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). Notify a third party about a person's death. A death claim letter format for bank is straightforward. Moreover, you just have to submit documents like a death certificate, ID proof, etc. I need to write to several organisations including banks, insurance and mortgager company to inform them of my partners death. Click on the link(s) for the forms you'd like to download.