P.R. Laws Ap. tit. 32A, § III, Rule 58.4
(a) Notice; delivery. — Upon the filing of the complaint the plaintiff shall forthwith deliver to the clerk joint or several notices directed to the defendants named or designated in the complaint. Additional notices directed to defendants subsequently added shall be so delivered. The delivery of the notice and its service have the same effect as the delivery and service of the summons under Rule 4.
(b) Same; form. — Each notice shall state the name of the court, the title of the action, the name of the defendant to whom it is directed, that the action is to condemn property, a description of his property sufficient for its identification, the interest to be taken, the authority for the taking, the uses for which the property is to be taken, that the defendant may serve upon the plaintiff’s attorney an answer within twenty (20) days after service of the notice, and that the failure so to serve an answer constitutes a waiver to the right to make objections to the taking and a consent to the authority of the court to proceed to hear the action and to fix the compensation. The notice shall conclude with the name of the plaintiff’s attorney and an address where he may be notified. The notice need contain a description of no other property than that to be taken from the defendants to whom it is directed.
(c) Service of notice. —
(1) Personal service. — Personal service of the notice (but without a copy of the complaint) shall be made in accordance with Rules 4.3 and 4.4 upon a defendant who resides within the Commonwealth of Puerto Rico or within the United States or its territories or insular possessions and whose residence is known.
(2) Service by publication. — Upon the filing of a certificate of the plaintiff’s attorney stating that he believes a defendant cannot be personally served, because after a diligent inquiry within the Commonwealth of Puerto Rico the place of residence of the defendant cannot be ascertained, or, if ascertained, that it is beyond the territorial limits of Puerto Rico, service of the notice shall be made on this defendant by publication in a newspaper of general circulation in Puerto Rico once a week for not less than three successive weeks. Prior to the last publication, a copy of the notice shall also be mailed to a defendant who cannot be personally served as provided in this rule but whose place of residence is then known. Unknown owners may be served by publication in like manner by a notice addressed to “Unknown Owners”.
Service by publication is complete upon the date of the last publication. Proof of publication and mailing shall be made by certificate of the plaintiff’s attorney, to which shall be attached a printed copy of the published notice with name and dates of the newspaper marked thereon.
(d) Return; amendment. — Proof of service of the notice shall be made and amendment of the notice or proof of its service allowed in the manner provided for the return and amendment of the summons under Rules 4.8 and 4.9.