Of course I know Bertram was jewish. That's why they caugth him. And what I was thinking about is that the nazis in each country they "collected" jewish people they had to report to Berlin exactly how many and the names and ages of each and everone. At first how many there were in a specific town and then how many and who they caugth, who and how many they delivered for work or for extinsion to different camps.
When the prisoners arrived many were already dead during the suffering from the transportations. Count off! And then this old people and children directly to the gas chambers. Week or ill the same way. But Bertram was 22 year old and a young man.
The nazis must have rekognized him as a usefull worker. Every morning and evening the nazis were counting and wrote down deaths. They, the nazis were awfully good at making statistical reports.
They did destroy a lot of these reports in 1945 but be sure it was to many to destroy them all. I have seen Auswitch in Poland in 1973. I was young and refused to leave the bus. It was horrifying to only see the organized hell. In 2007 I was in Berlin and we then went one day to Sachsenhausen "Gedänkstedt". Most of the prisoners there had been documented from the arrival til death. There is a big library and archive. The nazis documented all details so to be able to construct the history of their Third reich. And they did not give up early enough to destroy all the proofs.
So if they caugth Bertram they must have known about his existance in NL 1941. His transport must be documented as his arrival. The nazis went to all census in all countries they occupied. They knew all existing jews by name and caugth them one by one in kind of a count down until they hade emptied a city or village. All the tatued numbers were registered connected to a person. If a member of a family slipped out of their net, they knew who was "missing" and they went on searching.
Of course many died from starvation and illnes too but one can be quite sure that this was noted as progress concerning the overall nazi goal to kill all jewish people in the world.
I do wish your film will reach many people in the world. It's important to make Bertam to a living person to other young people today and in the future. It's very important.