Pennsylvania Statutes Title 42 Pa.C.S.A. Judiciary and Judicial Procedure § 5965. Exemption from arrest and service of process

(a) Incoming witnesses.--If a person comes into this Commonwealth in obedience to a summons directing him to attend and testify in this Commonwealth he shall not while in this Commonwealth pursuant to such summons be subject to arrest or the service of process, civil or criminal, in connection with matters which arose before his entrance into this Commonwealth under the summons.

(b) Witnesses in transit.--If a person passes through this Commonwealth while going to another state in obedience to a summons to attend and testify in that state, or while returning therefrom, he shall not while so passing through this Commonwealth be subject to arrest or the service of process, civil or criminal, in connection with matters which arose before his entrance into this Commonwealth under the summons.