Otto then made a second visit to the prison to interview Gezinus Gringhuis. He made a notation to that effect in his agenda on December 6, 1945, along with the name Ab. That likely refers to Otto’s close friend Abraham “Ab” Cauvern, whose wife, Isa, worked as Otto’s secretary.
Otto was clearly hoping to have his case taken up quickly by the POD, but in 1945 he was just one of 5,500 survivors returning from the camps. Nothing happened. It wasn’t until June 11, 1947, almost two years later, that he next visited the Bureau of National Security in person. Again nothing. Then, after a conversation with Otto, on July 16 Kleiman sent another letter to the Political Investigation Department （Politieke Recherche Afdeling; PRA） （the POD had been renamed in March 1946 after the Allied military forces had handed power over to the civil administration）。 He asked, on behalf of Otto and himself, that the case be “addressed again.”4
On January 12, 1948, three and a half years after the raid on the Annex, Police Brigadier Jacob Meeboer opened an investigation into the warehouse manager, Willem van Maaren, the only person ever officially investigated as the betrayer. Brigadier Meeboer interviewed fourteen people, among them the helpers Johannes Kleiman, Miep Gies, and Viktor Kugler but not Bep Voskuijl;* the Dutch detectives Gezinus Gringhuis and Willem Grootendorst; Johannes Petrus van Erp and Dr. Petrus Hendrikus Bangert, both of whom knew Van Maaren; the other warehouse worker, Lammert Hartog, and his wife, Lena; and finally, Van Maaren himself. Despite Kleiman’s expression of shock in his July letter that Karl Silberbauer had never been brought over to the Netherlands for questioning, seeing that he had “played an important role in the apprehension of ‘Jewish and other absconders,’”5 Silberbauer was not called to testify. Nor was Otto Frank, probably because he’d already told the police that he and his family had been in hiding in the Annex well before Van Maaren was hired and he did not know the man.
Brigadier Meeboer’s official report begins with Kleiman’s testimony, in which he gives a detailed account of the raid and also outlines Van Maaren’s questions and suspicious behavior. Shortly after he was hired, Van Maaren asked the staff about someone being in the stockroom after hours. He’d found a wallet on a table in the stockroom, where Van Pels must have forgotten it during one of his nightly ventures into the warehouse. Van Maaren presented the wallet to Kugler and asked if it was his. Kugler reacted quickly, saying that, yes, it was his and he’d forgotten it the night before. The contents of the wallet were intact, except for a missing ten-guilder note.
Kleiman explained that Van Maaren certainly knew of the existence of the Annex. He’d seen it when Kugler had sent him to fix a leak in the roof, and in any case, a back annex was a feature of many of the narrow buildings in the area. There was also a door at the back of the warehouse opening onto the courtyard. A man as curious as Van Maaren would likely have gone outside; from there, he could see the entire Annex attached to the building. It would have been only normal for him to wonder why the large “appendage” was never mentioned by anyone or used for business purposes. And he would have asked himself where the access to the Annex was located, since there was no clear indication of an entryway. Absent an obvious entrance, he would likely have suspected a concealed door.
Kleiman explained to Detective Meeboer that they would come across pencils balanced on the edges of desks and flour strewn onto the floor, clearly placed there by Van Maaren to confirm his suspicion that people were in the building after hours. Van Maaren once asked Kleiman whether a Mr. Frank had worked in the building, implying that he was conducting his own investigation. Everything suggested that Van Maaren surmised there were people living in the Annex.
Kleiman reported that after the raid on August 4, Opekta’s accountant, Johannes van Erp, visited Dr. Petrus Bangert, a homeopathic doctor, and mentioned that the Jews hiding at Prinsengracht had been arrested. The doctor asked if the address was 263. He said he’d known for about a year that there were Jews in hiding at that address. When Van Erp told that to Kleiman, apparently Kleiman responded that Van Maaren must have been the source of the information since he was a patient of the doctor.
When Dr. Bangert was interrogated, however, he insisted that Opekta’s accountant was mistaken. He’d never said any such thing, he said, and after he checked his patient records, he claimed that Van Maaren had become his patient only on August 25, 1944, three weeks after the arrest. Was that accurate or simply an evasion? It was 1948, three years after the war ended. Everyone wanted to wash their hands of the catastrophe and get on with the peace.