In February 1946, the wily Soviet prosecution team at the main Nuremberg trial submitted "irrefutable evidence"1 that 1,500,0002 and 1,700,0003 people were murdered by the Germans at Majdanek. But the Soviets weren't done there, they also claimed 2,000,000 people were killed at the camp, and in this post I'll provide three separate sources which confirm this higher claimed death toll for Majdanek.
Dr. Anna Ziębińska-Witek, Assistant professor of Jewish and Holocaust studies at UMCS, Lublin, recently wrote about the first exhibition  at Majdanek. She based her musings on six photographs of the exhibition found in the Majdanek museum's archives. She writes:6
"What attracts attention in the exhibition photographs are first of all dummies with terribly emaciated faces. These figures, wearing concentration camp stripes or worn-out civilian clothes, were stood on empty Zyklon B cans. One of the photographs also shows a dummy of a child: a girl with pigtails, terribly lean, wearing a dress and oversized shoes. [...] probably to intensify the horror, a human skull was placed on one of the shelves (made by putting a wooden board on the Zyklon B cans)."
2,000,000 Deaths, Source 2
Costello stated in his report:
3. USSR-93, Official report of the Polish Government, IMT Vol. 7, p. 214, 9 Feb 46. The report's figure is based on the stated death toll of 1,700,111 which appeared in the December 2, 1944 judgment of the Lublin trial of the 4 SS men and 2 kapos discussed in "2,000,000 Deaths, Source 2", cf. Jürgen Graf, Carlo Mattogno, Concentration Camp Majdanek: A Historical & Technical Study (Third Revised & Expanded Edition), Washington DC: The Barnes Review, 2012, p. 80.
4. Translation from: "The Representation of Death in Exhibitions: The Case of the State Museum at Majdanek" by Dr. Ziębińska-Witek, in Simone Gigliotti et al. (eds.) Ethics, Art, and Representations of the Holocaust: Essays in Honor of Berel Lang, Lanham (MD): Lexington Books, 2013, p. 279.
5. When I visited Majdanek in early November 2012, the whole of Barrack 62 was cordoned off because of building work was being carried out on the structure. On my next visit to Majdanek, in late September 2013, there was a new exhibition in Barrack 62 titled "The Displaced from the Zamość Region in the Majdanek Camp," and the sign in the picture above was no longer present.
6. "The Representation of Death in Exhibitions," opt cit. (note 4), p. 268.
7. UK NA: FO 371/50975, U3430; report also found in FO 688/32/7; and quoted in full in: James McNeish, The Sixth Man: The Extraordinary Life of Paddy Costello, London: Quartet Books, 2008, p.313-318.