Anyhow. If they stole the private keys why would they make such a huge withdrawl? I would import those private keys into another bitcoind and make lots and lots of smaller withdrawls over the course of the next few months.
Obviously Zhoutong also has the private keys. He could proceed to move the remaining funds to an uncompromised account and save them.
If you get somebody else's private keys and you want to steal the funds, you need to move them before they find out.