The Secret Servant by Daniel Silva
In Amsterdam, an Israeli terrorist analyst is murdered. The police believe the killer is a deranged Muslim extremist, but Israeli intelligence knows better. Art-restorer, assassin and spy Gabriel Allon is dispatched to investigate, uncovering a major terrorist operation in London.
Gabriel arrives too late to prevent the kidnapping of the daughter of the US ambassador. With time running out, Allon has no choice but to plunge into a desperate search, both for the woman and for those responsible, but the truth, when he finds it, is more terrible than he could expect. It will endanger his life and shake him to the core.