Articles related to Aktion T4, a campaign of mass murder by involuntary euthanasia which targeted people with disabilities in Nazi Germany. The term was first used in post-war trials against doctors who had been involved in the killings. The killings took place from September 1939 until the end of World War II in Europe in 1945; from 275,000 to 300,000 people were killed in psychiatric hospitals in Germany and Austria, occupied Poland and the Protectorate of Bohemia and Moravia (now the Czech Republic).