A team that included retired U.S. FBI agent Vincent Pankoke and about 20 historians, criminologists and computer specialists identified a relatively unknown figure, the Jewish notary Arnold van den Bergh, as a leading suspect in revealing the hiding place.
Some other experts stressed that the evidence against him was not conclusive.
The memo said Van den Bergh had access to addresses where Jews hid as members of Amsterdam's Jewish Council in wartime and had passed lists of such addresses to the Nazis to save his own family.
Twisk said only four of the first 32 names remained after the investigation, with Van den Bergh as the lead suspect.
Investigators confirmed that Otto, the only member of the family who survived the war, was aware of the note but never chose to talk about it in public.
Van Twisk speculated that Frank's reasons for keeping quiet about the allegation were likely that he could not be sure that it was true that he did not want information published that could feed further anti-Semitism, and that he did not wanted Van den Bergh's three daughters to be blamed for something their father could have done.
Otto "had been to Auschwitz," Van Twisk said. "He knew that people in difficult situations sometimes do things that cannot be morally justified."
While other members of the Jewish Council were deported in 1943, Van den Bergh was able to remain in the Netherlands. He died in 1950.
Historian Erik Somers of the Dutch NIOD Institute for the Study of War, the Holocaust and Genocide praised the comprehensive study, but was skeptical of the conclusion.
He questioned the centrality of the anonymous note in the arguments for Van den Bergh's responsibility, saying that the team made assumptions about wartime Jewish institutions in Amsterdam that are not supported by other historical research.
According to Somers, there are many possible reasons why Van den Bergh was never deported, as "he was a very influential man."
Miep Gies, one of the family's helpers, kept Anne's diary until Otto returned and published it for the first time in 1947. It has since been translated into 60 languages and captured the imagination of millions of readers worldwide.
The Anne Frank House Foundation was not involved in the cold case investigation, but shared information from its archives to help.
Director Ronald Leopold said the research had "generated important new information and a fascinating hypothesis that deserves further research."
Using modern research techniques, a master database was compiled with lists of Dutch collaborators, informants, historical documents, police records and previous research to uncover new clues.
Dozens of scenarios and locations of suspects were visualized on a map to identify a traitor, based on knowledge of the hiding place, motive and possibility.
The results of the new research will be published in a book by Canadian author Rosemary Sullivan, "The Betrayal of Anne Frank," due out Tuesday.
The director of the Dutch Jewish organization CIDI, which fights anti-Semitism, told Reuters she hoped the book would provide insight into wartime conditions for Amsterdam's Jewish population.
"If this becomes 'the Jews did it', it would be unfortunate. The Nazis were ultimately responsible," said Hanna Luden of CIDI.