The first thing I would suggest is to call the auction company listed in the advertisement.
If there is no auction company, then call the Trustee or law firm handling the foreclosure.
They will tell you if it sold to a third party (public buyer) or went back to the lender.
It's a lot less hassle than jumping through the hoops with a realtor, who will try to sell you something else, when all you wanted was the answer to simple question.
Please don't think I am bashing realtors, they have their place but its so much easier to pick up the phone and go right to the source for the answer to a simple yes or no question.