For two years, Anne Frank's family hid in secret rooms in Amsterdam, knowing that a curtain left open by mistake, a wayward noise or a nervous conspirator's phone call to the Nazis could land them all in concentration camps.
The worst happened on a summer day in 1944, when investigators discovered their secret world behind a movable bookcase and rounded them up.
Of the eight Jewish people seized, seven died before the Holocaust was over, including Anne, whose diary was a testament to the horrors of the Nazi regime. She died of typhus at age 15 at Bergen-Belsen camp in Germany.
For decades, Anne's father, Otto, tried to figure out who tipped off the Nazis — a question historians have debated for 72 years.
Now, the Anne Frank House museum in Amsterdam has put forth a new theory: It was a coincidence.
For decades, the common theory has been that Anne Frank's family was betrayed, possibly by a new employee at her father's business or a conspirator's wife, unsympathetic to the plight of the eight Jews.
But according to a research paper published this month by the Anne Frank House, “this explicit focus on betrayal, however, limits the perspective of the arrest. … [O]ther scenarios tend to be overshadowed.”
Previous theories were based on Otto Frank's suspicions, which centered on Willem van Maaren, a new employee who hadn't been let in on the secret about the hiding place.
“We suspected him all along,” Frank told a Dutch newspaper in 1963.
On its website, the museum says van Maaren was an inquisitive type who became suspicious and “laid a trap in the warehouse once: on the corners of the tables there are sheets of paper which fall off when you walk past.”
Still, no conclusive evidence has ever come to light of van Maaren alerting authorities, the paper says.
Through the decades, others have been identified as potential betrayers, including Dutch National Socialist Tonny Ahlers, as well as the wife of an employee who helped Anne's family hide.
But no one has cast serious doubts about the betrayal theory — until now.
In part, that is because historians believed the three investigators who found the Jews hiding in the Opekta building were members of the Sicherheitsdienst, which tracked down potential enemies of Hitler's Nazi regime.
— Anne Frank Trust (@AnneFrankTrust) July 27, 2016
But new information uncovered by researchers showed the three men Otto Frank later identified as the investigators weren't looking for enemies of Nazis, but were likely assigned to track down people committing ration card fraud or dodging service in the military — not hunting down Jews.
Gezinus Gringhuis, for example, had previously been assigned to track down Jews, but had a new assignment — “investigating economic violations,” according to the research paper.
In her diary, Anne repeatedly wrote about the arrests of men who had been caught dealing in illegal ration cards “so we have no coupons.”
Such arrests were often reported to authorities, who frequently came across hiding Jews as they tried to sniff out people with phony ration cards.
The research paper also highlights other circumstantial evidence that pokes holes in the betrayal theory. Many phone lines were cut off, for example, which would make it hard for civilians to call authorities about Jews in hiding.
“This creates a real possibility that the call, if it actually took place, came from another government agency,” the paper says.
The paper stressed that there is no conclusive theory about how Anne's family was discovered — including its own hypothesis.
“In any case, the Anne Frank House's investigative report indicates that more was going on in the building (than) only people being hidden there,” it says. “The possibility of betrayal has of course not been entirely ruled out by this. … Clearly, the last word about that fateful summer day in 1944 has not yet been said.”
The interest in the betrayal of a teenage girl seven decades after her death is a testament to the universality of Anne's powerful tale.
Many have pointed out the historical similarities between the plight of Anne's family and the current debate about Syrians seeking refuge in the United States. As The Washington Post's Elahe Izadi wrote, the Franks collided with restrictive policies "designed to protect national security and guard against an influx of foreigners during [a] time of war.”
The Franks were unable to immigrate to the United States and instead lived in a hidden storeroom.
And a 7-year-old Syrian girl, Bana al-Abed, has been called a modern-day Anne Frank, according to The Post's Caitlin Gibson. Bana amassed 200,000 Twitter followers while documenting her family's struggle to survive in war-ravaged Aleppo.