Federal authorities have arrested and charged two men with assaulting U.S. Capitol Police officer Brian D. Sicknick with bear 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 arrested Sunday and are expected to appear in federal court Monday.

Khater and Tanios are 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, the Washington Post reports.

Prosecutors filed charges after tipsters contacted the FBI allegedly identifying Khater and Tanios from wanted images released by the bureau from surveillance video and officer-worn body camera footage, the complaint said. It said the men grew up together in New Jersey, and that Khater had worked in State College, Pa., and Tanios owns a business in Morgantown.

Sicknick died at a hospital about 9:30 p.m. Jan. 7, one day after the riot at the U.S. Capitol.

Autopsy results for Sicknick were still pending as of Monday, according to a spokeswoman for the deputy mayor of public safety in D.C. Without a cause of death, his case has not been established as a homicide, although charging papers allege that evidence of an assault on Sicknick is clear on video.