One potentially problematic issue is that although 40,000 BTC were stolen in the MtGox intrusion, only 20,000 BTC were returned. Although more USD was returned than was stolen ($60,000 more), movements in Bitcoin price since then mean those missing Bitcoins now have a value of ~USD 600,000.
You know that ZhouTong is reading this and hoping daily that no one gets smart and comes after him for the other 20k btc. It's worth $600k now.
Yeah, pretty sure he's responsible. He did it the moment he found out that the source code was leaked (pissed him off, plus gave him plausible deniability).
I don't think he's worried though. Now, if someone goes after Trendon Shavers (and then Sam Theofanopoulos aka HaskKing), then he would start worrying.
BTW, has anyone contacted MtGox about their stance on the bitcoinica funds?