The Yard Dog: a Mystery (Hook Runyon Mystery) First edition

The Yard Dog takes place near the close of World War II, when a large number of Nazi POWs were incarcerated in camps scattered across the prairies of the United States. 

At Waynoka Divisional Point, near POW Camp Alva, the disillusioned Hook Runyon is assigned by the railroad to run off hobos and arrest pickpockets. Left behind in the war because of the loss of his arm in a car accident, Hook lives in a caboose, collects rare books, and drinks busthead liquor. When a coal picker by the name of Spark Dugan is found run over by a reefer car, Hook and his sidekick, Runt, the local moonshiner, suspect foul play and are drawn into a scheme far greater than either could have imagined. This conspiracy reaches the highest echelons of the camp and beyond and will push Hook and Runt to their physical and mental limits.

Hook is a complex character, equal parts rough and vulnerable, an unlikely and unwilling hero. He is more than matched by Dr. Reina Kaplan, a Jewish big-city transplant to Camp Alva who is battling her own demons and has been put in charge of educating the Nazi inmates in the basics of democracy before their eventual return to Germany.

Vivid descriptions of period detail, stark landscapes, and unique characters make this first book in the Hook Runyon series a fascinating mystery full of tension and deep insight.