Transcript of narration in film shown at Nuremberg Trial in which Dachau gas chamber is described 

Document PS-2430: Nazi Concentration and Prisoner-of-War Camps: A Documentary Motion Picture, film shown at the Nuremberg Trial, 29 November 1945, IMT, XXX, p. 470:

"Dachau- factory of horrors. [ ... ] Hanging in orderly rows were the clothes of prisoners who had been suffocated in the lethal gas chamber. They had been persuaded to remove their clothing under the pretext of taking a shower for which towels and soap were provided. This is the Brausebad -- the showerbath. Inside the showerbath -- the gas vents. On the ceiling -- the dummy shower heads. In the engineers room -- the intake and outlet pipes. Push buttons to control inflow and outtake of gas. A hand-valve to regulate pressure. Cyanide powder was used to generate the lethal smoke. From the gas chamber, the bodies were removed to the crematory."

The film that was shown at the Nuremberg IMT can be seen on the web site of the United States Holocaust Memorial Musuem. A 22-minute movie shown in the Museum at the Dachau Memorial Site contains some footage from this film.