● Section 14, Rule 14 (on Summons) of the Rules of Court provides:

SEC. 14. Service upon defendant whose identity or whereabouts are unknown. In any action where the defendant is designated as an unknown owner, or the like, or whenever his whereabouts are unknown and cannot be ascertained by diligent inquiry, service may, by leave of court, be effected upon him by publication in a newspaper of general circulation and in such places and for such times as the court may order. (emphasis supplied)

Since petitioner could not be personally served with summons despite diligent efforts to locate his whereabouts, respondent sought and was granted leave of court to effect service of summons upon him by publication in a newspaper of general circulation. Thus, petitioner was properly served with summons by publication.

Petitioner invokes the distinction between an action in rem and an action in personam and claims that substituted service may be availed of only in an action in rem. Petitioner is wrong. The in rem/in personam distinction was significant under the old rule because it was silent as to the kind of action to which the rule was applicable. Because of this silence, the Court limited the application of the old rule to in rem actions only.

This has been changed. The present rule expressly states that it applies [i]n any action where the defendant is designated as an unknown owner, or the like, or whenever his whereabouts are unknown and cannot be ascertained by diligent inquiry. Thus, it now applies to any action, whether in personam, in rem or quasi in rem. (Santos vs. PNOC, G.R. No. 170943, September 23, 2008)