Turncoat — Aaron Elkins

Pete Simon's All-American life fell apart in the days following the assassination of John F. Kennedy...

It begins with the appearance of a stranger at his door--an unwelcome visitor ranting madly about money, death, and forgiveness; a man known all too well to Pete's distraught wife, Lily: her father. The next day the man is dead--and Lily disappears, leaving a note behind begging Pete not to follow. Now, with a business card from an antiques dealer in Barcelona as his only lead, Pete Simon embarks on a twisted and perilous journey that will carry him to places where the hideous crimes of the Nazi aggressors remain fresh in the minds of those who cannot forget . . . or forgive. But each door he opens leads him deeper into a painful and shocking past. And suddenly an ordinary American has become more than a concerned husband and seeker of a bit-ter truth; he has become the target of desperate, dangerous men and their terrifying vengeance.