Eighty years ago, a German Jewish family living in Amsterdam hatched a desperate plan. Edith, Otto, Margot and Anne Frank packed up their belongings and hid in an annexe at the back of Otto's workplace.

The family would live in this tiny space, just 42 square metres, for the next two years. During this time, Anne kept a diary that would later become famous for its stories of the Nazi occupation. 

Then, on 4 August 1944, German police stormed their hiding place. At first the Franks were sent to Auschwitz, then Anne and Margot were relocated to the Bergen-Belsen camp, where they died in February 1945. Just two months later, British forces liberated Bergen-Belsen.

Since then, Anne Frank's diary has become one of the bestselling books in the world. And many have dedicated themselves to the question of how the Nazis found her family.

Now we may finally know the answer. A team led by former FBI investigator Vince Pankoke has used modern forensic techniques to trace the Franks' betrayer. They think the most likely culprit was a Jewish notary named Arnold van den Bergh. 

Some argue van den Bergh's family should apologise for the harm he did to his neighbours. But the team says that the purpose of their work is not to find someone to blame. It is to show how desperation makes people do terrible things.

Van den Bergh was Jewish and the Nazis knew it. Yet neither he nor his family were ever sent away to the camps. The investigators think he might have made a deal with the Nazis, handing over hidden Jews for his own family's freedom. They suggest he was doing what was needed to protect those he loved.

They argue almost anyone might have betrayed the Franks if it could have saved their own lives. People did what they had to just to get by under the Nazi regime. We cannot blame ordinary people for trying to survive.

Yes: No matter what his motives, van den Bergh sold out another family to keep his own safe. There can be no forgiveness for those who participated in the Holocaust in any way.

No: Those of us who have not lived under Nazi occupation cannot possibly know what drove van den Bergh to do what he did. We have to accept that people make moral compromises under that kind of pressure.

Or... The Nazis used Jewish collaborators because they wanted to make the community responsible for its own oppression. We cannot play their game: all blame must be placed squarely on the Nazis.