Which immunity prevents prosecutors from using a witness's compelled testimony, or evidence derived from it, in a prosecution?

Which immunity prevents prosecutors from using a witness's compelled testimony, or evidence derived from it, in a prosecution?

• A. Use Immunity
• B. Transactional Immunity
• C. Absolute Immunity
• D. Qualified Immunity

Answer: (A)

The key idea here is understanding how different types of immunity protect a witness from criminal prosecution based on compelled testimony. Use immunity is designed to keep the testimony from being used against the witness in a prosecution, and it also blocks evidence derived directly from that testimony from being used against the witness. In practice, the witness can’t be prosecuted for offenses related to what they testified about, as long the case relies on the compelled testimony or its fruits. But if prosecutors have independent, non-derived evidence, they can still pursue charges based on that separate evidence. Transactional immunity, by contrast, would shield the witness from prosecution for offenses related to the compelled testimony itself, regardless of what evidence the prosecution has beyond that testimony. Absolute immunity and qualified immunity aren’t aimed at preventing use of compelled testimony in criminal prosecutions; they relate to official duties or civil liability for government actors, not to the procedural protection of a witness’s testimony in court.

The key idea here is understanding how different types of immunity protect a witness from criminal prosecution based on compelled testimony. Use immunity is designed to keep the testimony from being used against the witness in a prosecution, and it also blocks evidence derived directly from that testimony from being used against the witness. In practice, the witness can’t be prosecuted for offenses related to what they testified about, as long the case relies on the compelled testimony or its fruits. But if prosecutors have independent, non-derived evidence, they can still pursue charges based on that separate evidence.

Transactional immunity, by contrast, would shield the witness from prosecution for offenses related to the compelled testimony itself, regardless of what evidence the prosecution has beyond that testimony. Absolute immunity and qualified immunity aren’t aimed at preventing use of compelled testimony in criminal prosecutions; they relate to official duties or civil liability for government actors, not to the procedural protection of a witness’s testimony in court.