Free Fire — C.J. Box

Joe Pickett's been hired to investigate one of the most cold- blooded mass killings in Wyoming history. Attorney Clay McCann admitted to slaughtering four campers in a backcountry corner of Yellowstone National Park--a "free-fire" zone with no residents or government regulation. In this remote fifty-square-mile stretch a man can literally get away with murder. Now McCann's a free man, and Pickett's about to discover his motive--one buried in Yellowstone's rugged terrain, and as dangerous as the man who wants to keep it hidden.