An operator of a highly popular YouTube channel dedicated to high-powered guns and explosives was found mysteriously shot to death, authorities said. Keith Ratliff, who was a business partner at FPSRussia, YouTube's ninth most popular channel with more than three million active subscribers and a combined half billion views, was discovered on a rural road in Carnesville, Georgia. Ratliff had a single gunshot wound the head and police are treating his death as a homicide.