Simon Weisenthal made the arresting observation that the worst (and capital) Nazi crimes were 
 committed in Poland, not in Germany. The Polish Government-in-Exile was well aware of the 
 circumstantial evidence pointing towards mass extermination of Jews and others on Polish 
 soil in specially designed deathcamps (not hard-labor internment camps.) This was clearly 
 a gross violation of pre-existing Polish law against kidnapping and homicide. The Polish 
 government in exile in London issued a white paper to the United Nations (the Atlantic 
 Alliance) that they intended to prosecute the Nazi miscreants for these criminal deeds. 
 And the Poles were a force to be reckoned with. They supplied an air force that managed 
 to escape to England. They supplied pilots that gave the margin of victory in the Battle 
 of Britain. They supplied the stolen specimen of the Enigma cipher machine. They supplied 
 the infantry to overrun the fortress atop Monte Cassino. They eliminated collaborationists. 
 They even liberated one of the deathcamps (the so-called Goose camp in Warsaw) using a stolen 
 Panzer tank. The Poles had a legitimate and functioning government that indicted the 
 Nazi invaders for their numerous capital crimes in Poland. It was not "ex post facto" law 
 by any stretch of the imagination!