Researchers the the Anne Frank Museum in Amsterdam have spent years searching for the answer to who betrayed Anne Frank and her family.

Now, a new study suggests the world-famous diarist may have been found by chance after police began investigating a ration fraud.

The raid on Prinsengracht 263 saw all those in hiding captured and sent to Nazi death camps.

Summarizing the findings, the Anne Frank House said: "The question has always been, who betrayed Anne Frank and the others in hiding? "This explicit focus on betrayal, however, limits the perspective on the arrest."

The release notes that "it is possible that the SD [German Security Service] searched the building because of this illegal work and fraud with ration coupons, and that the SD investigators discovered Anne Frank and the seven others in hiding simply by chance."

Researchers are now questioning whether this call was actually made. Looking at a diary entry from March 10, 1944, Anne writes about having "no coupons" due to the arrest of two men.

The man are named as "B" and "D", which stood for Martin Brouwer and Pieter Daatzelaar. Both men worked as salesmen for a firm based in Prinsengracht 263, where Anne's father also had a business.

Looking at the police who discovered the Frank family, researchers also found they were not men usually tasked with searching for Jews in hiding, but usually worked on cases involving cash and security.

The young writer died of typhus at the Bergen-Belsen concentration camp.

"During their day-to-day activities, investigators from this department often came across Jews in hiding by chance," according to the study, which notes that there is no evidence that an anonymous phone call long thought to have betrayed the family actually happened. The study notes that two men who worked in the building were arrested earlier in 1944 for dealing in illegal ration cards, and Anne wrote about the arrest in her diary, according to reports. There is also evidence that the German occupiers had been investigating people working at the address when they should have been sent for forced labor elsewhere. It is still possible that Anne, who died in the Bergen-Belsen camp in 1945, was betrayed, but the study "illustrates that other scenarios should also be considered," says Ronald Leopold, the museum's director.