The first camp commander of Sobibor was the Austrian SS Obersturmbannführer (lieutenant colonel of an assault unit) Franz Stangl. Stangl had already built his reputation in Austria as the supervisory head of the T-4 Euthanasia Programme in Hartheim (near Linz). In Hartheim the Nazis carried out large-scale murder of mentally and physically handicapped people. Later on Stangl said that he saw the mass murder of Jews as his 'profession' and that he 'enjoyed it'. In September 1942, Stangl was transferred to Treblinka to 'set matters in order' and to have the camp run like a well-oiled machine. Stangl's right-hand man in Sobibor was Gustav Wagner, who remained in this post when Franz Reichleitner was appointed commander of Sobibor (in September 1942). The camp was run by a small German SS unit (between 20 and 30 men) and between 90 and 120 'Trawniki', prisoners of war from various nationalities who were specifically selected for this work. Most of the Trawniki in Sobibor were former Ukrainian soldiers. The dirtiest work was done by Jewish slave labourers.