The Tusla reserve deputy who said he mistakenly fired his gun instead of his Taser and killed Eric Harris was investigated by the Sheriff's Office in 2009, CBS reported Wednesday. Robert Bates, 73, was the focus of an internal investigation over whether he received preferential treatment and was properly trained. The inquiry found concerns with his behavior in the field and that his training was questionable. Bates pleaded not guilty to second-degree murder charges in the death of Harris, who died at a hospital after a sting operation involving the sale of illegal weapons went wrong. Bates said he mistakenly reached for his gun instead of his taser when he fatally shot the 44-year-old.