The Coffee Killer - Motel at the End of the World, #1

Welcome to the Crescent Motel, a waypoint in a post-apocalyptic no man's land. At the helm are Darrell, the middle-aged mustachioed manager, and his danger-sniffing dog Bruno. When he and the motel's housekeeper, Nance, discover one of the guests dead, they decide to keep the body under wraps until they root out the killer. But before they have a chance, two mysterious men appear, looking for answers.
When the first body disappears and is replaced by another, Darrell and Nance realize they're in over their heads.