During the joint German-Soviet invasion of Poland, which started World War II, in September 1939, Rybnik was captured by Germany, and the "Einsatzgruppe I" entered the city to commit atrocities against Poles. Under German occupation the city was directly annexed into Germany. The population was ethnically categorized and either "re-Germanized" or disfranchised and partially expelled into the General Government (German-occupied central Poland). Local teachers and school principals were among Polish teachers and principals murdered in Nazi concentration camps. The Germans operated a Nazi prison in the city. The "Polenlager No. 97", a forced labour camp for Poles, was operated in the city from 1942 to 1945. In the camp, the Germans mainly held children whose parents were either arrested or deported to Germany, and also elderly people. Nevertheless, the Polish resistance movement was active in Rybnik. In the final stages of the war, in January 1945, the Germans murdered 385 prisoners of the Auschwitz concentration camp in the city during a death march.