Stara Gradiška concentration camp Stara Gradiška was one of the most notorious concentration and extermination camp s in Croatia during World War II , mainly due to the crimes which were committed there against women and children . The camp was specially constructed for women and children of Serb , Jew , and Romani ethnicity . It was established by the Ustaše ( Ustasha ) regime of the Independent State of Croatia ( " NDH " ) in 1941 at the Stara Gradiška prison near the village of Stara Gradiška . as the fifth subcamp of the Jasenovac concentration camp According to the list of victims by name of KCL Jasenovac , the Jasenovac memorial site , which includes research , the names and data for 12 , 790 victims of the camp have been established . Systematic killing of inmates . The camp was guarded by the Germans ' allies , the Croatian Ustaše and a few female Croatian troops . Inmates were killed using different means , including firearms , mallets and knives . At the " K " or " Kula " unit , Serbian and Jewish women , with weak or little children , were either starved and tortured at the " Gagro Hotel " , a cellar in which Ustaša Nikola Gagro used as a place of torture . Other inmates in the Kula unit were poisoned with gas . Gas experiments were conducted initially at veterinary stables near the " Economy " unit , where horses and then humans were poisoned using sulphur dioxide and later Zyklon B . Gassing was also tested on children in the yard , where the camp commandant , Ustaša sergeant Ante Vrban , viewed its effects . Most gassing deaths occurred in the attics of " the infamous tower " , where several thousand children from the Kozara region were killed in May , and 2000 more in June 1942 . Subsequently , smaller groups of 400 - 600 children , and a few men and women , were gassed . At this trial , Vrban stated : Witness Cijordana Friedlender testified : " At that time fresh women and children came daily to the Camp at Stara Gradiška . About fourteen days later , Vrban [ the Commandant of the Camp ] ordered all children to be separated from their mothers and put into one room . Ten of us were told to carry them there in blankets . The children crawled about the room , and one child put an arm and leg through the doorway , so that the door could not be closed . Vrban shouted : ' Push it ! ' When I did not do that , he banged the door and crushed the child ' s leg . Then he took the child by its whole - leg , and banged it on the wall until it was dead . After that we continued carrying the children in . When the room was full , Vrban brought poison gas and killed them all . " According to witness Milka Zabičić , the gassing stopped due to a scheduled visit by a Red Cross delegation in 1943 , which did not arrive until June 1944 . Gas - vans were constructed to kill Serb and Jewish women and children who came to Stara Gradiška from the Đakovo camp in June – July 1942 . Witness Dr . Dragutin Skgratić confirmed : " He ( Šakić ) directed his guards to pack women and children into the vans , fitted a rubber hose from the exhaust to the interior and drove around and around the camp until the passengers were dead , ' They killed at least half the group like this as soon as they arrived ' . " Cruelty . Stara Gradiška became notorious for crimes committed against women and children . Examples included the torture that took place in cellar 3 , the " Gagro Hotel " , where inmates were starved , tortured and then strangled to death using piano wire . In Šakić ' s trial , witness Ivo Senjanović recalled how people were locked there without food or water : " The people were gradually dying . It was horrible to hear them cry for help . " As for the conditions , witness Cadik Danon said : Several criminals stood out , including Nikola Gagro , Antun Vrban , Nada Luburić , Maja Buzdon , Jozo Stojčić and , notably , the commander and former - friar Miroslav Filipović - Majstorović , who killed scores of women and children with his bare hands . The treatment of inmates was so horrific that on the night of 29 August 1942 , bets were made among the prison guards as to who could liquidate the largest number of inmates . Petar Brzica , one of the guards reportedly cut the throats of 1 , 360 prisoners with a butcher knife . A gold watch , a silver service , a roasted suckling pig , and wine were among his rewards . The men guards had female guards ( who were sisters or wives of the guards ) were known for their cruelty . The most notable guard was , the sister of the first commandant of Jasenovac , guard Maks Luburić and wife of Dinko Sakic ( hence she was Nada Sakic ) . Clearing the camp . In early April 1945 , when the Partisan s were fighting nearby Stara Gradiška , the Ustaše began clearing the camp , killing some of the inmates and transporting others to Lepoglava and from there to Jasenovac , where they were to be exterminated . Several survivors , like Šimo Klaić , who stressed in Šakić ' s trial that Lepoglava " was horrible , as if all the evil from Stara Gradiška and Jasenovac had concentrated there " , fled from the train cart in which they were to be transported to Jasenovac . Klaić later learned , as he testified in the court , that the other two carts in the transport were torched in Jasenovac . The camp was liberated in April 1945 by the Partisans .