AMSTERDAM — Hiding from the Gestapo in a secret annex of her father’s warehouse in Amsterdam during World War II, Anne Frank heard a little knock on the wall. She could not be sure who or what it was, and it frightened her.
She was right to be scared: Just months later, on Aug. 4, 1944, the police discovered the hide-out during a raid and arrested her and seven others living behind a movable bookcase. All but Otto Frank, the diarist’s father, and later the editor of “The Diary of a Young Girl,” perished in Nazi death camps.
Who gave them up has remained a mystery. Now, almost 75 years later, a team of experts led by a retired F.B.I. agent is bringing modern forensic science and criminology to bear in hopes of solving one of history’s most famous cold case files.
“We will put special emphasis on new leads,” said the retired special agent, Vince Pankoke, 59, who is leading the effort. “We need to verify stories as they come in, and we know that is going to lead to further investigation.”
In the search for new leads, he and his team are digitally combing through millions of pages of scanned material from the National Archives in Washington as well as archives in the Netherlands, Germany and Israel.
The use of other modern techniques like forensic accounting, crowd sourcing, behavioral science and testimonial reconstruction may also hold promise of a breakthrough. The team, for example, is carrying out a three-dimensional scan of the original house and using computer models to determine how far sounds might have traveled.
Those techniques may allow them to re-evaluate old evidence — for instance, whether the knock on the wall, described in Anne Frank’s diary, was someone telling those hiding that they were being too loud, or whether it could have been a trap.
Such modern and expensive techniques were not available to the Dutch national police when they unsuccessfully investigated the case in 1948 and again in 1963.
Much is known about Anne Frank’s life during her two years in hiding, thanks both to her famous diary and the accounts of helpers and friends published after the war. But far less is known about the circumstances surrounding the raid on Aug. 4, 1944.
The raid ended her time in the house on the Prinsengracht and precipitated her long and torturous journey to the Bergen-Belsen concentration camp, where she is believed to have died in February 1945.