I have a friend from Bosnia. Yes, Muslim (secular) but the men in her family drink like fishes and seem to all be 10 feet tall.
Anyway, she told me the horrific story of how her father was murdered (along with several dozen other men and boys) by a group led by his former business partner. Yes, business partner. Them men were tortured, then placed in tanker, machine gunned, then it was set on fire.
Evidently, those folks over in the Balkans have long memories and the hate just burned its way up to the surface. Civil wars are nasty affairs.