25 CFR §15.104

1. (a)Yes. You must provide us with a certified copy of the death certificate if a death certificate exists. If necessary, we will make a copy from your certified copy for our use and return your copy.
2. (b)If a death certificate does not exist, you must provide an affidavit containing as much information as you have concerning the deceased, such as:
   1. (1)The State, city, reservation, location, date, and cause of death;
   2. (2)The last known address of the deceased;
   3. (3)Names and addresses of others who may have information about the deceased; and
   4. (4)Any other information available concerning the deceased, such as newspaper articles, an obituary, death notices, or a church or court record.