The National Socialist regime started to prepare for a campaign of murder of institutional patients allegedly unworthy of life in the German Reich in 1939. The »Chancellery of the Führer«, directly subordinate to Adolf Hitler (1889–1945), was responsible for organising it. The Ministry of the Interior of the German Reich and the state authorities were involved in its implementation.

Starting with the »Chancellery of the Führer« under Philipp Bouhler, doctors and administrative staff at Tiergartenstrasse 4 organised the detection and selection of inpatients. They coordinated the patients' transportation to the killing centres distributed across the German Reich. A large administrative apparatus was intended to ensure the smooth running and the secrecy of the mass murders. After »Aktion T4« was called off, the headquarters tried to bring the drug killings under their control, and continued the recording of patients by means of the registration forms.

The perpetrators made use of a bureaucratic, dehumanizing style of language in their work. They used terms such as »disinfected« and »attended to« to refer to the killing of the patients. The victims were thus degraded to mere objects and their murder was dealt with as a purely administrative act.