By MICHAEL BALSAMO and ALANNA DURKIN RICHER

WASHINGTON (AP) — U.S. officials have arrested and charged two men with assaulting U.S. Capitol Police officer Brian Sicknick with bear spray during the Jan. 6 riot, but they do not know yet whether it caused the officer’s death.

Thirty-nine-year-old George Tanios, of Morgantown, West Virginia, and 32-year-old Julian Khater, of Pennsylvania, were arrested Sunday.

Get our free mobile app

The idea that Sicknick died after being sprayed by a chemical irritant has emerged in recent weeks as a new theory in the case. Investigators initially believed that Sicknick was hit in the head with a fire extinguisher.

An email seeking comment was sent to Tanios’ lawyer. A person who answered the phone at the office of Khater’s lawyer said they had no comment.

PHOTOS: Scene at U.S. Capitol shows chaos and violence