the Ustaše massacred about thirty of the village's inhabitants, mostly the elderly and infirm, who had been unable to flee along with the others. Concurrently, Luburić and his followers massacred the inhabitants of the nearby village of Bubanj. According to their own internal documents, the Ustaše killed 152 Serb civilians in Bubanj, and burned down twenty homes. In some households, not a single person was left alive. Survivor accounts suggest that the number of fatalities was about 270. On 3 July, one of Luburić's units detained 53 inhabitants of the village of Nebljusi, including ten children under the age of 12. They were transported by horse-drawn cart to the nearby village of Boričevac, which contained a barracks and a karst pit. The residents of Nebljusi were detained inside the barracks until nightfall, alongside twelve adult males who had been arrested earlier. That evening, they were marched to the karst pit in groups of eight and pushed inside to their deaths. Two of the victims managed to survive the ordeal. By the end of July, the Ustaše had killed at least 1,800 Serbs in and around Lika. The Ustaše atrocities against the NDH's Serb population prompted thousands of Serbs to join Josip Broz Tito's Partisans and Draža Mihailović's Chetniks. The Lika massacres in particular served as the casus belli for the Srb uprising, which commenced on 27 July. The revolt led to the Italian military occupations of Zone II and Zone III. "Luburić and his superiors had wrongly calculated that the brutal killings of an innocent population would quash any embryonic resistance to their plan for the creation of an 'ethnically pure area'," Goldstein remarked. "Their actions ... provoked the completely opposite effect." In mid-July 1941, Luburić was tasked with recapturing dozens of inmates who had escaped from the Kerestinec camp. Almost all the fugitives were captured or killed, and several Ustaše also lost their lives. Ustaše Surveillance Service, Bureau III Jasenovac, I–III The NDH's security sector was made up of two agencies, the Directorate for Security and Public Order (; RAVSIGUR) and the Ustaše Surveillance Service (; UNS). Both the RAVSIGUR and the UNS were led by Kvaternik's son, Dido. The RAVSIGUR was established on 4 May 1941. The UNS was established in August. The latter was divided into three bureaus: Bureau I, Bureau III and Bureau IV. Bureau III, also known as the Ustaše Defense, was tasked with administering