I've read about a few German concentration camps in WWII and have a relative who was an American POW in Germany. As the Allies got closer to Germany towards the end of the war, the Germans moved POWs and people in at least some concentration camps further into Germany. This was at a time when Germany was struggling to keep fighting, food was scarce, POWs and people in concentration camps were already weak from hunger and the bitterly cold winter of 1945. I can kind of understand moving the POWs to prevent then from being liberated by the Allies and potentially coming back to fight Germany. But I don't understand the strategic advantage of moving starving people away from the Allies as the Allies got closer. Does anyone know why this was done?
The way Germany dealt with KZ inmates was often highly contradictory. The first reason to evacuate the camps was to destroy evidence before the allied forces arrived. When Auschwitz was evacuated in January 1945, tens of thousands of inmates were moved - the SS simply couldn't kill them all.
Another, contrary reason is that Himmler used Jewish inmates as pawn for his negotiations with the allies. Sometimes, KZ prisoners were sold for trucks and fuel. Very late in the war, 100s of Scandinavian prisoners from KZs Mauthausen and Melk were freed and transported north in buses by the red cross.
In the end, the KZ system was carried on, but out in the open, during these transports and death marches to the inner parts of the Reich. While hierarchies and communications broke down, camp commanders and SS guards often killed at will. The later the evacuations started, the more haphazard these transports and death marches became.
Sick prisoners were killed, often by injections to the heart and/or strangling, the rest were sent on their way. In many instances, local NS officials and even units of the Volkssturm and Hitler Youth conducted massacres among the prisoners, as on Präbichl or in Hofamt Priel, just hours and days before the liberation.