An "SS-Sonderkommando" unit led by "SS-Sturmbannführer" Herbert Lange murdered 1,201 psychiatric patients at the Tiegenhof psychiatric hospital in the Free City of Danzig, 1,100 patients in Owińska, 2,750 patients at Kościan, and 1,558 patients at Działdowo, as well as hundreds of Poles at Fort VII, where the mobile gas van and gassing bunker were developed. In 1941–42, "SS-Sonderkommando Lange" set up and managed the first extermination camp, at Chełmno, where 152,000 Jews were killed using gas vans.