Updated

Historians have long believed that Anne Frank’s arrest was the result of a betrayal, but experts in Holland are now proposing an alternate theory about her capture by the Nazis.

Anne Frank and seven other Jews hid in the secret annex on Prinsengracht street in Amsterdam beginning in 1942, until the Nazis discovered and arrested them on August 4, 1944. That devastating discovery eventually led to the death of everyone save for Otto Frank, with Anne and her sister perishing in Bergen-Belsen concentration camp in 1945.

But while the conventional wisdom has always been that the group in hiding were betrayed, the Anne Frank House is challenging that assumption in a new investigative report. They’ve proposed: What if the group was simply discovered by accident?

“Despite decades of research, betrayal as a point of departure has delivered nothing conclusive,” Ronald Leopold, the executive director of the Anne Frank House, said in a statement. “The Anne Frank House's new investigation does not refute the possibility that the people in hiding were betrayed, but illustrates that other scenarios should also be considered. Hopefully more researchers will see reason to follow up new leads.”

The Anne Frank House’s new investigative report (summarized in a brief document) focuses on a few details that suggest that the group could have been discovered by accident, perhaps because authorities were investigating whether there were other activities— like food ration card fraud or people working illegally— happening at the building where the secret annex was located.

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One angle of the investigation focuses on the authorities who actually conducted the raid. The report argues that three of the men in the raid may not have been first and foremost looking for Jews in hiding, and could have been investigating something else; specifically, one man, Gezinus Gringhuis, no longer worked for the Sicherheitsdienst (German Security Service), and instead was with an organization called the Special Unit of the Central Investigation Division, “where his responsibilities did not include hunting down Jews, but investigating economic violations,” the document says.

Another angle focuses on a telephone call to the Sicherheitsdienst that supposedly took place before the arrest, tipping off the authorities. The report points out that the phone numbers for that service were not publicly listed at that time. “This creates a real possibility that the call, if it actually took place, came from another government agency,” the document says.

Still another clue came from Anne’s diary itself, in which she mentioned more than once the fact that two people were arrested because of their involvement with illegal food ration cards.

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Ultimately, the new report doesn’t exclude the possibility that the group was betrayed, but it does call on people to explore “new leads.”

“Clearly, the last word about that fateful summer day in 1944 has not yet been said,” the document concludes.

Follow Rob Verger on Twitter: @robverger