There have been many theories and investigations over the years.
Over the years there have been many accusations about who could have betrayed the Frank family hiding out at Prinsengracht 263 in Amsterdam during World War II. Anne Frank’s diary, which she kept from 1942-44, eloquently told the story of the family and the 4 others who lived in the secret annex apartment during these years. On August 4th, 1944, the secret annex was raided by officers of the Sicherheitsdienst (or SD), an intelligence division of the Nazi regime, and the 8 people in hiding were sent to different concentration camps. To this day, there are a number of theories about how the Nazis knew to look for the family in the well-hidden area of the building. It begs the question: who betrayed Anne Frank’s family?
In 1942 the Frank family, concerned with the ever growing violence towards Jews in Nazi-occupied Netherlands, went into hiding at a canal street building with a commercial space on the first floor. The family patriarch, Otto Frank, had moved the family from Germany to Amsterdam in 1933 when he was offered a position running the Opekta spice and pectin company. Mr. Frank had been worried about the rise of the Nazi party even then and had thought he was moving his family to safer ground. Little did he known that soon the Netherlands would become a Nazi-occupied country.
Mr. Frank remained a silent partner in the business even after the Nazi regime took control, and the family was completely dependent on the 6 employees who were helping them to stay hidden. The helpers brought food and supplies and made sure to the best of their ability that nothing happened to the Frank family. But, after the war Mr. Frank (who survived being a prisoner at Auschwitz) began an investigation to find out who turned them into the SD.
In the fall of 1945 Mr. Frank began his own research into who could have tipped off the Nazi authorities. He had the suspicion that the informant could have been Willem van Maaren, an employee of the Opekta company and someone who the helpers and the Frank family began to distrust during their time in hiding. However, a 1947 police inquiry did not find enough evidence to charge van Marren.
Another person who is often said to have alerted the SD to the Frank family is Ans van Dijk, a Jewish woman who became an informant for the SD after being arrested herself. Using the intelligence van Dijk provided 145 Jews are known to have perished, though it is possible that many more were arrested thanks to her information. Many books have offered van Dijk as the informant, but research into her life completed by the Anne Frank House Museum was unable to prove that she was the one who betrayed the Franks.
Another famous theory on the matter is that an unnamed informant made a phone call to the SD. During the period in which the Franks were discovered, the phone lines around Amsterdam were not all in operation, which means that most civilians would have not been able to make any phone calls. Follow up interviews with SD police chief, Willy Lages, in 1963 showed that if they had received an anonymous tip the morning of the arrests they would have most likely examined the credibility of the informant before acting on the lead. This protocol might have been abandoned if the informant was previously known to the SD as a reliable source.
It remains possible that the police were tipped off by someone, but the Anne Frank House Museum has concluded, after years of looking into the matter, that there was another strong possibility. According to the museum, some employees of Opekta were engaged in crooked bookkeeping and ration coupon fraud which may have initially brought the SD to their door. The discovery of the Frank family, the Van Pel family, and Fritz Pfeffer- all of whom were hiding together at Prinsengracht 263- could have been incidental to the attempt to catch the fraudsters working for Opekta.
No police documents of what led to the arrest exist today, so it is impossible to gain more clues from official paperwork. But, we have contend with the possibility that the building could have been raided for reasons completely unrelated to the 8 people hiding upstairs.
Following the raid Otto Frank was sent to Auschwitz, which he survived. He died in 1980 and was the only one of the secret annex to survive the war. Anne, and her older sister, Margot, were separated from Otto at Auschwitz and then later sent to Bergen-Belsen concentration camp where they perished in early 1945. Their mother, Edith, died of starvation at Auschwitz in January 1945 after having saved all her food for her daughters who were no longer at the camp.