P.R. Laws tit. 34, § 1473
If a person comes to Puerto Rico in obedience to a summons directing him to attend and testify in a criminal prosecution in this Commonwealth, he shall not, while in this Commonwealth pursuant to such summons, be subject to arrest or to the service of process, civil or criminal, in connection with matters which arose before his entrance into this commonwealth under the summons.
If a person passes through this Commonwealth while going to another state or territory in obedience to a summons to attend and testify in that state or territory, or while returning therefrom, he shall not, while so passing through this Commonwealth, be subject to arrest or to the service of process, civil or criminal, in connection with matters which arose before his entrance into this Commonwealth under the summons.
History —May 13, 1934, No. 60, p. 416, § 3, eff. 90 days after May 13, 1934.