The person who sold you this account (if it was in fact sold) most likely hacked it.
This is speculation though and doesn't add any value to the feedback system. It only taints the collectible (the account).
It has 2 posts from the original owner which does not have any ties to any business, organization or anything that could be used to leverage the account pretending to be the original owner.
I have no problem with what you're trying to do. My only gripe is that you are focusing on a guessed hacking accusation from the seller instead of leaving feedback that accurately describes what has happened.
I do not dispute that this is a bought account. I am more than fine with people marking it red to warn users not to trust or trade with this account (as they should). The guessing should be left out though.