During the occupation, in the nearby hollows and depressions, the Germans executed Polish prisoners. Testimonies of the local population bear witness to these events, partially confirmed through investigations by the Institute of National Remembrance (IPN). Work to uncover the full picture of the tragic events that took place in Kadzielnia is still ongoing.
The IPN has established that on January 25–26, 1940, the Germans murdered “an undetermined number of victims” at this site. Evidence is still being examined to confirm whether executions of Poles had already taken place in Kadzielnia as early as 1939. Among those believed to have perished here were residents of Nowy Dwór Mazowiecki and Zakroczym (including Mayor Tadeusz Hanzlik), and possibly also prisoners from Warsaw’s Pawiak prison. Testimony given by Alma Majert indicates that Kadzielnia was also used by the Germans for carrying out Aktion T4, which the National Socialists described as the extermination of “life unworthy of life”—people with mental and physical disabilities.
One of the formations implementing this brutal plan was the Gestapo. The extermination of the population was actively supported by some members of the local community of German descent, who had lived in the area before the war and knew very well which Poles displayed especially patriotic attitudes.