A Death in Cornwall by Daniel Silva

 This is the latest Gabriel Allon adventure. A professor is found dead in Cornwall. She had been investigating the provenance of a Picasso that originally belonged to a man who died during the Holocaust. Timothy Peel, whom Gabriel met when he was a young boy, is now a policeman in Cornwall. He calls Gabriel asking for help (under the radar) on the case. Gabriel and his computer expert friend Ingrid uncover a massive art/tax fraud scheme that almost overturns a government and nearly costs Gabriel and Ingrid their lives. It's a compelling story that puts Gabriel's two skill sets--spy and art restorer --to good use.