 Thus Himmler knew another method of mass killing was required.After the war, the diary of the Auschwitz Commandant, Rudolf Höss, revealed that psychologically "unable to endure wading through blood any longer", many "Einsatzkommandos" – the killers – either went mad or killed themselves.The Nazis had first used gassing with carbon monoxide cylinders to kill 70,000 disabled people in Germany in what they called a 'euthanasia programme' to disguise that mass murder was taking place.