The Last Tour of Duty — A.P. Greenwood

In 1970, with nineteen years of service, and after his second tour of duty in Vietnam, Lieutenant Commander Alex Wolfe is assigned his final duty station, Naval Facility Cape Hatteras with its secret mission of using passive sonar systems to track the movement of Soviet submarines. He is told that nothing exciting ever happens at a Navfac. But within a few days of his arrival, a murdered sailor's body is discovered in the nearby woods, and then a Soviet nuclear submarine is lost at sea under suspicious circumstances. Alex must investigate both, but still finds enough time to become enamored with a popular local widow who has a secret of her own. As he gets closer to solving the mysteries, Alex makes a shocking discovery. Someone he once trusted with his life has targeted him for murder.