No Graves As Yet — Anne Perry

On a sunny afternoon in late June 1914, Cambridge professor Joseph Reavley learns that his parents have died in an automobile crash. Joseph's brother, an officer in the Intelligence Service, reveals that their father had been en route to London with a mysterious secret document--allegedly possessing the power to disgrace England and destroy the civilized world. Now that explosive paper has vanished, and Joseph is left to wonder: How had it fallen into the hands of his father, a quiet countryman? But Joseph is soon burdened with a second tragedy: the shocking murder of his most gifted student, who was loved and admired by everyone. Or so it appeared. And as England's seamless peace begins to crack, the distance between the murder of an Austrian archduke and the death of a brilliant student grows shorter every day.