Mont. Code Ann. § 72-15-107

Whenever a person dies in any county of this state and an administrator has not been appointed to take charge of the person's estate, the public administrator of the county, prior to the issuance of letters of administration, has authority to make a written demand upon any person, firm, bank, or corporation that the public administrator believes holds or has in its possession or control any money, evidence of indebtedness, or other personal property or that owes to the deceased person any money requiring that entity to furnish to the public administrator a written statement, under oath, showing the amount of money or the evidence of indebtedness or personal property of the deceased person held by it fully describing the evidence or property and the total sums of money, if any, due from it to the deceased person. Upon receipt of the written demand, the person, firm, bank, or corporation receiving the demand shall immediately furnish the statement, under oath, to the public administrator.