The killing of children with disabilities began in the autumn of 1939, soon extending to adults, many of whom were ferried away in now-infamous grey buses to disguised gassing centres. As many as 300,000 died in the programme during WWII.
Rumours of the killings soon began to circulate, prompting families to remove their relatives from asylums, fearing for their safety. Professor Hans Gerhard Creutzfeldt was able to save his patients by re-diagnosing them, thus preventing them from being sent to the killing centres, although he was an unusual case.
Lothar Kreyssig was a judge in a mental health guardianship court near Berlin, meaning he was responsible for hundreds of children and adults with disabilities. Kreyssig publicly criticised T-4, and reportedly threatened to instigate murder charges against the officials responsible. Already a figure of suspicion for his refusal to join the Nazi Party, he was forced to resign for his actions.
There were protests from parents, including Anna Wödl, an Austrian nurse and mother of Alfred, a child with speaking and walking difficulties. Aware that her child was at risk, Wödl led a small protest movement and encouraged the relatives of children at Am Spiegelgrund, a child euthanasia centre in Vienna, to send protest letters to high-ranking officials. Alfred was killed in 1941.
Perhaps the most notable grassroots protest arose in early 1941, in Absberg, Bavaria. When the grey buses arrived, local people with disabilities resisted the round up, and horrified villagers formed crowds and temporarily blocked the buses. The people of Absberg later contacted the Catholic Bishop Clemens August Count Von Galen, who slammed the programme from his pulpit on 3 August 1941, leading to the official cancellation of the programme shortly after. However, despite the official ending, the killings continued in a more clandestine and decentralised manner until the end of the war.