P.R. Laws Ap. tit. 32A, § III, Rule 30.1
Any party may serve upon any other party written interrogatories to be answered by the party so served or, if the party served is a public or private corporation or a partnership or association or governmental agency, by any officer, official or agent, who shall furnish such information as is available to the party. Interrogatories may, without leave of court, be served upon the plaintiff after commencement of the action. They may also be served upon any other party to the action, provided said party has been duly summoned and they are attached to the summons served on said party. Each interrogatory shall be answered separately and fully in writing under oath, unless it is objected to.
If the interrogatory were objected to, the reasons for objection shall be stated by motion in lieu of an answer and a copy of the interrogatory objected to shall be furnished. If only part of the interrogatory were objected to, the party objecting to it shall include the question verbatim, together with a statement of the reasons for objection. If this be the case, the objecting party shall serve, together with his objections, the answers to the remainder of the interrogatory upon the party who submitted it.
The answers are to be signed and sworn by the person making them. The party upon whom the interrogatories have been served shall serve a copy of the answers or objections if any, or both, upon the party who served the interrogatories within thirty (30) days after service thereof. The court may, upon motion and good cause shown, allow a shorter or longer time.
The party submitting the interrogatories may make objections to the answers thereto by motion to that effect which shall include a verbatim transcript of the question and answer involved and the reasons for objection.
The party submitting the interrogatories may move for an order under Rule 34 with respect to any objection to or other failure to answer an interrogatory.