I don’t remember where I came across it, whether in the virtual world or the solid world. Apparently, someone did the analysis of the paper and the inks and the tools involved in making the diary. The claim was that the paper was not used in Holland, the pen was a ballpoint and the ink was for the ballpoint pen. They were all post-WWII provenence. The conclusion was that Anne Frank did not write the diary, but someone else (apparently an adult male).