This is the first in a series featuring Nic Costa and Inspector Falcone. Sara Faranese is studying in the Vatican library when a colleague rushes in and frankly whispers, "In the blood of the martyrs is the seed of the church." He then displays a pistol and a bag containing the skin of a human being. Fearing for her safety a Swiss guard shoots him dead, much to Sara's consternation, because she realized he wasn't trying to kill her, but to convey a message. Realizing that the flayed skin may have some reference to St. Bartholome and she drags Coasta and his partner Rossi to that saints church where they discover two more flayed bodies, her erstwhile lover and Stefano Rinaldi's wife. Soon others are being killed and posed in bizarre ways that suggest a link to early martyrs.
Lots of fascinating detail about Rome, Italian customs and how to flay a body. There is a rather gross description of just how to do it (might take about an hour and requires lots of anatomical knowledge and strength) not to mention a reference to some cultures that tried to do it while the victims remained alive. And by the way, now that I have your attention, some Italians enjoy eating offal, prepared in all sorts of garlicy ways. This is apparently from the days when the clergy got all the good parts and the rest were thrown to the proletariat who discovered ways to make it more than palatable. There is a nifty (hmm, perhaps bad choice of words) scene where Costa is invited to dinner with the brilliant pathologist, "crazy" Theresa, and they eat at one of these restaurants. Costa is a vegetarian.
I liked this book, but it does seem that some of the tantalizing leads, for example the "seed of the church" comment above that appears to be significant early on, never gets linked to anything later on. Lots of neat conspiracy stuff. While the inter-connectivity of some of the characters might stretch one's credibility, the shades of gray in the characterizations are what I found most intriguing about the book.
Caravaggio's paintings play an important role that I enjoyed. This is probably the book that Dan Brown wishes he could have written. Of other Italian location writers, I would place him closest to Michael Dibdin, if perhaps not quite as intellectual.
Note: David Hewson has novelized the Danish series "The Killing" which has received excellent reviews. I will be reading it, having been addicted to the American remake of the Danish that takes place in Seattle.