Billy Wilder was a Jewish Hollywood film maker who participated in creating propaganda films
On April 11, 1945, Buchenwald was liberated by the third army of the US. Members of the psychological warfare department, a wartime department created by the United States, were the first to go into Buchenwald; no explanation is given as to why they were the first ones to go in. The PWD was an organization set up by British-American forces and were also involved to create propaganda and tactical psychological warfare against the Germans. They brought editors over to Germany such as Richard Hanser, production managers like Norbert Gruenfeld and recorders like Morris Bishop into the camp.
Germans could barely feed themselves let alone the camp prisoners, starvation was at an all-time high leaving prisoners looking like skin and bone and means of health facilities were poor as the US moved closer to the fatherland. What the allied forces walked into was a production dream; anything was possible. Billy Wilder, his crew, and the Psychwar department filmed in which ever way they could to make the scenes as horrific as possible. They also used items such as bars of soap claimed to be made out of human fat, shrunken heads taken from the prisoners, and lampshades made from human skin. All of this and more was pinned on none other than Ilse Koch, the overseer of the camp at the time.
The crew also went to other camps like Auschwitz, Majdanek, Belsen and more to film what they could manipulate. Keep in mind that the camps in the east and in Germany were being renovated on by the soviets right after their liberation to make them look like death camps which has been admitted to between 1945 and 1947. How convenient that they became museums only after their alterations and renovations were made.