The use of gas vans by the Germans to murder Jews, Poles, Romani people, mentally ill people, and prisoners in occupied territories during World War II originated with the Nazi Euthanasia Program in 1939. Ordered to find a suitable method of killing, the "Technical Institute for the Detection of Crime" ("Kriminaltechnisches Institut der Sicherheitspolizei", abbreviated KTI) of the Reichssicherheitshauptamt (RSHA) decided to gas victims with Carbon monoxide. In October 1939 the Nazis started gassing prisoners in Fort VII near Posen. The first victims were Polish and Jewish inmates of asylums for the mentally ill. Witnesses report that since December 1939, mobile gas chambers were used to kill the inmates of asylums in Pomerania, Eastern Prussia and Poland. The vans were built for the Sonderkommando Lange and their use was supposed to speed up the killings. Instead of transporting the victims to the gas chambers, the gas chambers were transported to the victims. They were most likely devised by specialists from the Referat II D of the RSHA. These mobile gas chambers worked under the same principles as the stationary gas chambers: through a rubber hose the driver released pure CO from steel cylinders into the air tight special construction that was shaped like a box and placed on the carrier. The vans resembled moving vans or delivery lorries and they were labelled "Kaiser’s Kaffee Geschäft" () (“Kaiser's Coffee Shop”) for camouflage. They were not called "gas vans" at the time, but “Sonder-Wagen”, “Spezialwagen” (special vans) and “Entlausungswagen” (delousing vans). The Lange commando killed patients in numerous hospitals in the Wartheland in 1940. They drove to the hospitals, collected patients, loaded them into the vans and gassed them while they were driving them away. From 21 May to 8 June 1940 the Sonderkommando Lange killed 1558 sick people from Soldau concentration camp alone.