Really, based on what? His claim that they received stolen coins, backed by absolutely zero evidence?
If it was true that he had stolen coins, they'd be selling for cheaper than MtGox. They're not! Asking price at coinexchanger ridiculously high (not even counting the withdrawal fee). Conclusion: coinexchanger = troll.
I mentioned this in another thread, but basically, the fees don't matter to someone looking for an anonymous, easy and shady place to unload for quick and easy cash.
To be honest, CoinExchanger is starting to look like the only place the hacker could go if he wanted to avoid the wrath of the community (since CoinExchanger is full on douchebag).
But the fees matter to the buyer. That's why we have reports of a couple of folks who bought possibly stolen coins from cryptoXchange - because they were the cheaper than mtgox.
Until coinExchanger can be confirmed to be selling coins below mtgox price, anyone investigating him is wasting their energy on an obvious troll who should just be ignored.