There's another characteristic of a stalking horse bid: they document that bid in the court records letting everyone, including the other bidders, the creditors, the judge, and the public, know about it.
For this bankruptcy, they documented the purchase price, $4.34M for the assets. That's what happened.
Do you really believe someone bought your stock over 6 years ago without telling you? If you do, please turn your investments over to a competent investment advisor before you lose everything.