Mike Daudt could help with this. Alternatively, the Bar has a project that can assist homeowners with issues like this. You can find more information at http://www/wsba.org hope this helps.
A quiet title lawsuit is the way to proceed. You can check to see if the Deed of Trust had been assigned. You would need to sue the current holder of the Deed of Trust. You may have to investigate how Chase took over WAMU.
An attorney representing you would need to know several things about the loan, such as the last time a payment had been made (to see if the statute of limitations had run) and if any arrangements had been made with WAMU post bankruptcy