What type of immunity is granted to grand jury witnesses, and what does it protect?

• A. Use immunity; protects from use of compelled testimony
• B. Transactional immunity; protects from prosecution for offenses involved
• C. Derivative immunity; protects from use of evidence derived from testimony
• D. No immunity; testimony can be used in prosecution

Answer: (B)

Transactional immunity is the protection granted to grand jury witnesses. It bars the government from prosecuting the witness for any offenses related to the testimony they give. The idea is to let the witness be fully truthful without fearing prosecution for the crimes they discuss, since the prohibition covers prosecutions for those offenses even if evidence arises from the testimony itself.

This is broader than use immunity, which only prevents the government from using the compelled testimony (and evidence derived from it) against the witness in prosecution. Derivative-use immunity protects against using evidence derived from the testimony but does not conclusively shield the witness from prosecution for the offenses involved. No immunity would leave the witness open to prosecution based on the testimony.