During Operation Tannenberg patients from Polish hospitals were murdered in Wartheland (Wielkopolska) by Einsatzgruppe VI under Herbert Lange.
He was appointed commandant of the first Chełmno extermination camp soon thereafter.
By mid-1940, Lange and his men were responsible for the murder of about 1,100 patients in Owińska, 2,750 patients at Kościan, 1,558 patients and 300 Poles at Działdowo who were shot in the back of the neck; and hundreds of Poles at Fort VII where the mobile gas-chamber (Einsatzwagen) was first developed along with the first gassing bunker.

According to the historian Peter Longerich, the hospital massacres were conducted on the initiative of Einsatzgruppen, because they were not ordered by Himmler.
Lange's experience in the mass killing of Poles during Operation Tannenberg was the reason why Ernst Damzog, the Commander of Sicherheitspolizei (Security Police) and SD stationed in occupied Poznań (Posen) placed him in charge of the SS-Sonderkommando Lange (special detachment) for the purpose of mass gassing operations which led to the eventual annihilation of the Łódź Ghetto.
During Operation Tannenberg patients from Polish hospitals were murdered in Wartheland (Wielkopolska) by Einsatzgruppe VI under Herbert Lange. He was appointed commandant of the first Chełmno extermination camp soon thereafter. By mid-1940, Lange and his men were responsible for the murder of about 1,100 patients in Owińska, 2,750 patients at Kościan, 1,558 patients and 300 Poles at Działdowo who were shot in the back of the neck; and hundreds of Poles at Fort VII where the mobile gas-chamber (Einsatzwagen) was first developed along with the first gassing bunker.
According to the historian Peter Longerich, the hospital massacres were conducted on the initiative of Einsatzgruppen, because they were not ordered by Himmler. Lange's experience in the mass killing of Poles during Operation Tannenberg was the reason why Ernst Damzog, the Commander of Sicherheitspolizei (Security Police) and SD stationed in occupied Poznań (Posen) placed him in charge of the SS-Sonderkommando Lange (special detachment) for the purpose of mass gassing operations which led to the eventual annihilation of the Łódź Ghetto.
Operation Tannenberg