The Jewish community of Krasnosielc ceased to exist in early September 1939. Following the German invasion of Poland, which started World War II, SS units of Panzer Division Kempf forced the Jews into the synagogue and massacred them there. A day later, the remainder (mostly men) were machine-gunned at the same location. The anti-Jewish massacre became widely publicized in Berlin as the first of its kind on Polish soil. The perpetrators received sentences of a few years, and their superiors were replaced. In the beginning of the German occupation, the occupiers also carried out mass searches of homes of local policemen, postal workers and court employees. In the following years, several Polish teachers from Krasnosielc were murdered in the Mauthausen concentration camp (see "Nazi crimes against the Polish nation"). In 1940, the Germans also carried out expulsions of Poles and operated a transit camp for Poles expelled from nearby villages. Expelled Poles were either enslaved as forced labour of new German colonists in the county or deported to more southern locations of occupied Poland, while their farms were afforested. German occupation ended in 1945, and the settlement was restored to Poland.