In October 1939 an early experiment in execution by gas chamber was carried out by an SS chemist, Dr. August Becker,[2][p. 175] whereby around 400 patients and staff from psychiatric hospitals in Poznań were gassed at Bunker No.

[1] The extermination of mentally ill was conducted by SS-Sturmbannführer Herbert Lange of the Gestapo in occupied Poznań.

According to conservative estimates of the Fort VII State Museum, a total of 18,000 prisoners passed through the camp, of whom 4,500 died.

Deaths were the result of either to execution: including shooting, hanging or gassing; mistreatment, torture, and contagious disease.

[1] On the 20 October 1939 the first Jewish victims from Posen (Poznań), Benno Rindfleisch and Julius Tychauer, were shot at Fort VII.

But the majority of the Jewish population of Posen was transported to the Lublin district, most likely ultimately perishing at Belzec or Sobibor.

Prisoners included citizens of other countries as well as Polish nationals, from the Soviet Union, Yugoslavia, France, the United Kingdom, as well as some Germans.

On the "stairway of death" prisoners would be made to run up carrying a heavy stone, and possibly kicked down from the top by a guard.

Only one prisoner is known to have escaped – Marian Szlegel, thanks to his work, was able to identify a time when the camp was less well guarded, and took the opportunity to abscond.

Prisoners were made to work on the construction of a new camp south of Poznań, in Żabikowo (called Poggenburg by the Germans), and were then transferred there, the last ones being moved on 25 April 1944.

Fort VII became a Telefunken factory producing radio equipment for submarines and aircraft.