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An NSB (i.e. Dutch Nazi Party) member, who had a violent criminal record, liked blackmail, and loved being the focus of attention. On 18 April 1941, Tonny appeared at the office and confronted Otto with an accusing letter to the NSB about him and, surprisingly, gave it to him. Otto thanked him with some money. After the war, Ahlers pursued Otto, apparently wanting him to vouch for his character to counter charges made against him. Otto's good words did not count more than the evidence, though: Ahlers was jailed for having betrayed Jews in hiding. I think it is also a safe assumption that Otto was not the only person during the war who gave him hush money. Date of death: 4 August 2000. (HLOF p. 58-9, 128-9, 187-192, 205-7, 223, 283-5, 319, 324, 333; The NIOD's early 2003 report, "Who Betrayed Anne Frank?" (190K DOC file) has a good deal of details about him, correcting some errors in HLOF; Anne Frank researcher)
Note: after the war and jail sentence, Ahlers had a mysterious source(s) of income. One possibility is that he was blackmailing some people. I am unconvinced that he successfully blackmailed Otto Frank. For one thing, Ahlers didn't have much bad information to pin on him. Further, Ahler's later allegations fit the picture of Otto not complying (i.e. Ahlers was following through on his threats). Specifically, after Anne's diary achieved world renown, Ahlers started writing to places that he had betrayed Otto, with innuendo against Otto. When no one took him seriously, he let the matter drop. Even his wife and kids didn't believe him: they knew him all too well. HLOF p. 281-5
