Landlord blackmail

I live in a rented house I have leased for 2 1/2 years. in june the house went into foreclosure. We offered to buy it in a short sale, the owner consented and accepted our offer. Six months later, he has not complied with paperwork requestd from him from the bank. Through this whole process we have continued to pay the rent. These last 2 months, we gave the rent checks to the attorney handling the short sale with instructions, he turns in the papers, you release the checks. The owner is now threatening to put the house back on the market, and stated he would not comply with the bank, unless we give him the checks. Can he legally do this being that there is a signed purchase agreement, and do we have any legal recourse?

I live in a rented house I have leased for 2 1/2 years. in june the house went into foreclosure. We offered to purchase the property through a short sale and the owner consented. We signed a purchase agreement and turned it in to the bank. Six months later, however, he has yet to comply with paperwork the bank requested to complete the short sale. Through this whole process we have continued to pay our rent eventhough we no longer had a lease, it terminated in August. Time is very limited. If he does not turn in the paperwork, and the bank forecloses we lose the opportunity to purchase this property we have lived for 2 1/2 years, plus the lease money. Can he legally withhold information from the bank being that there is a signed purchase agreement, he consented to the sale and do we have any legal recourse?