Federal authorities have arrested and charged two men with assaulting U.S. Capitol Police officer Brian D. Sicknick with an unknown chemical spray during the Jan. 6 Capitol riot but have not determined whether the exposure caused his death.

Julian Elie Khater, 32, of Pennsylvania and George Pierre Tanios, 39, of Morgantown, W.Va., were taken into custody Sunday. Authorities said they grew up together in New Jersey.

“Give me that bear sh--,” Khater said to Tanios on video recorded at 2:14 p.m. at the Lower West Terrace of the Capitol, where Sicknick and other officers were standing guard behind metal bicycle racks, arrest papers say.

About nine minutes later, after Khater said he had been sprayed with something, Khater is seen on video discharging a canister of a toxic substance into the face of Sicknick and two other officers, arrest papers allege.

Two men who were arrested and charged with assaulting U.S. Capitol Police officer Brian D. Sicknick are seen in a Jan 6. video outside the Capitol. (The Convo Couch)

Khater and Tanios are each charged with nine counts, including assaulting three officers with a deadly weapon — Sicknick, another U.S. Capitol Police officer identified as C. Edwards and a D.C. police officer identified as B. Chapman. They are also charged with civil disorder and obstruction of a congressional proceeding. The charges are punishable by up to 20 years in prison.

More than 300 people have been charged in the assault on the Capitol, with charges expected for at least 100 more in what authorities describe as one of the largest investigations in American history. More than 40 people stand accused of assaulting police officers, who were punched, choked, dragged down stairs and beaten with their own riot shields.

Sicknick died one day after the riot. The case involving his death has been one of the biggest mysteries, absent a definitive ruling on how he died and whether anyone would, or could, be held accountable. Autopsy results remain pending almost 10 weeks after the insurrection.

Acting Capitol Police chief Yogananda Pittman said Monday that the investigation of Sicknick’s death, led by D.C. police and the FBI, remains active. In a statement, she called the assaults on officers “an attack on our democracy,” adding that “those who perpetrated these heinous crimes must be held accountable.”

Tanios’s sister, Maria Boutros, a real estate agent in New Jersey, said when reached by phone Monday that her brother “was arrested for something he didn’t do. He didn’t do it. He would never do that.”

Khater was arrested in Newark, according to an unsealed arrest warrant signed by U.S. Magistrate Zia Faruqui on March 6. Efforts to contact Khater family members for comment were not successful.

Prosecutors filed charges in the Sicknick case after tipsters contacted the FBI identifying Khater and Tanios from wanted images released by the bureau from surveillance video and officer-worn body-camera footage, the complaint says. Each has operated a food business catering to students in college towns.

According to a LinkedIn page that appears to belong to Khater and is referenced in court documents, he runs a smoothie shop near Pennsylvania State University. The student newspaper, the Daily Collegian, reported it has a “for lease” sign in its window.

Tanios operates Sandwich University, an eatery in Morgantown, home to West Virginia University. The complaint says Tanios was wearing clothing with his business insignia at the riot, which helped to identify the self-proclaimed “king of the fat sandwich.”

The men made separate appearances in court Monday — Khater in New Jersey, Tanios in West Virginia — and both were ordered held until further proceedings. Neither spoke beyond giving perfunctory answers. Their attorneys did not return calls seeking comment.

Khater’s attorney urged his client be transferred to the District as soon as possible. Tanios has a detention hearing scheduled for Thursday in West Virginia.

Questions remain about whether anyone will be held criminally responsible in Sicknick’s death. Without a cause of death, his case has not been established as a homicide.

It remains unclear what role if any the video-recorded assault on Sicknick played in his death. Investigators have also determined that he did not die of blunt-force trauma, people familiar with the matter said, speaking on the condition of anonymity to discuss an ongoing investigation.

An FBI agent alleged in charging papers that publicly available video showed that after Khater asked for the spray, Tanios replied: “Hold on, hold on, not yet, not yet . . . it’s still early.” The agent said the exchange showed that the two were “working in concert and had a plan to use the toxic spray against law enforcement.”

The agent asserted that the men “appeared to time the deployment of chemical substances to coincide with other rioters’ efforts to forcibly remove the bike rack barriers that were preventing the rioters from moving closer to the Capitol building,” using their hands, ropes and straps.

All three officers were temporarily blinded and incapacitated for more than 20 minutes “as a result of being sprayed in the face with an unknown substance by Khater,” and Edwards sustained scarring beneath her eyes for several weeks, charging papers said.

Charging papers include a photograph that the FBI agent said shows Khater “holding a white can with a black top that appears to be a can of chemical spray.” It adds that the officers reported the substance to be “as strong as, if not stronger than, any version of pepper spray they had been exposed to” in their police training.

Authorities have said that 139 police officers were assaulted by Trump supporters wielding sledgehammers, baseball bats, hockey sticks, crutches and flagpoles. Police have testified that at least 800 people entered the Capitol after a smaller number forced their way in, seeking to block Congress from confirming the November presidential election victory of Joe Biden.

In early February, Sicknick, 42, who grew up in South River, N.J., became the third officer in history to lie in honor in the Capitol Rotunda, where fellow officers, lawmakers and President Biden and first lady Jill Biden came to pay respects to the 13-year Capitol Police veteran and former New Jersey Air National Guard member.

Sicknick died at a hospital about 9:30 p.m. Jan. 7. Authorities have included Sicknick among five people who died as a result of the riot. The four others were civilians — Ashli Babbitt, 35, who was shot by an officer, and three others who died in the chaos.

Referring to Sicknick, a House-passed article of impeachment charged Trump with inciting insurrection, alleging that members of a crowd he addressed “injured and killed law enforcement personnel.” Trump was acquitted after 57 senators voted to convict him for inciting the attack, 10 short of the two-thirds majority needed.

Then-acting U.S. attorney general Jeffrey A. Rosen said in a statement shortly afterward that Sicknick died of “the injuries he suffered defending the U.S. Capitol,” echoing a statement by Capitol Police.

The Capitol Police said that Sicknick “was injured while physically engaging with protesters” and collapsed after he returned to his office following the riot.

The case remains a top priority for investigators — the FBI, Capitol Police and D.C. police, which handles all deaths in the District — with Rosen saying authorities would “spare no resources in investigating and holding accountable those responsible.”

The day after Sicknick died, his family issued a statement noting “many details regarding Wednesday’s events and the direct causes of Brian’s injuries remain unknown and our family asks the public and the press to respect our wishes in not making Brian’s passing a political issue.”

Sicknick’s family has not spoken publicly, and their spokeswoman said in February they decided against conducting interviews. Sicknick’s brother did not respond to questions on Monday.

Sen. Cory Booker (D-N.J.) paid tribute to Sicknick on the Senate floor, describing Sicknick’s death as a “crime” that “demands the full attention of federal law enforcement.”

Julie Tate, Alice Crites and Dalton Bennett contributed to this report.