A letter of testamentary is a courtordered document that grants the executor of an estate the authority to manage the deceased person's assets. We'll need a photocopy of the death certificate to verify the identity and legal residence of your loved one as well as confirm date of death.Any person of legal age (18 or over) may apply for a certified copy of a death record without the cause of death. To close a bank account on behalf of someone who has passed away, you must have legal authority to manage the account.