Here are his answers to piuk's questions.
Do you have a blockchain.info wallet holding the address in question? Yes
If you have a blockchain wallet do you use a public alias the same as your bitcointalk, bitcoin-otc or irc username? No
Do you have accounts on one of the following sites: BTC-e, bitcoin-central or mining.bitcoin.cz? No
Do you reuse the same wallet password on different websites (specifically the above sites)? No
Do you read the BTC-e chat box? No
Does your browser have Java enabled? http://isjavaenabled.com - I have JAVA but I manually choose each time whether to run it
He insists that he is keeping a secure environment and that neither his computer nor strong password were compromised.
Any leads on what could have caused this? Or who the thief is?
Will reimbursing affected users be considered?