Nazi German authorities limited the education of ethnic Polish children to only four years during the occupation of Poland in order to undermine Polish culture. Despite the ban, Dobrowolski joined the Secret Teaching Organization to provide underground education in occupied Poland, according to Auschwitz historian Adam Cyra. Dobrowolski was discovered and arrested in June 1942 by the Gestapo. He was sent to the Auschwitz concentration camp, where he was assigned the prisoner number 38081. Dobrowolski later recalled that "Auschwitz was worse than Dante's hell." He was transferred to the Gross-Rosen concentration camp and Sachsenhausen concentration camp, remaining a prisoner until his release in 1945.