Most »euthanasia« trails took place in the early years after the end of the war. It was mainly the courts of the Allies that handed out the death sentence for murder between 1945 and 1947. The male nurses Karl Willig and Heinrich Ruoff (1887–1946) as well as the administrative manager of Hadamar, Alfons Klein (1909–1946), nurse Helene Wieczorek (1904–1947) and Dr Hilde Wernicke (1899–1947) from Meseritz-Obrawalde, as well as the medical director of T4 Paul Hermann Nitsche and Karl Erhard Gäbler (1888–1948), a male nurse in the Sonnenstein killing centre, were executed. The judges in the Doctors' Trial in Nuremberg in 1947 also sentenced to death Karl Brandt and Viktor Brack, the main people in charge of the »euthanasia« murders.
After 1949, criminal proceedings took place less often and the sentences passed were markedly milder. If the courts had previously regarded the facts of the case as indicating murder, they later assumed manslaughter. They conceded that the perpetrators had been ignorant of the illegality of their actions. The judges regarded the »destruction of life unworthy of life« not fundamentally »immoral« – which is why perpetrators such as Werner Catel never stood trial in 1949.
Other trials in the 1960s – largely driven by Attorney General of Hesse Fritz Bauer – mostly ended in no sentence being passed. Assessors certified that T4 perpetrators such as Georg Renno were unfit to attend trial.