Mont. Code Ann. § 72-3-306
(1) If it appears by the petition or otherwise that the fact of the death of the alleged decedent may be in doubt or on the written demand of any interested person, a copy of the notice of the hearing on the petition must be sent by certified mail to the alleged decedent at the alleged decedent's last-known address. The court shall direct the petitioner to report the results of or make and report back concerning a reasonably diligent search for the alleged decedent in any manner that may seem advisable, including any of the following methods:
History: En. 91A-3-403 by Sec. 1, Ch. 365, L. 1974; amd. Sec. 3, Ch. 516, L. 1975; R.C.M. 1947, 91A-3-403(2); amd. Sec. 2329, Ch. 56, L. 2009.