Which case is known for issues related to impeachment in law enforcement?

Giglio vs. United States is widely recognized for its implications regarding the disclosure of information that can affect the credibility of law enforcement witnesses in legal proceedings. The case established that the prosecution must disclose evidence that is favorable to the accused and that could be used to impeach the credibility of government witnesses. This principle is crucial in ensuring a fair trial, as it obligates law enforcement and prosecutors to provide information that might undermine the reliability of their own testimony.

The Giglio ruling emphasizes the importance of transparency in law enforcement, specifically when officers may have a history or trait that could affect their credibility as witnesses. This duty includes not only revealing evidence of misconduct or bias but also involves ensuring that all relevant details may be examined by defense attorneys to properly challenge the integrity of witness testimonies.

In contrast, the other cases listed relate to different aspects of the law and do not focus on issues of witness impeachment: Mapp vs. Ohio deals primarily with the exclusionary rule and illegal searches, Ferguson vs. City of Charleston addresses issues about privacy and the rights of individuals in law enforcement situations, and Riley vs. California centers on search and seizure laws regarding cell phones. These distinctions highlight why Giglio vs. United States is specifically associated with issues of impeachment in law enforcement