The District of Columbia's chief medical examiner has ruled that Capitol Police Officer Brian Sicknick had two strokes and died of natural causes, after he tussled with a mob of supporters of former President Donald Trump at the U.S. Capitol. 

The medical examiner's office said on Monday that the 42-year-old officer's cause of death was natural causes after he suffered a stroke. He died the day after the January 6 violence. 

The findings mean it will be hard for federal prosecutors to bring homicide charges in connection with Sicknick's death. 

Two men, George Tanios and Julian Khater, are facing charges they assaulted three police officers, including Sicknick, by spraying them with a chemical irritant on January 6. 

The Washington Post first reported the medical examiner's ruling.