The Ustashi was the only group written up for brutality to prisoners. By the SS. Twice.
Interesting, I was just reading about this Catholic Priest that was a Commandant @ the Nazi Concentration Camp, Jasenovac in Yugoslavia where as many as 7,000,000 were murdered, mostly Serbian Christians. More info here on Jasenovac, Croatia’s Nazi links, etc. here: http://emperors-clothes.com/