World War II diarist Anne Frank might not have been betrayed to the Nazis as was previously thought, the Anne Frank House museum in Amsterdam said on Friday. A new theory by researchers working on the teenager’s life during the Holocaust says the police might have chanced upon Frank and the seven other Jews living at Prinsengracht 263 during a ration fraud raid. All eight of the hidden Jewish residents were subsequently sent to the Auschwit concentration camp.

The Anne Frank House, in a post on its website, wrote, “The question asked has always been ‘Who betrayed Anne Frank and the people in hiding’? This explicit focus on betrayal, however, has limited the perspective on the arrest.” Researchers from the museum said they used the diary as a primary source, and tracked down police and judicial documents to find out why the raid at the Secret Annexe took place.

The study theorises that several kinds of illegal work and ration fraud were being carried out at the house, which might have led the police there. Previously, it was believed that members of the Germany secret society Sicherheitsdienst had come looking for Jews in hiding, a theory the researchers said was ridden with inconsistencies.

German-born Frank became one of the most widely known victims of the Holocaust after her diary, chronicling her life in hiding between 1942 and 1944, was published. The Franks lived in Amsterdam under the Nazi regime, and hid during that period in a set of rooms concealed behind a bookcase in an office building. Frank and her sister are believed to have died of typhus after they were transferred from Auschwitz to the Bergen-Bergen concentration camp. Her father Otto survived, and worked on getting her diary, written originally in Dutch, published.