Two men have been arrested and charged with assaulting U.S. Capitol Police officer Brian Sicknick during the Jan. 6 Capitol insurrection. Authorities say the assailants used bear spray against Sicknick, who died shortly after the riot.

The two suspects, George Tanios of West Virginia and Julian Khater of Pennsylvania, were expected to appear in federal court on Monday (March 15). Since the Capitol attack, the Justice Department says around 300 rioters have been arrested and many have been charged with wielding bats, chemical irritants and metal barricades against Capitol Police. However, Tanios and Khater are the first two rioters to be charged in connection with the deaths that occurred during and after the attack.

According to the Associated Press, police initially believed Sicknick was struck in the head with a fire extinguisher. However, as the investigation has progressed, authorities now believe the officer could have ingested a chemical substance — such as bear spray — that ultimately led to his death.

Khater was identified in a video obtained by the FBI, which showed him spraying Sicknick and others with the spray. According to court documents, Khater yelled to Tanios, “Give me that bear [spray].”

After spraying Sicknick and other officers, the men “immediately retreat[ed] from the line, [brought] their hands to their faces and rush[ed] to find water to wash out their eyes,” court documents read.

Khater also said, “They just fucking sprayed me” in the clip and was seen holding a white can with a black top that prosecutors described as “a can of chemical spray.”

Sicknick later collapsed and died at a hospital the next day. The medical examiner’s report is still incomplete and the official cause of his death has not yet been determined. According to Capitol Police, Sicknick died after being injured “while physically engaging with protesters.” The department added that they are awaiting toxicology results and said his death is considered in the line-of-duty.

The Justice Department’s federal murder investigation into Sicknick’s death is ongoing.