SALT LAKE CITY — A military veteran who was trying to stop an alleged gunman and inadvertently shot and killed a demonstrator at a Salt Lake City “No Kings” rally was a “safety volunteer” for the demonstration, according to police and organizers. The safety volunteer fired three rounds at Arturo Gamboa, 24, who had allegedly brandish a rifle at the crowd, hitting both Gamboa and a protester on Saturday, police said. Gamboa never shot the rifle, but was arrested on a murder charge and accused of