Mieczysław Kosmowski
Polish Nazi collaborator
About Mieczysław Kosmowski
Born 1913. Mieczysław Kosmowski is a Polish collaborator with Nazi Germany and collaboration in German-occupied Poland.
Mieczysław Kosmowski (born 1913; disappeared 1944) was a Polish Nazi collaborator, Gestapo agent and war criminal.
Career and disappearance Kosmowski served in the army in 1933 before working at a family farm. He was later employed at a post office in Szczuczyn. In 1940, during World War II, he committed financial fraud and fled to the German occupation zone. The Gestapo recruited Kosmowski on 30 October 1940 to cooperate with German intelligence and he was given the undercover name of Walter Krause. Kosmowski became a post office employee, and is believed to have been assigned the function of the chief of the Blue Police, (but since he was one of three brothers, it is not certain whether he was the one who became the police chief) and served as the agent of the German Security Police. One of his tasks was to incite hatred towards Jews among the local population. On 27 and 28 June 1941, a group of Poles assembled by Peniuk and the Kosmowski brothers assaulted Jews at four locations in the town. Around 300–400 people were brutally murdered.
The Białystok prosecutor's office is in possession of the original document of recruitment carried out by the Gestapo in Olsztyn. Until the German-Soviet war, Kosmowski crossed the border several times. He was last seen in 1944 in Bydgoszcz, when he evacuated with the German army. He withdrew from the German army as he was preparing to evacuate to Germany together with his masters from the Gestapo. In 1955, he was accused of denouncing several Poles to the Germans and a wanted poster was issued for him in 1957, and at the request of the court after a warrant was issued, which was valid from 1957 until 2009.
Investigation and aftermath In 2009, the prosecutors of the Białystok division of the Polish Institute of National Remembrance said Kosmowski was possibly involved in instigating the Wąsocz pogrom, Jedwabne pogrom, Szczuczyn pogrom and Łomża pogrom. According to the IPN, he operated under the codename "Gienek". The government ceased its search in 2009.
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Important facts
People in Mieczysław Kosmowski's life
Named in this biography and alive at the same time
Contemporaries
People whose lives overlapped Mieczysław Kosmowski's
Frequently asked questions
Who is Mieczysław Kosmowski?
Polish Nazi collaborator
When was Mieczysław Kosmowski born?
Mieczysław Kosmowski was born in 1913 in Świdry-Awissa.
What is Mieczysław Kosmowski's occupation?
Mieczysław Kosmowski is a collaborator with Nazi Germany and collaboration in German-occupied Poland.
What nationality is Mieczysław Kosmowski?
Mieczysław Kosmowski is Polish.
Sources & further reading
· Wikipedia: Mieczysław Kosmowski
· DBpedia: Mieczysław Kosmowski
Cite this page
APA: Biography.guide. (2026). Mieczysław Kosmowski. https://biography.guide/mieczyslaw-kosmowski/
MLA: "Mieczysław Kosmowski." Biography.guide, https://biography.guide/mieczyslaw-kosmowski/.
Chicago: "Mieczysław Kosmowski." Biography.guide. https://biography.guide/mieczyslaw-kosmowski/.
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