Rule 21, Sec. 2Rule 21, Sec. 2

By whom issued. The subpoena may be issued by

(a) the court before whom the witness is required to attend;

(b) the court of the place where the deposition is to be taken;

(c) the officer or body authorized by law to do so in connection with investigations conducted by said officer or body; or

(d) any Justice of the Supreme Court or of the Court of Appeals in any case or investigation pending within the Philippines.

When application for a subpoena to a prisoner is made, the judge or officer shall examine and study carefully such application to determine whether the same is made for a valid purpose.

No prisoner sentenced to death, reclusion perpetua or life imprisonment and who is confined in any penal institution shall be brought outside the said penal institution for appearance or attendance in any court unless authorized by the Supreme Court (2a, R23)