Two men charged with alleged assault on Capitol Police Officer Brian Sicknick, who died after riot

Federal law enforcement authorities have arrested and charged two men with assaulting U.S. Capitol Police officer Brian Sicknick with bear spray during the Jan. 6 riot at the Capitol building, but the cause of his death is still unknown.

Julian Khater, 32, of Pennsylvania and George Tanios, 39, of West Virginia were arrested Sunday and will appear in federal court Monday, the Washington Post reports. The two men were allegedly seen on video recordings taken at the Lower West Terrace of the Capitol at 2:14 p.m., where Sicknick and other police officers were standing guard behind metal bicycle racks.

Arrest papers obtained by the Post allege that Khater asked Tanios for bear spray, which he later appears on video to discharge into the face of Sicknick and two other police officers.

The two men are charged with nine counts including assaulting three officers with a deadly weapon, civil disorder, and obstruction of a congressional proceeding. If convicted, they could each face up to 20 years in prison.

Officer Sicknick was one of five people who died during and after the riot. Kevin Greeson, 55, of Athens, Alabama; Benjamin Philips, 50, of Ringtown, Pennsylvania; and Rosanne Boyland, 34, of Kennesaw, Georgia, died of medical emergencies. Ashli Babbitt, 35, was fatally shot by police during a confrontation inside the Capitol building. Initial reports suggested that Sicknick had died from blunt force trauma after being struck by a fire extinguisher, but later reporting revealed that medical examiners did not find signs that the officer sustained any blunt force trauma.

A spokeswoman for the deputy mayor for public safety in D.C. told the Washington Post that autopsy reports for Sicknick are still pending as of Monday. Police have not determined the cause of Sicknick's death and have not charged Khater and Tanios with homicide. Police said surveillance video and officer-worn body camera footage show clear evidence of the assault, regardless of whether those actions led to the officer's death.

The Associated Press reported that investigators theorize Sicknick may have ingested the chemical substance he was sprayed with, possibly contributing to his death at a hospital the next day.

More details from the AP:

Khater is the man in a video obtained by the FBI that showed him spraying Sicknick and others with bear spray, according to court papers.

"Give me that bear (expletive), Khater said to Tanios on the video, according to court papers. Sicknick and other officers were standing guard near metal bike racks, the papers say.

Khater then says, "they just (expletive) sprayed me," as he's seen holding a white can with a black top that prosecutors said "appears to be a can of chemical spray."

After he sprayed the officers, they "immediately retreat from the line, bring their hands to their faces and rush to find water to wash out their eyes," according to the court papers.

The FBI has released some 250 photos of suspects wanted for assaulting federal law enforcement officers on Jan. 6 at the Capitol. The Department of Justice recently said said more than 300 individuals have been charged relating to the riot, over 900 search warrants have been executed nationwide, and 15,000 hours of surveillance tape is being reviewed by authorities to identify suspects.