To close a bank account on behalf of someone who has passed away, you must have legal authority to manage the account. Follow the bank's procedures: The bank will likely have you fill out some forms and provide the necessary documents to close the account."Letters of Office" is not really a letter. The affidavit is often coupled with a copy of the death certificate. The affidavit can then be used to complete the distribution of property. The bank will not allow you to close it unless you have a letter of authorization from the probate court. The best way to avoid any issues with accessing the bank accounts of deceased family members is to have a clear and up-to-date estate plan in place. Death certificates are used to close bank and brokerage accounts, file insurance claims, register death with government agencies, etc. The Petition for Letters of Administration is the document that is used when the decedent died without a will. It is often necessary that the property and financial affairs of a deceased person be supervised through a court process.