Now: which police? You mean there's no police force, no traceability whatsoever in the beautifull bitcoin world? Nodoby will ever run after the bad guys? Is at least anyone sure that Mt. Gox Ceo hasn't fled with the stolen coins in a pocket? Too bad there's no state to guarantee anything there.
So I'll invent something new! For a small amount collected on each transaction, I promise I shall setup "bitcoin cop". Of course its use will be mandatory for all bitcoin users and enforced through closed source addons to the free client. And centralized too.
It won't cost much! I accept dollars or Euros to provide this service. Thanks for your attention, and your money.
P.S.: do not worry for all those cumbersome extradition and cross-border investigation procedures: bitcoin world does not care, neither do we! And send me the money, please, a modest 10% transaction feee will provide insurance : firstname.lastname@example.org