Police officer Brian Sicknick suffered strokes and died a day after facing a seditious crowd of supporters of former President Donald Trump during the January 6 invasion of the U.S. Capitol on January 6.
The finding could make it difficult, if not impossible, to bring murder charges on Sicknick's death. Two men were arrested last month and charged with attacking the officer with a chemical spray.
The 42-year-old Sicknick was "sprayed with a chemical substance outside the US Capitol" during the invasion at around 2:20 pm, as the office of chief physician Francisco Diaz noted in the decision.
Around 10 p.m. that night, Sicknick collapsed in the Capitol and was rushed to a hospital, Diaz's office discovered. He died there at 9:30 p.m. the following evening.
According to the doctor's office, Sicknick's official cause of death was "acute brainstem and cerebellar infarction due to acute thrombosis of the basilar artery".
The officer’s death mode – the circumstances surrounding his death – was "natural," the bureau said. This term is used when death is caused solely by illness and not hastened by injury.
But, in an interview with the Washington Post, Diaz noted Sicknick's role in confronting the rioters hours before his collapse, saying, "Everything that happened played a role in his condition."
Even so, Diaz told the newspaper that Sicknick's autopsy found no evidence that the officer was allergic to the chemical irritants that were sprayed on him during the riot.
Capitol Police said in a press release on the day of Sicknick's death that he "died of on-duty injuries".
In a statement Monday night to NBC News, USCP said it accepted the findings from Diaz's office, "but that doesn't change the fact that Officer Brian Sicknick died on duty and bravely defended Congress and the Capitol . "
"The department continues to mourn our beloved colleague. The attack on our officers, including Brian, was an attack on our democracy," said the USCP. It added that law enforcement agencies "will continue to ensure that those responsible for attacking officials are held accountable".
The medical examiner's decision about Sicknick's death was seen as a determining factor in whether Julian Khater and George Tanios could be charged with murder.
The two men are accused of attacking Sicknick and other officials with a substance similar to bear spray. You are currently not accused of killing Sicknick.
Michael Sherwin, the federal attorney who led the investigation into the Capitol attack, told CBS News "60 Minutes" in March that he would face murder charges if the coroner decided the spray had a role in Sicknicks Death plays.
"If evidence links that chemical directly to his death, yes. We have a cause, we have a connection. Yes. In this scenario, it's a murder case," Sherwin told CBS.