"Sonderkommando" members did not participate directly in killing; that responsibility was reserved for the SS, while the "Sonderkommandos" primary duty was disposing of the corpses. In most cases, they were inducted immediately upon arrival at the camp and forced into the position under threat of death. They were not given any advance notice of the tasks they would have to perform. To their horror, sometimes the "Sonderkommando" inductees would discover members of their own family amid the bodies. They had no way to refuse or resign other than by committing suicide. In some places and environments, the "Sonderkommandos" might be euphemistically called "Arbeitsjuden" (Jews for work). Other times, "Sonderkommandos" were called "Hilflinge" (helpers). At Birkenau the "Sonderkommandos" numbered up to 400 people by 1943 and, when Hungarian Jews were deported there in 1944, their numbers swelled to more than 900 persons, in order to keep up with the increased rounds of murder and extermination.