Sample Letter to Bank Informing the Death of the Account Holder. The death claim letter should be written in the formal letter format.You'll need the person's Social Security number and certified copies of their death certificate for most agencies and programs. Social Security and Medicare. Give application to the bank or treasury as the case may be informing passing away of the Pensioner. To close a bank account on behalf of someone who has passed away, you must have legal authority to manage the account. Click on the link(s) for the forms you'd like to download. Download Ohio Affidavit of Death template, modify and send for signing using BoloForms Signature. Here, you'll find a high-level outline of what happens to a bank account when someone dies. 1. Establish your authority.