Immunity from prosecution is a legal protection granted to a person that shields them from criminal prosecution for a particular offense or set of offenses. This protection is typically granted by a prosecutor or a court and prevents the government from using any testimony or evidence obtained from the person who was granted immunity against them in a criminal prosecution.
The Fifth Amendment of the United States Constitution provides the right against self-incrimination, which means a person cannot be compelled to testify against themselves in a criminal case. However, if a person has relevant information that is important to a case, the government may offer them immunity from prosecution to obtain their testimony. The landmark case of Kastigar v. United States, 406 U.S. 441 (1972), established the principle that immunity agreements must provide “coextensive” protection to the witness to prevent any derivative use of their testimony against them.
It is important to note that immunity from prosecution can be granted in two forms: use and derivative use immunity. Use immunity protects the witness from the use of their own testimony against them, but does not prevent the government from using other evidence obtained from independent sources. Derivative use immunity, on the other hand, provides broader protection by preventing the government from using any evidence or information derived from the witness’s testimony against them.
It is also important to note that federal grants of immunity from prosecution do not bind the state. Therefore, if a person is granted immunity from federal prosecution, they may still be prosecuted for the same offense under state law.