Brimstone by Douglas Preston and Lincoln Child

Agent Pendergast returns in a new suspense thriller from New York Times bestselling authors Douglas Preston and Lincoln Child. Art critic Jeremy Grove is found dead, his face frozen in a mask of terror. His body temperature is grotesquely high; he is discovered in a room barricaded from the inside; the smell of brimstone is everywhere....and the unmistakable imprint of a claw is burned into the wall. As more bodies are discovered-their only connection the bizarre but identical manner of death-the world begins to wonder if the Devil has, in fact, come to collect his due. Teaming with Police Officer Vincent D'Agosta (The Relic), Agent Pendergast is determined to solve this case that appears to defy everything except supernatural logic. Their investigation takes them from the luxury estates of Long Island to the crumbling, legend-shrouded castles of the Italian countryside, where Pendergast faces the most treacherous and dangerous adversary of his career.

 I've read 3 Pendergast books so far and I didn't enjoy this one as much as the first two...I'm going to read the other two books in the series and see if it gets better. Two Pendergasts could be really challenging, one good, one evil.....