2 men arrested in assault on Capitol Police officer Brian Sicknick

The Justice Department has arrested and charged two men who allegedly assaulted Capitol Police officer Brian Sicknick with bear spray during the riot at the U.S. Capitol, as authorities continue working to determine whether the assault was a direct cause of Sicknick's death.

Julian Elie Khater of Pennsylvania and George Tanios of Morgantown, West Virginia, were arrested Sunday and made their initial appearances in federal court Monday afternoon.

In a newly-unsealed affidavit, an FBI special agent cited videos showing the series of events leading up to and after the assault on Sicknick and two other officers guarding a bike rack barrier at the Capitol.

The affidavit points to one open-sourced video where Khater is seen telling Tanios to hand him a spray canister near the Lower West Terrace of the Capitol at 2:14 p.m.

"Give me that bear sh**," Khater says.

"Hold on, hold on, not yet... it's still early," Tanios then replies.

Six minutes later, Khater is allegedly seen walking through the crowd up to a bike rack barrier being guarded by Officer Sicknick and two other officers -- he then sprayed them with what the FBI describes as an "unknown chemical substance" from roughly five to eight feet away, the affidavit alleges.

The affidavit includes screengrabs from police body camera video and surveillance footage showing the three officers pulling back from the barrier to find water to wash out their eyes, though Khater allegedly continued spraying in their direction before an officer engages him and starts pepper spraying him back.

The officer in the blue jacket and bike helmet bending over has been identified by a source as Sicknick reacting to being sprayed.

The affidavit notes that all three officers including Sicknick "were incapacitated and unable to perform their duties for at least 20 minutes or longer while they recovered from the spray." One officer said the spray was "as strong as, if not stronger than, any version of the pepper spray they had been exposed to during their training as law enforcement officers."

Both men have been charged with three counts of assaulting federal officers, conspiracy to injure officers, civil disorder, obstruction of an official proceeding, physical violence on restricted grounds, violent entry and aiding and abetting.

Khater and Tanios made their initial appearances in front of magistrate judges in New Jersey and West Virginia, respectively, on Monday afternoon.

Both were ordered to remain in government custody pending formal detention hearings in their case.

Donning a blue mask and dressed in an orange jumpsuit, Tanios repeatedly shook his head as West Virginia Magistrate Judge Michael Aloi read off the charges against him.

Neither men entered formal pleas in their initial appearances, though an attorney for Khater in his hearing indicated he plans to plea not guilty to the charges against him.