On April 21, 2011, at an elegant three-story town house in the city of Nantes at the western end of the Loire Valley, French police discovered five bodies, all of them members of the notable Dupont de Ligonnès family, including the mother, Agnès, and her four children, Benoît, Anne, Thomas, and Arthur, ages 13 to 20. Each had been shot dead and each had been buried in the garden, along with the family’s two Labrador dogs. The sight stunned police.

Yet it wasn’t until they had fully examined the crime scene that investigators realized something was missing: namely the body of Xavier Dupont de Ligonnès, the father of the family and the sole male heir to one of France’s oldest familles de noblesse. In that moment he became one of France’s most wanted fugitives.