Adolf Hitler Implements the Nacht und Nebel Directive

Nacht und Nebel (German for "Night and Fog") was a directive (German: Erlass) of Adolf Hitler on 7 December 1941 signed and implemented by Armed Forces High Command Chief Wilhelm Keitel, resulting in kidnapping and forced disappearance of many political activists and resistance 'helpers' throughout Nazi Germany's occupied territories, principally in Western Europe. Anyone guilty of endangering the "security or state of readiness" of German forces and who was not to be summarily executed simply vanished into the "night and fog" of Germany. It was a specific punishment for opponents of the Nazis in occupied countries and intended to intimidate local populations into submission by denying families and friends of "les disparus" all knowledge of what had happened to them. To this day, it is not known how many people were seized as a result of this order.

http://en.wikipedia.org/wiki/Night_and_Fog_Decree