Which rule of evidence prevents the admission of improperly obtained evidence?

The exclusionary rule is a legal principle that prohibits the admission of evidence obtained in violation of a person's constitutional rights, particularly under the Fourth Amendment, which guards against unreasonable searches and seizures. This rule is vital in maintaining the integrity of the judicial process by ensuring that law enforcement acts within the boundaries of the law when gathering evidence.

When evidence is obtained through illegal means, such as without a warrant, lacking probable cause, or in violation of an individual's right to privacy, it cannot be used against the individual in court. This safeguard not only protects the rights of individuals but also serves to deter law enforcement from conducting unlawful searches.

While the other rules listed, such as the admissibility rule, hearsay rule, and chain of custody rule, have significant roles in the context of evidence in legal proceedings, they do not specifically address the legality of how evidence is obtained. The admissibility rule relates generally to whether certain types of evidence can be presented in court. The hearsay rule pertains to the use of out-of-court statements to prove the truth of the matter asserted, while the chain of custody rule ensures the integrity and proper handling of evidence after it has been collected. Thus, the exclusionary rule is the key principle that directly relates to the