During a trip to Amsterdam in the spring of 1963, Dutch friends told Wiesenthal that he should not be searching for Silbernagel but rather for Silberthaler, the name Miep had invented. Then he had a fortuitous meeting with Ynze Taconis, the head of the National Criminal Investigation Department （Rijksrecherche） regarding his investigation. As Wiesenthal was about to leave, Taconis handed him what he called a little “travel literature.” It was a photostat copy of a 1943 directory of the SD in the Netherlands with about three hundred names in it. On the plane back to Vienna, Wiesenthal started flipping through the directory, looking for Silberthaler. He never found it, but running his finger down the list of forty or so IV B4 members’ names, he came to the common Austrian name “Silberbauer.” Elated, Wiesenthal finally had his man—or at least his last name, since the roster did not contain first names.6
It was now an astonishing six years since he had come up with the idea of tracking down the SD man. Known for his searches for Josef Mengele and his tracking down of Adolf Eichmann, he would have been the first to admit that Silberbauer was not a high-ranking Nazi. His goal was not so much to punish him as to get him to admit to the arrest of Anne Frank and her family. In early June 1963, he provided the information he’d gathered on Silberbauer to Dr. Josef Wiesinger, his contact at the Austrian Federal Ministry of the Interior responsible for war crimes investigations.
At that point it was not clear if Silberbauer had even survived the war. For the next five months, Wiesenthal regularly contacted Wiesinger to learn if there was any progress in identifying and locating the Silberbauer on the list. He was always met with the same response: “We are working on it.” The last such comment was in October 1963. What Wiesenthal didn’t know, and the Cold Case Team discovered in an Austrian Federal Ministry of the Interior report dated August 21, 1963, was that the Austrian authorities had already identified, located, and interviewed Silberbauer. They just weren’t telling Wiesenthal.
The team learned from the report that Inspector Karl Josef Silberbauer, an employee of the Vienna police, was quietly summoned before a Ministry of the Interior inquiry panel. During the interview he admitted to having been assigned to the Amsterdam SD, stationed there from November 1943 until October 1944, when he was injured in a motorcycle accident. He confirmed having worked under Willy Lages and Julius Dettmann as well as receiving reward payments for the capture of Jews in hiding. He also admitted to never having mastered the Dutch language and needing a translator to conduct interviews. Most important, he confessed to having been present at the arrest of Anne Frank and her family.
In doing a background investigation on Silberbauer, the team learned that after the war, in April 1945, he returned to his native Austria, where he ended up serving a fourteen-month jail sentence for using excessive force against Communist prisoners prior to his assignment in Amsterdam. After his release he was recruited by the West German Federal Intelligence Service （the Bundesnachrichtendienst; BND） and, according to a Der Spiegel report, worked as an undercover operative. His past membership in the SS served to blind targeted neo-Nazis to his changed loyalties.7 After his time with the BND he was hired by the Vienna police, where he rose to the rank of inspector.
On November 11, 1963, nearly three months after Silberbauer provided his initial statement, Wiesenthal read the news in a headline of the Austrian newspaper Volksstimme: “The Man Who Betrayed Anne Frank.”8 It seemed that someone within the Vienna police department had leaked the story to the local newspaper. The world press descended on Vienna. They also immediately requested comments from Otto, Miep, Bep, Kugler, and even the formerly accused, Willem van Maaren. Many followers of Anne’s story and even its participants thought that finally, now that the SD man who led the Annex raid was located, he would reveal the name of the betrayer.
Probably feeling both outraged and hurt, Wiesenthal immediately penned a letter to Dr. Wiesinger, reminding him that he was the one who had provided the name “Silberbauer” and requested a photo that he could send to Otto Frank for identification purposes.9 To preserve their relationship, Wiesinger eventually told Wiesenthal that he’d been ordered by his superiors not to inform him that they’d found and interrogated Silberbauer.
Based on the text of his letter, Wiesenthal still had no idea that Otto and the other witnesses had known Silberbauer’s name all along. But one week after he sent the letter, he likely learned the truth. In one of his interviews after the news broke, Otto admitted to the Amsterdam newspaper Het Vrije Volk that he had known all along that Silberbauer was the man who led the raid. He further commented, “I have never had contact with Mr. Wiesenthal in Vienna. The reason why he wanted to have Silberbauer in particular is, therefore, a riddle to me.”10 In one of her interviews, Miep also confirmed that she had known Silberbauer’s name but had not revealed it because Otto had asked her to use a fake name.11