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.
Occasionally the Cold Case Team was contacted by people who had new theories about the betrayer of Anne Frank that related to the neighborhood. One of the more interesting came from Arnold Penners, a retired physiotherapist in Amsterdam-Noord. In 1985, he said, he’d had an elderly woman patient—he didn’t remember her name, only that it began with a B—who claimed she’d been living on the Prinsengracht only a few houses down from 263 and had witnessed the arrest. The team became very excited at this news since it would be the first and only known witness statement regarding the arrest by someone other than the helpers, Jan Gies, and Willy Kleiman.
According to the woman, it was a beautiful day. She was hanging out the window of her house looking down into the street when she saw a truck coming from the Rozengracht. It stopped in front of number 263, and from the front of the truck a German officer and a man she recognized as one of Gies & Co.’s warehousemen, Lammert Hartog, stepped out. Some German soldiers and Dutch police leapt from the back of the truck, and the soldiers blocked the road in both directions. Hartog pointed upward at number 263, and the other men entered the building. Sometime later she saw them coming out with the prisoners from the Annex. Lammert Hartog walked over to the other side of the canal and shouted something anti-Semitic at the prisoners. When the truck started moving, she noticed a small group of women standing by the road and spotted Hartog’s wife, Lena. Lena also shouted something anti-Semitic and banged the side of the truck as it drove past.