A man who was believed to be part of a peacekeeping team for the “No Kings” protest in Salt Lake City shot at a person who was brandishing a rifle at demonstrators, striking both the rifleman and a bystander who later died at the hospital, authorities said Sunday.

A bystander was fatally shot after security members at the demonstration confronted a man who was running toward the crowd with an AR-15-style rifle, the police said.

Utah resident Arthur Folasa Ah Loo, 39, was shot and critically wounded during the protest in Salt Lake City on Saturday, June 14. He later died in the hospital from his injuries, the Salt Lake City Police Department confirmed in a news release.