High Quality Content by WIKIPEDIA articles! Action 14f13, also called "Sonderbehandlung ("special treatment") 14f13", was a campaign of the Third Reich to murder Nazi concentration camp prisoners. Also called "invalid" or "prisoner euthanasia", the campaign culled the sick, elderly and those deemed no longer fit for work from the rest of the prisoners in a selektion, after which, they were killed. The Nazi campaign was in operation from 1941–1944 and later covered other groups of concentration camp prisoners, as well.