Chełmno concentration camp Laabs was ordered to the Chełmno concentration camp where he served between April 1942 and January 1945, and started driving the
gas wagon within a few days of his arrival. When Laabs went to the
Gestapo headquarters in Posen, he was informed that he would start working at a
Sonderkommando in Chełmno. The next day, he met
Walter Burmeister, who drove him and another
SS-man, Oskar Hering, to Chełmno. The camp, located in
Chełmno nad Nerem, consisted of an old manor building and an area of about 3–4 kilometres of woods to the northwest of the manor building. In later court hearings, Laabs spoke about how the gassings were done. He drove the gas wagon alongside the manor building and about fifty Jews were brought into the wagon at a time. When it was full, the back door was locked. Heydrich was murdered a few months later and the plans were halted. The following year
Reichsführer-SS Heinrich Himmler gave orders that all mass graves in Poland and the Soviet Union be demolished, leaving no traces of the mass murder. Blobel's work started in Chełmno, where they tried to destroy the
exhumed bodies in fire bombings, this method proved ineffective and Blobel decided to burn the bodies on iron bars in a large fire. Laabs told a later court hearing that the camp managers ordered a machine to grind down the bones following the burning. The ashes of the bodies were poured into the
Ner river. The area of the mass graves was destroyed and new trees were planted. ==Chełmno trials and criminal conviction==