A demonstrator was shot and killed at Salt Lake City's “No Kings” protest when a man believed to be part of the event's peacekeeping team fired at another man allegedly aiming a rifle at protestors, authorities said Sunday. Police took the alleged rifleman, Arturo Gamboa, 24, into custody Saturday evening on a murder charge, Salt Lake City Police Chief Brian Redd said at a Sunday news conference. The bystander, Arthur Folasa Ah Loo, 39, died at the hospital.