They killed, looted, tortured, terrorized, sacked, annihilated, destroyed, humiliated, degraded, exterminated, etc.

Evil

genocide, ethnic cleansing, human experimentation, torture - I dare say there are others too.

War crime, war criminal, slaughter, genocide....etc

Holocaust Noun: holocaust - /ˈhɑləˌkɔst/ ♫ 1. An act of mass destruction and loss of life (especially in war or by fire). A nuclear holocaust. 2. [Holocaust] The mass murder of Jews under the German Nazi regime from 1941 until 1945.