Most states have statutory redemption to allow the the previous owner to pay the mortgage in full, plus cost, and get the house back, within a certain time period. Califronia for example. An owner can have one year from the auction to get the house back, but only 90 days after recordation.
Even if you recorded, even if you can evict the owner, if the owner can pay back the bank in full plus cost then he has rights to get the house back. The most you can do is to get your purchase money back.
Know the law before you consider buying a foreclosure house.