Computer scientists from Xomnia provided the foundation for the Microsoft AI program, which created a virtual picture of where the persons resided in the neighborhood. Complicating the process was the fact that many of the Amsterdam street names had changed since the war. However, the scientists were able to write a program that converted the street names from a current map to a wartime map and then geolocate all of the addresses of the residents and potential threats.1
Xomnia’s offices are in a historic building just off the Prinsengracht, five blocks south of Anne Frank House. The Cold Case Team was invited for a demonstration. The researchers said they were speechless when the visual of the neighborhood appeared on a large wall-mounted monitor. Colored dots representing the various categories of threats, such as NSB members (blue), collaborators/V-people (red), and SD informants (yellow), were so close together that they appeared as one large mass over the greater Jordaan neighborhood. As the visual zoomed in on the streets directly surrounding the Annex, the dots were less dense, but the number of threats was still astonishing. An SD informant named Schuster owned a bike shop a block and a half away from Otto’s business; a collaborator named Dekker, a waiter by profession, whose name the team found on the resistance’s wanted list, lived a few doors down from the Annex; and multiple NSB members resided in the buildings bordering the back courtyard.
After the Cold Case Team’s project was announced publicly at the end of September 2017, Kelly Cobiella, a reporter for NBC’s Today show, traveled to Amsterdam to interview the team. Vince demonstrated the virtual program showing the concentration of threats surrounding the Annex and said that instead of asking what caused the raid, maybe they should be asking how the hiders lasted for more than two years before being captured.
For David Barnouw’s neighborhood theory to be valid, it wasn’t enough that neighbors be fervent NSB members; they would also have to have knowledge that Jews were hiding in the Annex. The team found that some neighbors seemed to know that the Annex was occupied, including those in the businesses in the two buildings on either side of Prinsengracht 263: Elhoek, an upholstery shop at 261, and Keg, a tea and coffee business at 265.
Bep claimed that an employee of Keg asked the staff of Opekta/Gies & Co. about the building’s drainpipes. He wanted to know “if people were staying in the building.” He often worked late at night and heard water flowing through the drainpipes after everyone had gone home. An Elhoek employee said that they sometimes ate their lunch in the wide gutter between 261 and 263 and occasionally heard voices coming from the Annex.2 As Anne mentioned in her diary, the residents were occasionally careless, peeking out of windows and sometimes forgetting to close the curtains.
Yet, assuming that some neighbors were suspicious, it wouldn’t have been an automatic conclusion that the hiders were Jewish. By August 1944, a vast number of Dutch citizens (estimated at more than three hundred thousand) were hiding to avoid being sent to Germany for mandatory work duty or were wanted for escaping from the work duty camps. The occasional sound of voices, the noise of water running, or smoke from the Annex chimney could just as easily have been caused by Dutch citizens in hiding as by Jews. Given the Nazi anti-Semitic propaganda of the time, it seems that some people were willing to betray Jews (one-third of Jews in hiding were betrayed). But they were less willing to betray Dutch citizens who were refusing to work in the enemy’s country, which would only prolong the war, which, by the summer of 1944, the Germans were clearly losing.
It was important for the Cold Case Team to determine what could actually be seen and heard from the buildings whose rear windows faced the shared courtyard, which was roughly two hundred feet long (two-thirds the length of a football field). Vince wanted to conduct a 3D laser and audio scan of the courtyard, but there were too many buildings involved and it would have been outrageously expensive. Instead, he and Brendan Rook, the former investigator with the International Criminal Court in the Hague, used the gumshoe method.
They approached the Anne Frank House and asked for access to the roof of the administrative offices and museum, which occupy the corner of the block next to the Prinsengracht 263 address. The Anne Frank House was entirely cooperative and pointed out the stairs to the roof. Luckily, most of the buildings surrounding the courtyard are essentially the same as they were during the war, except for the one they were standing on. From there they had a bird’s-eye view of the entire courtyard but only a side view of the Annex. It immediately became clear that the buildings on the Prinsengracht to the left and right of the Annex did not have a view of its rear-facing windows. Only a select number of windows in buildings on Westermarkt, Keizersgracht, and Leliegracht possessed a line-of-sight view of the Annex.
Certain views would have been further obscured by the large chestnut tree that once stood behind the Annex; Anne often referred to it in her diary. (In 2010, the almost one-hundred-year-old tree was felled by high winds, although it still lives today. Chestnuts from the tree were rooted, and the saplings were planted all over the world in Anne’s memory.) Looking at time-period aerial photos of the courtyard during the summer, it’s clear that the tree’s foliage would have almost completely eliminated a view of the Annex from most of the buildings on the Keizersgracht side of the courtyard.
Because their rooftop perspective didn’t allow them to see the windows of the Annex, Vince and Brendan searched for another location. A building directly across the courtyard from the Annex on the Keizersgracht, now a very popular comic book store, seemed to offer the best vantage point. When they explained to the owner what they needed, he was immediately accommodating. He said he’d inherited the building from his father and lived on the floors above. They were very welcome to see what could be observed from the upper windows. As they were about to climb the stairs to the top floor, he told them, with some embarrassment, that a few family members had been pro-Nazi during the war.
Vince and Brendan sat at the owner’s bedroom window, staring across the courtyard at the Annex and wondering what could have been seen and heard while it was occupied by the hiders. Today, all the Annex windows are covered by shutters except for the lone window of the attic where Anne, Margot, and Peter used to retreat to escape their parents. From their vantage point the two men could see the steeple of the Westerkerk church, its bells still loudly ringing on the quarter hour as they had during the war. Also visible was the stump where the chestnut tree had once stood. The courtyard was mostly empty of people, with the exception of a few residents watering plants and several workers doing a patio renovation at the far end of the courtyard.
From their brief survey, Brendan and Vince were able to draw several conclusions: Even though people who had a direct view of the rear of the Annex might have been able to detect movement inside, it would have been very difficult to identify whether it was caused by workers or residents, Jews or non-Jews, especially at night with the air-raid blackout curtains in place. In addition, because the courtyard is surrounded by mostly brick and block buildings, sounds would have bounced around and deceived listeners as to their point of origin.