Sample Letter to Bank Informing the Death of the Account Holder. The death claim letter should be written in the formal letter format.This is to notify the bank that my. (Relationship with deceased). You have to write an application to the bank. Click on the link(s) for the forms you'd like to download. To close a bank account on behalf of someone who has passed away, you must have legal authority to manage the account. Documentation about the account and its owner, including the deceased's full legal name, Social Security number, and the bank account number.