Of the tragedies that played out at the three Action Reinhard camps, Belzec is the most mute. There are only two known survivors of Belzec to describe what they saw and experienced. One of the men, R. Reder, wrote a book published in Crakow in 1946. the second, named Chaim Herszman, was a witness before a Polish commission set up to investigate German war crimes. Herszmen had escaped from a train transporting him and last Jewish workers to Sobibor for execution Thet were being carried from from Belzec after the demolition of that camp. Hirszman lived to see the end of Nazism and had completed part of his deposition beore the Polish commission when it adjourned. He was to return the next day to complete his testimony. He never made it; he was murdered by Polish anti-Semites. Other first hand testimony exists from Polish and German Sources. The former were very restricted in the time and place they had to observe. The latter suffer from the obvious interest they had had in limiting their culpability.
Much of the first hand material available - verbal testaments by victims and perpetrators are conflicting, terse, and suffer from memory lapses due either to the passage of time or the need for self protection. Some just due to the number of years that had passed after the events they witnessed. There are great gaps in the narratives, and there is no possibility of amplification because in the passage of time, memories fade, or the witnesses die. The most reliable sources, photographs, are few and scattered. At Belzec, there were a number of Luftwaffe reconnaissance missions flown over the camp. All but one were flown after it was liquidated and all clustered in the period of May through September 1944. The single exception is photography flown in 1940 before the camp was built. Each member of the SS at the camps signed a secrecy oath which explicitly prohibited photographs. This stricture was violated at Treblinka by The Deputy Commandant, Kurt Franz. Franz took perhaps three dozen snapshots, most of which were only peripheral to the real functions of the camp. Nevertheless, at Treblinka, the pictures Franz took served to substantiate much of the testimonies about the death camp. At Belzec hand held camera pictures are even scarcer, and none were taken in the death camp area as happened at Treblinkla. Those few are not particularly compromising. Thus, the reconstruction required a dependence on the aerial photos, which, while objective sources, require experience and knowledge for proper interpretation, and the judicious use of the collateral testaments.
Alex Bay has used these tools for a reconstruction of Belzec.