Eighty years ago, a German Jewish family living in Amsterdam hatched a desperate plan. They packed up their belongings and hid from the Nazis in a tiny room at the back of a building. 

The Frank family lived in the tiny space for two years. Anne, one of the daughters, kept a diary. She described many terrible experiences they endured. 

Then, on 4 August 1944, police broke into the hiding place. Anne's father, Otto, was taken away. The rest of the family was sent to Auschwitz. 

Eventually, Anne and her sister Margot were sent to Bergen-Belsen camp. Their mother was left behind. It was the last time they saw her. In February 1945, the sisters caught typhus. They died shortly afterwards. It was only two months before soldiers freed the camp. 

Anne Frank's diary is one of the bestselling books in the world. Many have tried to find out how the Nazis found Anne's family. 

Now, we may have the answer. A team has been using modern forensic techniques to discover the Franks' betrayer. The most likely culprit is a man called Arnold Van den Bergh. He was a local Jewish businessman. 

Some say there should be justice. They think Van den Bergh's family should apologise for the harm he caused.

But the team disagrees. They say their research just proves what people do when they are desperate and trying to survive. 

Van den Bergh is an example. The Nazis knew he was Jewish, but he was never sent to a camp. Investigators think he made a deal with the Nazis to save himself and his family. 

Anne's father Otto survived the war. he spent the rest of his life trying to find out who had betrayed them. The team thinks Otto guessed who the culprit was - but that he never said anything. Perhaps he also thought it was impossible to punish somebody just trying to survive. 

Yes: Van den Bergh sold out another family for his own selfish reasons. There can be no forgiveness for those who acted in this way. 

No: Those of us who have not lived under Nazi occupation cannot possibly know what it was like. We have to accept that people had to make decisions that affected theirs and other people's lives.

Or... The Nazis used Jewish collaborators because they wanted to make the community responsible for its own oppression. We must not play the same game. This should all be blamed on the Nazis.