It's embarrassing for the Tokyo Metropolitan Police that they haven't cracked this case yet. They're one of the biggest police departments in the world and have extensive resources. Yes, their in-house computer crime department is new, but they could draw on expertise at the national level or from outside Japan.
I read a book recently that went into some detail about tokyo police's methods regarding a series of murders in the 1990s/2000s. In that account at least they didn't seem very compentent in their investigative skills - they were largely focused on getting confessions from people. Probably not relevant to the MtGox case.
