Anne Frank told her story through her diary of her life during WWII as a young Jewish girl. It opened a lot of people's eyes and helped people understand what it was like for the Jews at this time. Her diary is available worldwide and is used as a way to help teach how WWII was for the Jews at the time.
By August 4, 1944 police in Nazi-occupied Amsterdam raided a warehouse. Anne Frank and 7 other Jews who were hiding in an annex behind a bookcase were found and arrested along with their 2 helpers.
It was believed by those involved that someone had betrayed the group. That some one called the SD and let them know where they were hiding. There was no evidence that this had happened.
Anne's father Otto and believed it to be, a worker at the warehouse, who wasn't in on the deal. He claimed he wasn't the one to betray the group.
SD officer Silberbauer who was involved with the arrest only mentioned "a Dutchman" as the caller. But his statements were inconsistent as he later stated he didn't know if a phone call was even made. He was asked about this around 20 years after the fact. so his memory may have been hazy for this specific arrest or merged with a memory of another. The human memory is a fickle thing.
In another story, is Julius Dettmann an SD officer stated that it was a woman who made the call. Dettmann died two weeks after liberation in his cell. Silberbauer stated Dettmann never told him who had made a call or if it was a woman. Someone had told Otto Anne's father that Dettmann told them it was a woman.
The people betrayed that day believed that it may have been William Van Maaren. He was a worker at the warehouse and wasn't in on the deal. The people in hiding shared their suspicion of him even though they never got to meet him. Otto later filed a complaint with the political police, but it was dismissed as there was no evidence he had done it and he claimed to not have had anything to do with it.
Tony Ahlers is another suspect in the betrayal. He is a Dutch national socialist and Otto did not get along. He knew Otto was against the German war chanced and pressured and extracted money from him. There was no evidence though that he had known they were hiding in the Annex.
A female suspect of the betrayal was Lena Hartog. Her husband Lamont worked for the warehouse and had told her that he had helped hide people in there. She knew there were people hiding there, but it isn't known if she was told before or after the fact of the raid.
Another female suspect was Ans van Dijk who was a Jewish woman forced to help the SD turn in other Jews.
There is still no idea of who turned in them and it is still being investigated today.
SOURCES:
History