Even though the Van den Bergh theory was clearly the most likely, Vince said he had played the devil’s advocate with all of the key points over and over. Time and again, Van den Bergh emerged as the most likely perpetrator. In fact, it was the only theory that explained Otto’s behavior and the statements he and Miep had made over the years. But before officially concluding anything, Vince wanted to conduct one more test: he wanted to present all of the evidence in the form of a closing argument to Pieter in a manner similar to the way prosecutors present a case at the conclusion of a trial.
Vince and Pieter often found themselves alone in the office after everyone else was gone. “I was sitting at my desk, and Pieter was sitting in Brendan’s chair with the pictures of the SD IV B4 Dutch detectives over his shoulder,” Vince recalled. “I began by reminding him of Melissa Müller’s statement that ‘this is not so much a case unsolved as a secret well kept.’” Then he listed Otto’s actions as they related to the Van den Bergh theory.
The fact that Otto survived the horror of the concentration camps demonstrated his profound will to live. Obviously, he was sustained by his determination to be reunited with his wife and daughters. But his return to Amsterdam was overshadowed by his uncertainty about their fate. To those who encountered Otto at the time, he seemed to be a man purged by fire, walking through Amsterdam as though in a strange dream, searching for news of his children. Finding out that he was his family’s sole survivor must have sent him to a very dark place. Vince hypothesized that Otto’s grief had eventually turned into a mission to find the people responsible for the Annex raid, although his motive was not vengeance; he was seeking accountability and justice. There is evidence of his saying this, both in a letter he sent to his mother in November 1945 and later in the CBS documentary Who Killed Anne Frank?, which aired on December 13, 1964.
But, Vince asked, was it also possible that his search for justice was influenced by the anonymous note he’d received naming Van den Bergh as the betrayer? The note must have occasioned endless questions. Why would Van den Bergh, a fellow Jew, pass on his address to the SD? How did he get the Annex address? What did he receive in return for providing the addresses? Otto must have asked himself if he should go to the authorities with the allegation. He certainly conducted his own investigation. He, Kugler, and Kleiman went to the Bureau of National Security as early as November 1945 to review photos of the Dutch detectives who’d worked for IV B4. Then he, Kugler, and Kleiman went to Amstelveenseweg prison to confront the two men they’d identified as having participated in the raid. Otto even returned with his friend Ab Cauvern to question Detective Gringhuis, and that time he pointedly asked about Van den Bergh. He also made numerous visits to the Dutch collaboration authorities between 1945 and 1948, although some of the visits probably dealt with the inquiries concerning Tonny Ahlers and Job Jansen.
At the time, it must have been a tough decision for Otto not to inform Kugler or Kleiman about the anonymous note, for they, too, were victims of the betrayal and ended up in internment camps. Perhaps Otto thought that if he did tell them, they would immediately contact the collaboration authorities, which he was not prepared to do.
Otto was closer to Miep than to any of the other helpers. Vince concluded that it would have made sense for him to inform her of the note’s contents, and he probably did so sometime after the 1947–48 investigation and well before the Schnabel book came out in 1958. Reading Miep’s statements to investigators in 1947, it’s clear that she still believed Van Maaren was the culprit, but when she was interviewed later by Schnabel, she was much more circumspect. By that time, she and Otto knew about Van den Bergh.
Otto was making inquiries about Van den Bergh between late 1945 and 1949. He would have known that, during that time, Van den Bergh was being targeted by the Jewish Honor Court for his membership on the board of the Jewish Council. This poses a question: Why didn’t Otto present the contents of the note to the court, since it was Jews judging the actions of Jews, something quite different from the collaboration investigations? Perhaps as he followed the court’s proceedings, Otto was waiting for others to come forward with similar anonymous notes as the tipster had referred to Van den Bergh’s list of addresses. Since that did not happen, Otto may have felt uncertain about how to proceed.
After the Jewish Honor Court’s verdict, which was only mildly punitive to Van den Bergh, Otto might again have considered the consequences of revealing the existence of the note. And if he learned that Van den Bergh was suffering from cancer and would soon leave Amsterdam for treatment in London, would he likely have pursued the case?
In the years following Van den Bergh’s death, the astonishing success of Anne’s diary, play, and movie dominated Otto’s life. By staying busy and focusing on other things, it was probably easier to assign the uncertainty concerning the betrayer of the Annex to the recesses of his mind. The world knew the story of the Annex only up until Anne’s last entry, made on August 1, 1944, and so far, there was no public curiosity regarding the betrayer. But that changed in the mid-1950s, when Otto was convinced by the German publisher of the diary to collaborate with Ernst Schnabel on a book that would tell the full story of the Annex before, during, and after the raid.
Such a book might help dispel the rumors that Anne’s diary was fake. By agreeing to collaborate on the book, Otto and the helpers hoped to prove to the world that Anne Frank was real, the diary was real, and so were the people whom Anne wrote about. But Schnabel’s book also provided information about the raid and clues as to who might have caused it, thus unintentionally opening a Pandora’s box. Otto had asked Miep to disguise the name of the SD officer Silberbauer. Why? The only reasonable explanation is that he feared that Silberbauer might know who made the anonymous phone call and might point to Van den Bergh—and by now Otto did not want his name revealed.
Sometime just prior to or immediately after Schnabel’s book was published, Otto decided to take a bold but very risky step about the anonymous note he’d kept secret all these years. He knew that Schnabel’s book contained information that would cause the news media, along with readers, to question him or the others about the raid. Clearly, he decided not to destroy the note. Instead, he found someone to whom to entrust it. In case he were ever confronted about its existence, he could truthfully respond that he no longer had it. One might have expected him to choose Kleiman, but he gave the note to his friend, the notary Jakob van Hasselt, who also happened to be a friend and business contact of Van den Bergh.