George Floyd’s death during active police restraint should be certified with an ‘undetermined’ manner is outside the standard practice and conventions for investigating and certification of in-custody deaths. This stated opinion raises significant concerns for his previous practice and management,” the letter said.

Fowler testified that the primary cause of Floyd’s death was a sudden heart rhythm disturbance during police restraint due to underlying heart disease, contradicting several experts who said Floyd died due to a lack of oxygen. He also said that Floyd’s drug use and exposure to carbon monoxide from the police car contributed to his death.

“We agree that it is appropriate for independent experts to review reports issued by the Office of the Chief Medical Examiner (OCME) regarding deaths in custody,” Raquel Coombs, a spokeswoman for Frosh, said in a statement.

Fowler told The Baltimore Sun he was not aware of any such consideration of a review and defended the work of his office, noting that he was not solely responsible for autopsy conclusions.

“There’s a large team of forensic pathologists, with layers of supervision, and those medical examiners always did tremendous work,” Fowler said Friday. He declined to discuss his testimony in the Chauvin trial.

Bruce Goldfarb, a spokesman for the chief medical examiner’s office, said the agency is “committed to transparency and will cooperate fully with an inquiry.”

Coombs said the review of death determinations will not involve any state officials or staff connected to a lawsuit filed by the family of Anton Black, a 19-year-old who died in police custody in Greensboro in 2018.

Black’s death was captured on video, which showed Greensboro police holding the unarmed teenager down for more than six minutes. Fowler ruled that Black died because of a sudden cardiac event while struggling with police, and not because they pinned him in a prone position.

The attorney general’s office is defending the state in the lawsuit brought by Black’s family against Fowler, the state and others. They have asked for the Black case to be thrown out.

“We have taken steps to wall off those in our office who are representing the (Office of the Chief Medical Examiner) and its current and former employees, including Dr. Fowler, from those who might be involved in any review of (the examiner’s) reports,” Coombs wrote.

Included in the time period to be reviewed is the death of Tyrone West, who died after struggling with Baltimore police following a traffic stop in 2013. Witnesses and the officers themselves said there was a violent struggle between the officers and West, but the state medical examiner’s office ruled that he died from natural causes exacerbated by the struggle and the summer heat.

West’s sister, Tawanda Jones, has been fighting for eight years to get her brother’s case re-opened. She said word of the review was “the best news I’ve gotten all day.”

One of Fowler’s office’s best-known rulings came in the death of Freddie Gray. According to the ruling, Gray died from injuries suffered in the back of a police van. The autopsy concluded that officers’ failure to take care of him and seek medical attention made his death a homicide, and prompted State’s Attorney Marilyn Mosby to swiftly file charges against six officers. All were either acquitted or had their charges dropped.

Brian Peterson, chief medical examiner for Milwaukee County, said he and Fowler have been friends for years and served together on committees. Peterson told The Washington Post he finds the investigation into Fowler’s time as chief medical examiner unnecessary and called Fowler an “excellent, experienced forensic pathologist.”

Despite multiple attempts, Fowler has not responded to NewsNation’s request for comment.