From November 1944 to mid-1947, during the period of armed anti-communist insurgency against the Soviet takeover of Poland, many Jews who were part of communist groups were killed by the National Armed Forces. In Warsaw, the National Armed Forces killed Jerzy Makowiecki and Ludwik Widerszal, two Polish Home Army officers of Jewish origin. Polish historian Alina Cała said that the doctrine of the National Armed Forces was primarily the elimination of what they considered to be Communist bands. According to sociologist Tadeusz Piotrowski, these attacks later "became more focused on individual Jews who were placed in highly visible positions of authority in the PRL Republic of Poland".