factories were built secretly in east-central Poland. The SS officers responsible for the earlier Aktion T4, including Wirth, Stangl and IrmfriedEberl, had important roles in the implementation of the "Final Solution" for the next two years.[93][n] The first killing centre equipped with stationary gas chambers modelled on technology developed under Aktion T4 was established at Bełżec in the General and people care) in the Ministry of the Interior. In 1939, he became assistant director; Cropp was involved in the Nazi "euthanasia" Aktion T4 in 1940. He was Herbert Linden's superior and was responsible for patient transfers.[129] * IrmfriedEberl captured 1948; committed suicide to avoid trial. * Gottfried von Erdmannsdorff, commander of Fortress Mogilev, where many physically and mentally disabled