[1] As an operator of a gas van, Laabs was directly involved in the genocidal extermination of over 100,000 men, women and children, most of whom were Jewish.

[1] 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.

[5] The next day, SS-man Erwin Bürstinger, who was responsible for the vehicles, showed Laabs and Hering the camp and told them to test drive the gas wagons.

[5] In early 1942, Standartenführer Paul Blobel was ordered by Reinhard Heydrich to lead the Sonderaktion 1005, which was tasked with digging up the mass graves to burn the corpses.

Laabs told a later court hearing that the camp managers ordered a machine to grind down the bones following the burning.

[1] At the end of November 1963, Laabs and ten other people from the Chełmno concentration camp were tried at the Landgericht Bonn [de] regional court.