Visiting Privileges at Penal Institutions
Many states allow ministers to enter correctional institutions for purposes of religious counseling and instruction. However, much discretion is given to prison authorities in deciding the conditions under which such visits will be allowed. It is customary to allow a prisoner to visit with a minister prior to the infliction of the death penalty, and some states provide for the presence of clergy at executions.
The First Amendment does not forbid outsiders from entering prisons in order to conduct religious services and to "witness" to prisoners, at least if prisoners are not forced to participate.  Campbell v. Cauthron, 623 F.2d 503 (8th Cir. 1980). The practice of many prisons in employing chaplains has also been upheld against the claim that it constitutes a violation of the First Amendment's "nonestablishment of religion" clause.  Theriault v. Silber, 547 F.2d 1279 (5th Cir. 1977), cert. denied, 434 U.S. 871 (1977).
Example. A federal appeals court ruled that a prosecutor violated the legal rights of a priest by secretly tape recording a penitential conversation between the priest and an inmate at a county jail. Mockaitis v. Harcleroad, 104 F.3d 1522 (9th Cir. 1997). A Catholic priest occasionally administered the sacrament of penance to inmates of a local county jail. On one occasion, he met with an inmate who was a suspect in the murder of three young persons. Unknown to the priest, his conversation with the inmate was being secretly recorded by the prosecuting attorney's office. The priest and archbishop brought a lawsuit in federal court claiming that the secret recording (and retention of the tape) violated the First Amendment guaranty of religious freedom, the fourth amendment protection against unreasonable searches and seizures, the Religious Freedom Restoration Act (RFRA), and the federal Wiretapping Act. The court ruled that the prosecutor's act of secretly taping a confidential communication between the inmate and priest violated the federal Religious Freedom Restoration Act and the fourth amendment prohibition against unreasonable searches and seizures. The court observed, "[T]he history of the nation has shown a uniform respect for the character of sacramental confession as inviolable by government agents interested in securing evidence of crime from the lips of criminal. … All fifty states have enacted statutes granting some form of testimonial privilege to clergy communicant communications. Neither scholars nor courts question the legitimacy of the privilege, and attorneys rarely litigate the issue. It would be strange if a privilege so generally recognized could be readily subverted by the governmental recording of the privileged communication and the introduction of the recording into evidence."