How did you get his personal information?

It seems to me that a hypothetical someone involved with credit card fraud and laundering of funds through LR or suspicious bank accounts (Liu Haipeng) would communicate with you only through his internet alias. You already admitted you've never met this individual in person, only on the internet. What reason would he have to tell you his name, his wife's name, and their bank accounts and addresses? If he were to provide you business advice about anti-fraud measures, the most likely way for him to request payment for his services would be to tell you his AliPay account, not his family's addresses and bank account numbers.

That's the hardest part to believe about this hypothetical Chen Jianhai.

Its plausible that a random someone would verify that info@bitcoinica.com is a LastPass account, and also plausible that they would try the API key as the password. If it were a random thief there would be no coincidence. But for that same someone to be your previous "business associate" who also has your stevejobs gmail password, well that's a heck of a coincidence. Unless you were to claim that you also mentioned to this person that you use LastPass, but you never did.