Atlee Pine series

"FBI Agent Atlee Pine's search for her sister Mercy clashes with military investigator John Puller's high-stakes case, leading them both deep into a global conspiracy -- from which neither of them will escape unscathed"--provided by publisher.

Atlee Pine, an FBI special agent, is called in to investigate the mutilated carcass of a mule found in the Grand Canyon--and hopefully, solve the disappearance of its rider. But this isn't the only recent disappearance. In fact, it may be just the first clue, the key to unraveling a rash of other similar missing persons cases in the canyon.