The following is fiction, from Chapter 23 of "A Grave Breach" (May 2005) which has elements of the Bosnian war as a background and at one point, there's this about people such as the man in this article.
"In many other cases, the victimizers who were not caught in a web of reprisal moved on, back to their homes, perhaps, where their own families may or may not have been waiting; where they looked at their wives and their sons and their daughters and saw the faces of their own victims and wondered how in God’s name they had become, even for a time, what they had become. And done what they had done. Back in their places of personal refuge, they learned to their horror that, for them, the veneer of civilization was an internal construct, not an external restraint. And they came face to face with the realization that, while there would never be forgiveness from their victims, their true punishment was that they could never forgive themselves."
Pretty powerful writing, Jim. You have to ponder not just how people who do these kinds of things live with themselves afterward, but how they manage to justify it in their own minds at the point when they actually walk into a room filled with prisoners, point their weapon at an unarmed and helpless human being and pull the trigger. I'll be looking for the book.