Just a thought, if he was @darthknight, would he really have spelled bittrex as "bittrix" when routing the Steem powerdown before Justin froze things? I have no idea about what other info you have, but the "i" is nowhere near the "e" on any keyboard, so I'd lean towards that account being unrelated. Any normal crypto user knows how to spell Bittrex from years of experience. Worth the consideration.