Cold barrel zero
(Book)

John Hayes is a Special Operations legend who went rogue on a deep-cover mission and betrayed his own soldiers. Disgraced and on the run, he returns to the United States to take revenge on his accusers with a series of devastating attacks. Only one man can stop him: Thomas Byrne. He once fought alongside Hayes as a combat medic. Now a surgeon, he moves from town to town, trying to forget his past, until he is called upon by a high-ranking government official to help capture the man he once called a friend. With the fate of the nation hanging in the balance and nothing as it seems, both men must decide whom to trust--and whom to betray.