Tony Hillerman. SKELETON MAN. Harper, 2004.
Two planes crash in 1956, scattering bodies and body parts into the Grand Canyon. A passenger with a case of diamonds handcuffed to his wrist was never found. When one diamond shows up fifty years later after a burglary, the rightful heir goes looking, with the help of locals including retired Lt. Leaphorn, Chee, Bernie, Cowboy, & his cousin. Rain causes flash flooding.