What caused the death of Brian Sicknick, a Capitol Police officer who died after "physically engaging" rioters on Jan. 6 at the US Capitol, remains murky, but it appears the FBI has narrowed its focus on an assailant seen on video attacking officers during the riot. Sources tell the New York Times and Washington Post that video evidence shows a person going after Sicknick and other officers with a chemical irritant, possibly bear spray, during the attack, though the person hasn't been identified and it's not clear if the irritant is what directly caused Sicknick's death. CNN notes it's a most "difficult case for investigators," as for weeks they've gone over videos and photos trying to pinpoint exactly when Sicknick, 42, was fatally harmed.
At first it was reported that Sicknick—who died at the hospital after he "collapsed" at his division office following his return from the Capitol, per a Jan. 7 Capitol Police statement—had been struck with a fire extinguisher, but investigators later determined that not to be the case, and they've since said he didn't die of blunt force trauma. Although chemical irritants like bear spray and pepper spray are considered nonlethal crowd-control measures, individuals with underlying conditions could suffer physical reactions and injury from them. It's not clear what charges could be brought against a suspect, as it may be hard to prove such a spraying caused his death; the Times and the Post note that assault against an officer would be a more likely charge than murder. "We are awaiting toxicology results and continue to work with other government agencies regarding the death investigation," Capitol Police said in a Friday statement. (Read more Capitol attack stories.)