A Duty to the Dead (Charles Todd)

In this moving mystery set in WWI England, an Army nurse on leave goes to deliver a deathbed message from one of her patients, and winds up picking at loose ends until an entire family history unravels. At the core of the mystery is the 14-year-old murder of a servant girl, apparently by a teenage son of the family, but it links through time to a killing today and a heartbreaking miscarriage of justice. The horrible maltreatment of a young boy, even more than the killings, tore at my heart. I will definitely read more by this author.