Damage Control by J.A. Jance

On a beautiful sunny day in the Coronado National Monument, an elderly couple's car goes off the side of a mountain and into oblivion. The terrain is so rocky that a helicopter must be flown in to retrieve the bodies, and to make matters worse, a thunder-storm is looming on the horizon. Hours later and miles away, the subsiding rain reveals gruesome evidence: two trash bags containing human remains.