Walter Reed patient Sgt. James Doyle went missing this afternoon after leaving a message he was suicidal, Washington, D.C. news station WJLA-TV reported tonight. He was last seen at a gas station in Montgomery County.Doyle, 25, served two tours in Iraq and is being treated at Walter Reed for PTSD. From video camera footage from the gas station, Doyle appears to be white. He was wearing a gray t-shirt, a black ball cap and sunglasses.