What is the ruling on buying a house from an American bank that first purchases the property and then offers it to the buyer, showing the buyer the contract that was made between the bank and the property owner, bearing only the owner's signature, and informing him that its representative will sign later?

Purchasing a house through the bank via Murabaha is permissible if the Sharia (definition)-compliant conditions are observed. These include the bank taking possession of the commodity and it entering its ownership before selling it to the one requesting the purchase. What the bank deducts upon withdrawal from the transaction is permissible if it is estimated based on the fees incurred by the bank, and it is not permissible for the bank to deduct more than the actual damage incurred. There is no objection to following a trustworthy Sharia board of the bank.