SACRAMENTO, Calif. – Dripping sweat and coughing on dusty air, Joe Griffin prepares to make yet another trek up a rocky hillside. Over the course of a month, he will take this short hike hundreds of times. Luckily, the altitude of Laos’s mountainous Xiangkhoang Province provides a small measure of relief from the heat and humidity. Each trip up the mountain concludes with Griffin sifting through buckets upon buckets of dirt and soil, searching for a clue – any clue – to find the remains of an American pilot who crashed nearly a half century ago.