I was told by my gox today that the other account has exchanged my funds for bitcoins and the only thing I can do now is file a police report. What a joke. Bitinstant assured me that my funds had been frozen in the other person's account.
Do it, seriously.
MtGox knows who this person is. A subpoena from police would acquire said data. You could then bring a civil suit against whoever it is to regain your losses, while a district attorney could potentially bring a lawsuit against the person for theft (which it is - you can't just take money from an accounting error if it doesn't belong to you).
If they are even in the same country.
