SIOUX FALLS, S.D. — From far away it looked as if a bottle of red wine had been spilled along the icy gravel, an image Lee Litz would not soon forget. He was test-driving a Jeep near a cornfield on the outskirts of Sioux Falls, South Dakota, when he saw it: a deep red blanket protruding from a ditch. It struck Litz as peculiar that afternoon, Feb. 28, 1981, and so he pulled the car over and stepped out into the dirt and the cold. He knelt down to see what it was, as he later recounted to the Argus Leader.