Free today from Amazon courtesy of Stackpole Books: Faded Coat of Blue
by Owen Parry, a historical thriller and mystery set during the civil war, originally published in 1999 by William Morrow & Company. Excellent reviews from Publisher's Weekly and Booklist. High ratings at Goodreads.
Abel Jones, a Welsh immigrant and Union army enlistee, investigates the death of Anthony Fowler, a young volunteer captain whose murder is blamed on the Confederates. Jones pursues the blood of the battlefield through the intrigues of Washington, D.C., where evil and good intertwine in this Owen Parry novel of the Civil War.