Liability of banks for an alleged illegal mortgage

Hi! Happy New Year to All! To all our lawyer brods, have a question: Do I have to file a criminal case against a bank for mortgaging a property when in fact it is annotated in the title that someone has an adverse claim on the property? Facts are as follows: The title of the real property of the complainant went into some allegedly illegal transfer (3 yung napasahan ng property) due to an alleged forged deed of sale which started it all. on the 3rd transfer, the complainant filed a complaint for estafa thru falsification of public documents against the three respondents. The case is pending before the QC court. Subsequently complainant found out that the property was mortgaged to a bank and that the 3rd person in possession of the title failed to pay his loan with the bank. SO now the property was foreclosed. The complainant informed the counsel of the bank that he is the true owner of the property. Complainant found out that the bank accepted the property as collateral without having a guarantor and without conducting further investigation as to the ownership of the property, when in fact it was annotated in the back of the title that there was an adverse claim and that a criminal case was filed on the persons responsible for the illegal transfer. Complainant is thinking of filing a similar case (estafa thru falsification) against the 2 bank officials who signed the mortgage agreement. Tama ba na i file ung criminal case na yun? Or dapat civil case lang (annulment of mortgage? ,etc.) Please help. I read similar cases pero di naman criminal case yung sinampa sa bank eh. Will appreciate your opinions. Thanks and a blesses new year to all!