Klavan, Andrew. Cameron Winter mystery

"Cameron Winter is troubled in heart and mind. He's plagued by memories of his time as a government operative investigating a notorious Turkish sex trafficker. The fact that the mission was left unfinished still haunts him and threatens to tear him apart. In the midst of his painful soul-searching, Winter crosses paths with an ex-flame--his first love--and the chance encounter ignites a passion he thought was long lost. But just as soon as she wanders back into Winter's life, the woman vanishes, leaving Winter scrambling to track her down. His pursuit takes him deep into a world rent by partisan violence, where extremists clash and Winter sides with no one. As he faces his most dangerous case yet, victory might simply mean getting out alive"--