It depends on one's understanding of the word 'crime'. After taking power the National Socialists passed various laws; thus almost everything that was done by the Nazis (and thus directly or indirectly by Hitler) was perfectly legal. If something is permissable in law then it is not a crime and so such things as euthanising the mentally challenged, forbidding Jewish doctors to treat non-Jews, forbidding Jewish-non Jewish marriage, sending people to the ghetto were perfectly legal and technically not crimes.
One of the problems with placing Nazis on trial after the War for 'crimes against humanity' was that there was no such thing as the UN's Universal Declaration of Human Rights when the Third Reich existed. Thus, the Nazis could claim that the courts had no jurisdiction or authority and that no crimes had been committed. Properly speaking, they were correct though, on a moral level, people found the actions of the Nazis to be abhorrent.
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http://wiki.answers.com/Q/What_crime...#ixzz1Q1Pat0t9