Sisak children's concentration camp was founded on 3 August 1942 following the Kozara Offensive. It was part of an assembly camp, officially named the "Refugee Transit Camp". This concentration camp consisted of a special part officially called the "Shelter for the Refugee Children" under the auspices of the "Ustasha Female Lineage" and "Ustasha Security Service", and under the direct control of Antun Najžer. The camp was located in several buildings in Sisak: the former Yugoslav Falconry Association ("Sokolana"), the Sisters of St. Vincent nunnery, a rice warehouse, Rajs Saltworks warehouse, Novi Sisak elementary school, and the "Karantena" (Quarantine). All these buildings were considered unsuitable for the housing of children. For example, in the Falconry Association, there were no doors; it was drafty because it was built for drying salt. Children, even those who were only a few months old, had to lie on the floor with only a thin layer of straw without any clothes or blankets. When a typhus epidemic broke out, Najžer ordered the transfer of the infected children to an improvised hospital, only serving to increase the number of deaths.