In October of 1939 amid the turmoil of the outbreak of war Hitler ordered widespread "mercy killing" of the sick and disabled.
Code named "Aktion T 4," the Nazi euthanasia program to eliminate "life unworthy of life" at first focused on newborns and very young children. Midwives and doctors were required to register children up to age three who showed symptoms of mental retardation, physical deformity, or other symptoms included on a questionnaire from the Reich Health Ministry.
A decision on whether to allow the child to live was then made by three medical experts solely on the basis of the questionnaire, without any examination and without reading any medical records.
Each expert placed a + mark in red pencil or - mark in blue pencil under the term "treatment" on a special form. A red plus mark meant a decision to kill the child. A blue minus sign meant a decision against killing. Three plus symbols resulted in a euthanasia warrant being issued and the transfer of the child to a 'Children's Specialty Department' for death by injection or gradual starvation.
The decision had to be unanimous. In cases where the decision was not unanimous the child was kept under observation and another attempt would be made to get a unanimous decision.
The Nazi euthanasia program quickly expanded to include older disabled children and adults. Hitler's decree of October, 1939, typed on his personal stationary, enlarged "the authority of certain physicians to be designated by name in such manner that persons who, according to human judgment, are incurable can, upon a most careful diagnosis of their condition of sickness, be accorded a mercy death."
Questionnaires were then distributed to mental institutions, hospitals and other institutions caring for the chronically ill.
Patients had to be reported if they suffered from schizophrenia, epilepsy, senile disorders, therapy resistant paralysis and syphilitic diseases, retardation, encephalitis, Huntington's chorea and other neurological conditions, also those who had been continuously in institutions for at least 5 years, or were criminally insane, or did not posses German citizenship or were not of German or related blood, including Jews, Negroes, and Gypsies.
A total of six killing centers were established including the well known psychiatric clinic at Hadamar. The euthanasia program was eventually headed by an SS man named Christian Wirth, a notorious brute with the nickname 'the savage Christian.'
At Brandenburg, a former prison was converted into a killing center where the first Nazi experimental gassings took place. The gas chambers were disguised as shower rooms, but were actually hermetically sealed chambers connected by pipes to cylinders of carbon monoxide. Patients were generally drugged before being led naked into the gas chamber. Each killing center included a crematorium where the bodies were taken for disposal. Families were then falsely told the cause of death was medical such as heart failure or pneumonia.