a sub-camp dedicated to leather production, which became known as the Tannery (). A fifth and final sub-camp, Jasenovac V, was established around the same time. Known as Stara Gradiška, after the village in which it was located, it was overseen by both male and female guards. Among them were Luburić's half-sisters, Nada and Zora. The former participated extensively in the tortures and executions that took place at Stara Gradiška. She went on to marry Dinko Šakić. During the war, Šakić served as the deputy commander of Stara Gradiška, and later, as the commander of the Brickyard. Luburić also recruited his cousin Ljubo Miloš. Miloš served as the labour service commandant at the Brickyard. Like Luburić, who was in his late twenties when he was appointed head of Bureau III, most of the Ustaše tasked with administering the Jasenovac camp system were extremely young. Šakić was 20 in 1941 and Miloš was 22. The Jasenovac camp system was guarded by more than 1,500 Ustaše. The Brickyard, the Tannery and Stara Gradiška were capable of holding 7,000 inmates, although the number of inmates never exceeded 4,000 at any given time. Luburić visited the Jasenovac camp system two or three times per month. He insisted on personally killing at least one inmate on each of his visits. Luburić enjoyed taunting prisoners as to the date and method of their execution. He would "amuse himself by placing his revolver up against the heads of the prisoners," the Tito biographer Jasper Godwin Ridley writes. "Sometimes he pulled the trigger; sometimes he did not." Luburić's cruelty also extended to the other Ustaše camps. In one instance, he deliberately dispatched hundreds of typhus-ridden inmates from Stara Gradiška to Đakovo so as to expedite the spread of the disease among its prisoners. "Luburić created such an atmosphere," Miloš recalled, "that every Ustaša actually felt himself called upon to kill a prisoner, believing that this would be an act of patriotism." After unsuccessfully experimenting with gas vans, Luburić ordered that a gas chamber be constructed at Stara Gradiška, which used a combination of sulfur dioxide and Zyklon B. The gas chamber was poorly constructed and this method of killing was abandoned after three months. Over the course of the war, unlike in the German camps, most inmates were killed with knives or blunt objects. In early 1942, conditions at Jasenovac improved somewhat in anticipation of a visit by