Hejnoch Bren(n)er was deported to the Treblinka Camp on 15 October 1942. He was interrogated by a Soviet investigative commission on 17 August 1944. Regarding the way people were allegedly killed at Treblinka, he stated merely that 5,000 people were killed at a time in the “bath.”
During another interrogation by Polish judge Zdzisław Łukaszkiewicz on 9 October 1945, he claimed that Jews at Treblinka “were killed by pumping the air out with a motor located next to the chambers.” However, creating a vacuum in a brick-and-mortar building is technically impossible (the external pressure would crush the walls), hence most certainly was not done.
Brener furthermore claimed to have been a barber cutting women’s hair. He claimed that this was done in one of the alleged vacuum chambers, so he knew exactly how they looked and operated. However, the orthodoxy insists that haircutting occurred in a separate building, not inside one of the gas chambers.
(See Mattogno 2021e, pp. 138, 155f.)