California, United States of America
The following excerpt is from Falls v. Superior Court, 42 Cal.App.4th 1031, 49 Cal.Rptr.2d 908 (Cal. App. 1996):
The actions of petitioners consist of subpoenaing a witness for a judicial hearing and interviewing that witness prior to the hearing. Such actions are indivisible from and "intimately associated with" the act of initiating a criminal prosecution--for which a prosecutor has always enjoyed immunity. (Imbler v. Pachtman, supra, 424 U.S. 409, 421-422, 96 S.Ct. 984, 990-991.)
Prosecutions cannot proceed without witnesses and unless subpoenaed there would be no witnesses.
The above passage should not be considered legal advice. Reliable answers to complex legal questions require comprehensive research memos. To learn more visit www.alexi.com.