It doesn't matter whether BTC itself is regulated right now for the issue at hand. What matters is that MtGox is regulated.
Note that in the scenario where I go through the police, it is actually possible to prove everything (which is the main reason money laundering via bitcoin does not happen en masse yet), as long as the investigation gains access to MtGox data, which is what would happen in Germany, but before that I could try it in Japan.

Not that I will actually go to the police myself, I don't have time for that
Any lawyer interested to try a BitCoin case, do a good deed and make some cash?