In order to request an audit of a deceased relative's bank records, you need to consult with an attorney about the situation and retain him or her to write a letter to the bank on behalf of the estate of the deceased relative assuming there is no attorney representing the estate.If there is one or was one, then that attorney should be consulted to investigate your suspicions that something improper may have been going on with respect to his bank accounts and request copies of statements as well as cancelled checks as to his account for a set period of time.