The first Aktion, conducted by Wehrmacht soldiers and gendarmes, took place in December 1939, in which 100 Jews were executed. In June 1940 the Germans expelled 514 Poles, merchants and craftsmen with entire families, mostly to the General Government, while some were deported to forced labour to Germany, and their houses, workshops and shops were handed over to German colonists in accordance to the Nazi "Lebensraum" policy. In December 1940, the Jews were rounded up in a ghetto, which was liquidated the following year, in December 1941. The remaining Jews were deported to Chełmno extermination camp, where they were killed in gas vans and buried in mass graves. Koło remained a transfer point for Jews deported to Łódź, and Nazi officials, including Heinrich Himmler, visited the town.