25 CFR § 15.103
How do I begin the probate process?
February 24, 2021
As soon as possible, contact any of the following offices to inform us of the decedent's death:
(a) The agency or BIA regional office nearest to where the decedent was enrolled;
(b) Any agency or BIA regional office; or
(c) The Trust Beneficiary Call Center in OST.