The Germans attacked Krotoszyn on 1 September 1939, the first day of the invasion of Poland and World War II. On 2 September they bombed a train with Polish civilians fleeing the Wehrmacht from Krotoszyn, killing 300 people and on 3 September they captured the town. The Germans established a transit camp for Polish prisoners of war and over 4,500 Polish soldiers passed through the camp. In mid-September 1939, the "Einsatzgruppe VI" entered the town to commit various crimes against the Polish population.