Auschwitz concentration camp was emptied of its internees, as the Red army advanced from the east, in January 1945 and Axen was among the survivors transferred to Buchenwald near Weimar. Sources assert that he was a member of the illegal Communist Party leadership team in the concentration camp. As the war neared its end, in April 1945 it was US troops that liberated Axen from the Buchenwald camp.