Who betrayed Anne Frank and her Family.

I recently read a book called the Secret Life of Otto Frank,by Carl Ann Lee.An interesting read.In the book Lee states her belief that the betrayer of the Frank family was a man by the name of Toni Ahlers.While Lee gives some very convincing evidence to support Ahlers as the betrayer,I do have one doubt in particular.Lee states that Ahlers had evidence that Otto Franks company was doing business during the war with the German occupiers and that Ahlers was blackmailing Otto Frank to keep this quiet.Here is the problem for me;Ahlers lived until the year 2000 ,again stated in Lee,s book, that he[Ahlers], was jealous of Otto Frank as a result of the fame of the Anne Frank diary.Why then did Ahlers not say publicly that he believed Otto Franks company,Opetka,had collaborated with the German Occupiers?
Anyone interested in this can view the report made by the Netherlands Institue for War Documentation on their website.It does make very interesting reading.