Officials in the »Chancellery of the Führer« headed by Viktor Brack put Hitler's »euthanasia« authorisation into action by developing a killing machine. In the administrative headquarters in Berlin and in the killing stations, about 500 people were directly involved in the organisation and the smooth running of »Aktion T4«. The judiciary covered up the campaign of murders.

»What was behind this was: to help the man who cannot help himself and who is eking out an existence with appropriate agonizing suffering,« said Karl Brandt in the Doctors' Trial in 1947. Many doctors cooperated out of personal careerism, authoritarian thinking or inner conviction. For them, healing and annihilation belonged together. As medical experts, they selected the victims. In the T4 institutions, they turned on the gas tap. In the hospitals, doctors murdered with drugs or let the inhabitants starve to death. They conducted experiments on patients doomed to die or research on the brains of the murdered.

Male and female nurses helped the medical staff to carry out the murders using gas. They killed with injections or tablets.