Zero Day by David Baldacci
John Puller is a combat veteran and the best military investigator in the U.S. Army's Criminal Investigative Division. His father was an Army fighting legend, and his brother is serving a life sentence for treason in a federal military prison. Puller has an indomitable spirit and an unstoppable drive to find the truth.
Now, Puller is called out on a case in a remote, rural area in West Virginia coal country far from any military outpost. Someone has stumbled onto a brutal crime scene, a family slaughtered. The local homicide detective, a headstrong woman with personal demons of her own, joins forces with Puller in the investigation. As Puller digs through deception after deception, he realizes that absolutely nothing he's seen in this small town, and no one in it, are what they seem. Facing a potential conspiracy that reaches far beyond the hills of West Virginia, he is one man on the hunt for justice against an overwhelming force.