In September 1939, in the beginning of World War II, the city was invaded by Germany, and shortly afterwards the German "Einsatzgruppe I" operated in the city and committed various crimes against the Polish population. Also in September 1939, Wehrmacht troops carried out a massacre of 14 Polish boy scouts from nearby villages in the present-day district of Tucznawa. Poles from Dąbrowa Górnicza were among the victims of massacres committed by the Germans in other places, including Sosnowiec on September 4, 1939 and Celiny on June 4, 1940. Under German occupation the city was annexed directly to Germany, and included within the Upper Silesia Province. At least 14 Polish policemen from Dąbrowa were murdered by the Russians in the large Katyn massacre in April–May 1940. Further executions of Poles were carried out by the Germans during the war. Over 40 local Polish boy and girl scouts were killed by the Germans in various places, including the Auschwitz concentration camp and during the Warsaw Uprising of 1944, and over 60 local miners were also murdered in Auschwitz. In October 1941, the occupiers expelled over 100 Poles, who were then sent to forced labour either to Germany or to various factories in the region, while their houses were handed over to German colonists as part of the "Lebensraum" policy. German occupation ended in 1945.