The full-length bronze memorial on the empty grave in Pickens hints at how Ross Walker died.“Perished over the Pacific Ocean,” says the marker at Hillcrest Memorial Park.That is all the Walker family and the families of 92 other servicemen aboard Flying Tiger Line Flight 739 know.The military charter jet on route to Saigon was lost over the deepest part of the Pacific Ocean on March 15, 1962, three years before President Lyndon Johnson sent combat troops to Vietnam.No wreckage was found, not a seat cushion or life vest. No remains.Their mission was so top secret, the military has revealed nothing...