Lawyers can and will hire experts to handle the technicalities, in bitcoin or any other field.
The technicalities of liquidation, not the technicalities of recovering the missing 650,000 BTC!
No, I mean technical aspects of the issue. If it were a theft of chemical formulas they would hire chemical experts, if it was a theft of computer chip designs they would hire chip design experts, etc..
The police in countries like the US and Japan is quite compentent by now in the investigation of cybercrimes. Bitcoin is not more complicated than the things they have already mastered.
On the other hand, the "crowd detectives" who poke at the blockchain so far have made a lot of noise, but have no concrete result to show, have they? In MtGOX or any other theft/scam...
And you really think the Tokyo police has a higher chance of solving the mystery than has the Tokyo police PLUS a restarted MtGox run by (presumably) competent people who have a bigger incentive to solve it?
The police certainly has a better chance than a team of unknown managers who MAY bring in the police (but almost certainly will not).