SANGIN, Afghanistan – For a minute, it seemed like a manhunt in the hills of the Upper Sangin Valley was possible. Pushing out from Forward Operating Base Tabac early Saturday, Marines with Dog Company, 1st Battalion, 7th Marines, noticed a man on a nearby hill holding a metallic black object that was glinting in the sunlight. The assumption: The stranger was carrying a radio, making it entirely possible a Taliban spotter was spying on the patrol. “I saw it glistening in his hand,” said Lance Cpl. Christopher Sanders, making his way through a green field of thigh-high wheat. “There isn’t…