A 16-year-old boy shot five people in a confrontation between two groups at a carnival in a Salt Lake City suburb Sunday, killing three of them including an 8-month-old infant

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.

As prosecutors consider potential criminal charges against the man whose alleged actions caused the shooting death of another man during Saturday's "No Kings" protest, the investigation into the so-called "peacekeeper" who actually fired the fatal shot also continues.