Proscription lists ( '' Sonderfahndungsbuch Polen '' ) , prepared before the war started , identified more than 61,000 Polish elite and intelligentsia leaders deemed as unfriendly towards Germany . Already during the 1939 German invasion , dedicated units of SS and police ( the '' Einsatzgruppen '' ) were tasked with arresting or outright killing of those resisting the Germans . They were aided by some regular German army units and " self-defense " forces composed of members of German minority in Poland , the Volksdeutsche . The Nazi regime 's policy of murdering or suppressing the ethnic Polish elites was known as Operation Tannenberg . This included not only those resisting actively , but also those simply capable of doing so by the virtue of their social status . As a result , tens of thousands of people found " guilty " of being educated ( members of the intelligentsia , from clergymen to government officials , doctors , teachers and journalists ) or wealthy ( landowners , business owners , and so on ) were either executed on spot , sometimes in mass executions , or imprisoned , some destined for the concentration camps . Some of the mass executions were reprisal actions for actions of the Polish resistance , with German officials adhering to the collective guilt principle and holding entire communities responsible for the actions of unidentified perpetrators
Operation Tannenberg
Operation Tannenberg
Occupation of Poland (1939–1945)