I just wonder how long a tip like that will take to trickle thru the Japanese system before anything would be done. likely there is no precedent for something like this either. as much as people call bitcoin a currency it is really not and is not subject to the same financial standards and laws. for instance could i get that same agency involved if someone stole all my wow gold it is effectively the same concept and is a "digital currency" as well.
there is a huge grey area here and it will likely be addressed in the coming months. just my 2 cents

This was an area of some discussion. However, there are several sections that may apply. I'm sure that the lawyers will be sorting much of this out for years (in general, not specific to this case), but the "low hanging fruit" here seems to be dealing in deposits in a foreign currency for investment purposes that may lose value owing to fluctuations in traditional forex markets, even though in this case they were unlikely to be converted into yen.