Which legal principle safeguards certain information from disclosure in fraud investigations?

The legal principle that safeguards certain information from disclosure in fraud investigations is attorney-client privilege. This principle serves to encourage open and honest communication between clients and their attorneys. By ensuring that communications made in confidence cannot be disclosed without the client's consent, attorney-client privilege promotes thorough legal advice and representation without fear of exposure.

In the context of fraud investigations, this privilege is particularly important, as it allows individuals to seek legal counsel without the risk that their disclosures during that process could later be used against them. It ensures that sensitive information, strategies, and discussions aimed at formulating a defense or understanding legal implications remain protected.

The other options do not specifically serve to protect client communications in the same way. Double jeopardy pertains to the legal prohibition of being tried twice for the same offense, which does not affect disclosure of information. Hearsay rules relate to the admissibility of evidence in court and are not designed to protect communications. The exclusionary rule prevents the use of illegally obtained evidence in court, focusing on the manner of obtaining evidence rather than protecting communications between a client and attorney. Thus, attorney-client privilege is the correct answer, as it directly addresses the protection of confidential conversations in legal matters.