After 77 years, a team of investigators believes they have identified the person who betrayed Anne Frank's location to the Nazis, ultimately leading to the death of her and most of her family.

In 1942, the Frank family moved into a secret apartment hidden inside her father's business in the German-occupied Netherlands. For two years they lived here, where Anne wrote her famous diaries, which would be published after her death. On the morning of August 4, 1944, Nazi police showed up at the business and found the family hidden in the secret annex. They were taken to the concentration camps Auschwitz, and for Anne and her sister, later, Bergen-Belsen, where they both died. Her father was the only family member to survive the camps. 

Over the years, many names have been suggested as possible informants, who revealed the family's address: from stockroom manager, Willem van Maaren, whom the Frank family did not trust, to Bep Voskuijl, who helped the family while they hid, but may have inadvertently passed the information on to her sister Nelly, who was a Nazi collaborator between the ages of 19 and 23.

Other proposals — including by the Anne Frank House museum in Amsterdam in 2016 — are that they were discovered by chance, or their location was revealed when Martin Brouwer and Pieter Daatzelaar, business partners of Anne's father Otto, were caught for dealing in rationing coupons. The two were the source of ration coupons for the family, according to analyses of Anne Frank's diary.

The current team of investigators, which includes a former FBI agent and a number of historians, think that Arnold van den Bergh, a high-profile Jewish notary working in Amsterdam, was ultimately the person who revealed the Franks' whereabouts. After six years of research, eliminating 11 other suspects, they name van den Bergh as the probable suspect based on how he was treated by the Nazis — even being categorized as non-Jewish — as well as an anonymous note sent to Otto Frank after his family's death.

The team, who will publish a book on their findings, The Betrayal of Anne Frank: A Cold Case Investigation, notes that van den Bergh was a member of the Jewish Council, which enforced Nazi policies in Jewish areas. In 1943, the council was disbanded, with most of its members sent to concentration camps. However, van den Bergh was allowed to continue living in Amsterdam.

"Van den Bergh wasn't deported," Dutch journalist Pieter van Twisk, who was part of the investigative team, told CBS News. "We went into the city archive and found proof that actually he was 'Aryanized,' so he lost his Jewish identity during the war. That was quite a feat. You couldn't just do that."

What caused him to betray the Franks?

"When van den Bergh lost all his series of protections exempting him from having to go to the camps, he had to provide something valuable to the Nazis that he's had contact with to let him and his wife at that time stay safe," former FBI agent Vince Pankoke told CBS 60 Minutes.

The team found a letter, itself discovered during a previous investigation, which was sent to Otto Frank naming van den Bergh as the person who revealed their address. Frank apparently did not reveal the identity of the person identified as betraying him and his family before his own death in 1980. The team speculated that he may have kept it hidden in order not to "stoke the fires" further of anti-semitism.

"We have to keep in mind that the fact that [van den Bergh] was Jewish just meant that he was placed into an untenable position by the Nazis to do something to save his life," Pankoke said.

"There's no evidence to indicate that he knew who was hiding at any of these addresses,"  he added of the addresses that appear to have been passed on, according to their investigations. "They were just addresses that were provided where Jews were known to have been in hiding."

The Anne Frank House museum says it is impressed by the work that the team has carried out.

"The cold case team’s investigation has generated important new information and a fascinating hypothesis that merit further research," executive director of Anne Frank House, Ronald Leopold, said in a statement.