Can you make an offer on a REO that is not listed for sale?

[Heather Taft]

I am looking to buy an attached house in a specific neighborhood. One REO that I was about to make an offer on my agent found out was actually already under contract. There are no other houses for sale here except for new construction, and since I would like to live in the house for a year or 2 then make it a rental I don't want new construction. I've looked over all the houses in the area on zillow and there appear to be 4 REO houses that are not for sale currently (one is a HUD, I'm new to this and not sure how/if that is different). All the houses have been listed for sale and the listing was removed. I am thinking of contacting the previous listing company to see if they can tell me for sure if it is an REO, but if it is not listed as being for sale right now is it possible to make an offer? Any thoughts and advice would be greatly appreciated.