Yes it was hacked, I was alerted and responded quite quickly but it still got locked down. I am not aware of it being sold unless you have some evidence.
Usually the account hackers aren't the same people that join signature campaigns is why I said that, not going by any particular proof.
It wouldn't be a valid btc address. I once assisted with devcoin which was a completely different now defunct blockchain.
Believe it or not Devcoin is still going:
https://explorer.devcoin.org/If you can sign a message from 12Byy43HThNYsqWLH6fzY2Bxa2JP7Z5wYk or 19piwg8kyW5unDpLjYjbvE6GGvtAfghT8c and it can be independently verified, I'd think that would count.
Good luck.
Oh, BTW, almost nobody who is around now knows who BitcoinEXpress was or the depth of his legend.

The biggest fear to ever grip a budding new altcoin dev.