Bishop Clemens August von Galen (1878–1946) openly denounced the »euthanasia« murders in a sermon early in August 1941. Copies of this sermon spread throughout the German Reich, causing an uproar. Due to Galen's popularity, the regime did not want to take action against him.

Pastor Paul Gerhard Braune (1887–1954) headed the Hoffnungstal Institutions near Bernau, where he initially prevented deportations by the T4 organisation. He researched the backgrounds of the operation and sent the results to Adolf Hitler and Hermann Goering in the form of a memorandum in July 1940. As a result, he spent three months in custody. The secrecy surrounding the »euthanasia« murders prevented any trial and so led to his release.