There should have been proces-verbalen （police reports） that could have provided critical details on collaborators, but according to Jan Out, a policeman working as an archivist for the police, due to lack of space and money, the records from that period were all （one might say conveniently） destroyed. What did survive were the daily police reports kept by every precinct in the city. Anyone who was arrested or otherwise involved in an incident that required police or even came into the precinct to report something was noted in the record book, often together with the officer involved. Twelve-year-old Anne Frank is in one of the books, reporting the theft of her bicycle on April 13, 1942, a little less than three months before the Franks went into hiding.
In the mid-1990s, the archivist Peter Kroesen discovered daily police reports from the period 1940–1945 among a huge batch of files about to be destroyed. He saved them by smuggling them to a safe storage location. （These files, which can be viewed but not scanned, are among the most visited at the Amsterdam City Archives.） The Cold Case Team painstakingly reviewed the police reports for all incidents and calls for service originating from the Annex neighborhood, looking for any clues that might shed light on who or what could have initiated the raid.
The team of researchers assigned to the various portions of the Residents Project entered the information into a database and then uploaded it to the AI platform so they could cross-reference the names on residence cards, NSB membership lists, SD informant lists, known V-Men and V-Women, and daily police reports, as well as purge files and social services files, focusing on Prinsengracht and the surrounding streets: Leliegracht, Keizersgracht, and Westermarkt.
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.