Article 1004 of Civil Code

1 - Upon maturity of the debt, the mortgagee may levy execution against the mortgaged property in the hands of its third-party possessor after serving him notice to pay the debt, unless the possessor elects to discharge the debt, purge the property of the mortgage, or relinquish it. 2 - A third-party possessor of mortgaged property is any person to whom ownership of that property, or any other mortgageable right in rem over it, has passed for any reason other than inheritance, without being personally liable for the debt secured by the mortgage.