If it appears that any judgment has been obtained in a suit at law for the money demanded by such complaint, or any part thereof, no proceedings shall be had in such case, unless to an execution against the property of the defendant in such judgment the sheriff or other proper officer has returned that the execution is unsatisfied in whole or in part and that the defendant has no property whereof to satisfy such execution except the mortgaged premises.
Neb. Rev. Stat. §§ 25-2143