It’s been more than 72 years since Anne Frank and her family were arrested in their hiding place in Amsterdam—an arrest historians have long thought was instigated by an infamous betrayal. But that may not be how the story really unfolded. As Cleve R. Wootson, Jr. reports for The Washington Post, new evidence suggests that Frank’s family was not betrayed after all.

Historians are still studying the events of August 4, 1944, when Anne and the seven other Jews she hid with in increasingly tense circumstances for over two years were arrested and taken ultimately to concentration camps. As Wootson reports, previously overlooked clues in Anne’s own diary helped trigger a new theory on what really happened that day.

In a newly published report on the arrest, historian Gertjan Broek of the Anne Frank House reveals why previous theories that the eight Jews hidden in an Amsterdam annex behind a movable bookcase were betrayed are likely wrong. The old story went like this: Someone found out that a group of Jews were hiding in an office building in the heart of Amsterdam, then ratted them out to Nazi authorities. (That view was shared by Otto Frank, Anne’s father and the only one of the eight people who hid at 263 Prinsengracht to survive the Holocaust.)

The identity of the betrayer has long been a source of heated debate. First, fingers were pointed at Willem van Maaren, who worked in a warehouse below where the Jews were hidden by coworkers of Otto Frank, Anne’s father. Despite two investigations into his involvement in a potential betrayal, he was never conclusively proven as the betrayer. Biographer Melissa Müller later pointed the finger at Lena-Hartog van Bladeren, who regularly cleaned the building, and a Dutch man named Anton Ahlers claimed in 2002 that his anti-Semitic father betrayed the Franks and then may have gone on to blackmail Otto after the war. But neither case was ever proven.

Now, Broek contests that the Franks weren’t betrayed at all. Rather than look for who betrayed them, he contests, historians should look at why the August 4, 1944, raid took place. That perspective led Broek to look more closely at the circumstances surrounding the Franks’ arrest. It took at least two hours for authorities to search the house, apprehend the eight people in the annex and move on—which, Broek suggests, implies that the building was being investigated for more than hiding Jews.

Broek learned that the investigators who arrested the Franks that day were not assigned to hunting down Jews, but rather were on duty to spot “economic violations.” Anne herself verifies that such violations were afoot in her diary, where she writes about the family’s difficulties after the men who provided helpers with illegal ration cards were arrested. And since phone lines were unavailable to anyone outside of the government at the time, writes Broek, it’s unlikely that the family was betrayed by a concerned civilian. Rather, he concludes, the family was likely inadvertently discovered during an investigation concerning ration card fraud.

We will never know for sure what transpired during the arrest—as Broek himself admits. However, he suggests that it makes more sense for historians to “[think] more broadly” about the event’s context than to focus exclusively on whether the family was betrayed.

Still, given the enormous amount of scholarship and interest in the teenage diarist and her fellow persons in hiding’s tragic fates, seven decades of work should have helped reconstruct the tragic events surrounding their years in hiding, arrest and eventual death.

But that’s not the case: Just last year, for example, historians uncovered evidence that suggests that Anne Frank died a month earlier than previously thought. Perhaps with the help of new perspectives like Broek’s, historians will uncover even more about Anne’s life and death. Given Anne’s continued relevance as a figure of resistance and courage in the face of unthinkable persecution, it’s worth a try—even if what exactly happened on that August day can never be completely reconstructed.

Editor's note, 1/2/2017: This story has been edited to reflect that after everyone in the Secret Annex was arrested, they were sent first to the Westerbork transit camp, and then on to Auschwitz.