The Exception by Christian Jungersen

Iben, Malene, Anne-Lise, and Camilla all work for the Danish Center for Information on Genocide (DCIG) in Copenhagen. It's a small organization, with only one other employee, the director, Paul. When Iben and Malene, who are best friends, receive e-mail death threats, the office relationships become tense. Iben and Malene believe that Serbian war criminal Mirko Zigic is responsible. But soon, the women suspect each other. By interspersing accounts of genocide among the points of view of three of the co-workers, Jungersen creates a novel where the reader isn't sure who is telling the truth. When there is a death of someone close to the women, things get even more unhinged. Who will be unmasked as the culprit? The Exception is very similar to the recent mysteries of Minette Walters.