They believe he did it in order to protect his own family from persecution and was understood not to have known the identity of the families hiding at the addresses he gave to the Nazi police, or whether they were still there.
In the documentary, Pankoke told CBS 60 Minutes: “When van den Bergh lost all his series of protections, exempting him from having to go to the camps, he had to provide something valuable to the Nazis that he’s had contact with to let him, and his wife at that time, stay safe.”
A key piece of evidence in identifying him was an anonymous note given to Frank’s father, Otto, that informed him of the betrayal.
From 1942 until August 1944, child diarist Frank and her family hid from the Nazis in a building next to the canal in Amsterdam. When they were discovered, they were taken to Auschwitz.
Frank was killed at Bergen-Belsen concentration camp in 1945, aged 15 years old.