During the Second World War, Konin was part of the land annexed by Nazi Germany ("Reichsgau Wartheland"). During the German occupation, mass murders of Poles were committed by the Germans at the local Jewish cemetery in November 1939 and in the spring of 1940, in which 94 people were killed, some as part of the German "Intelligenzaktion" and some as punishment for their involvement in the defense of Poland during the German invasion of Poland of September 1939. Poles were also subjected to expulsions to the so-called General Government, carried out in late 1939 and in 1940, which especially pertained to owners of more well-kept houses, shops and workshops, which were then handed over to German colonists as part of the "Lebensraum" policy. In the town's surrounding forests, the Nazis carried out mass executions of Jews, 95% of which were killed or sent to concentration camps. In August 1943, the Jews at the labour camp at Konin, led by Rabbi Joshua Moshe Aaronson, burned down the huts in the camp and tried to escape. Almost all of them were killed.