The Seventh Sacrament — David Hewson

When seven-year-old Alessio Bramante vanished, there was plenty of blame to go around. His father, a charismatic professor of archaeology, inexplicably left Alessio alone near a labyrinth of ancient tunnels and excavations. And then there were the police: an officer left Giorgio Bramante in a room with the prime suspect, allowing' Alessio's father to beat the man to death.

Now fourteen years have passed. Giorgio has been freed from prison, and one by one, those connected to the boy's disappearance are dying. As Detective Nic Costa and his fellow investigators scramble to find Giorgio, they are thrust into a darkening web of secret passions past and present. But at the heart of this case -- as close and as far away as Rome's underground treasures -- is the unanswered question: what really happened to little Alessio and why was his body never found?