The sheriff shall return the writ of attachment with the summons if issued at the same time, otherwise, within 20 days after the writ's receipt, with a certificate of the sheriff's proceedings endorsed on or attached to the writ.
Sheriff's Return Of Writ
Mont. Code Ann. § 27-18-604, under Procedure Following Attachment -- Return of Writ.
Mont. Code Ann. § 27-18-604