Open Season by CJ Box

Joe Pickett is the new game warden in Twelve Sleep, Wyoming, a town where nearly everyone hunts, and the game warden--especially one like Joe who won't take bribes or look the other way--is far from popular. When he finds a local hunting outfitter dead, splayed out on the woodpile behind his state-owned home, he takes it personally. There had to be a reason that the outfitter, with whom he's had run-ins before, chose his backyard, his woodpile to die in. Even after the "outfitter murders," as they have been dubbed by the local press after the discovery of the two more bodies, are solved, Joe continues to investigate, uneasy with the easy explanation offered by the local police.

As Joe digs deeper into the murders, he soon discovers that the outfitter brought more than death to his backdoor: he brought Joe an endangered species, thought to be extinct, which is now living in his woodpile. But if word of the existence of this endangered species gets out, it will destroy any chance of InterWest, a multi-national natural gas company, building an oil pipeline that would bring the company billions of dollars across Wyoming, through the mountains and forests of Twelve Sleep. The closer Joe comes to the truth behind the outfitter murders, the endangered species and InterWest, the closer he comes to losing everything he holds dear.

Image from Thriftbooks.com and book description from Goodreads.com