The Nearest Exit

Description for THE NEAREST EXIT by Olen Steinhauer:

Faced with the potential dissolution of his marriage and the end of his quiet, settled life, reluctant spy Milo Weaver has no choice but to return to his old job as a "tourist" for the CIA. But before he can get back to the dirty work of espionage, he has to prove his worth to his new bosses. Armed with a stack of false identities, Milo heads back to Europe, and for nearly three months every assignment is executed perfectly. Then he's instructed to kill the fifteen-year-old daughter of Moldovan immigrants, and make the body disappear. No questions. For Milo, it's an impossible task, but ignoring his handlers is equally untenable. Suddenly he's in a dangerous position, caught between right and wrong, between powerful self-interested foes, between patriots and traitors -- especially now that he has nothing left to lose...

this is #2 in Milo Weaver Series.