What Does the Term "Exculpatory Evidence" Mean?

Updated January 15, 2024
11 min read
What Does the Term "Exculpatory Evidence" Mean?


In criminal law, it is a long-held principle that every person accused of a crime is presumed innocent until proven guilty. That is why the prosecution has the burden to prove guilt beyond a reasonable doubt to secure a conviction. Evidence that is presented to prove this is called inculpatory evidence.

In complementary contrast to inculpatory evidence, there exists "exculpatory evidence." But what does exculpatory evidence mean? 

What Is Exculpatory Evidence?

The definition of exculpatory evidence is vital in understanding its role in a criminal trial. The defendant in a criminal case does not actually have to prove their innocence, which is already presumed. However, they may present favorable evidence to either cast doubt on their guilt or exonerate them from the crime. Such evidence explanation can define exculpatory evidence. Legal professionals often work rigorously to unearth such evidence that can significantly influence legal proceedings' outcomes.

What follows is a comprehensive guide on exculpatory evidence meaning and why it is important in criminal cases, as well as remedies and consequences of failure to disclose exculpatory evidence. This Lawrina guide also presents examples of exculpatory evidence and exculpatory evidence in civil cases or criminal cases.

Why Is Exculpatory Evidence Important?

The principles of the American justice system, which has roots in British Common Law, have long favored protecting the innocent more than punishing the guilty. The English jurist William Blackstone once wrote, “Better that ten guilty persons escape than that one innocent suffer.”

This is why the exculpatory evidence rule is important because it will prevent the imprisonment of an innocent or probably innocent person. The defendant’s right to liberty is at stake. This is also why prosecutors, in the interest of justice, fair play, and the protection of the accused's constitutional rights, have a legal duty to share exculpatory evidence with the defense. It is a miscarriage of justice should they fail to do so.

Exculpatory evidence refers to any information that can prove a person’s innocence or absolve them from liability. Some examples include alibi witnesses, conflicting eyewitness testimonies, and physical evidence contradicting the prosecution's case. A character reference letter for court can also serve as exculpatory evidence, as it can provide testimony to the defendant's moral character and potentially cast doubt on their likelihood of committing the alleged crime.

Does a prosecutor have to disclose exculpatory evidence?

It's a fundamental requirement under exculpatory evidence definition law that a prosecutor has to disclose such evidence. Concealing exculpatory evidence can result in a violation of due process, leading to a reversal of convictions and penalties for the prosecution. This ruling underscores the central principle of fairness in the legal system.

Prosecution vs. Defense in a Trial

Because of the doctrine of presumption of innocence, it is the prosecution that must prove the defendant’s guilt beyond a reasonable doubt. The prosecution has to search for evidence that will convince the jury the defendant is guilty and present these pieces of evidence in court. This can come in the form of testimony, objects, science (forensics), or documents.

The defense team does not have the parallel burden to prove their innocence. In fact, the defendant may even opt not to testify in light of the doctrine against self-incrimination (Fifth Amendment to the Constitution). It is enough that the defense can cast doubt on the prosecution’s accusations and claims. If there is exculpatory evidence that totally exonerates the defendant, then it can increase the chances of an acquittal. 

However, during the investigation, the prosecution may encounter evidence that does not help their case. As officers of the court, they must turn over exculpatory evidence to the defense or risk a mistrial.

What Are Examples of Exculpatory Evidence?

In any legal dispute, evidence plays a critical role in determining the outcome of the case. Among various types of evidence that can arise during a trial, one indispensable type is exculpatory evidence.

Exculpatory evidence refers to any information that can prove a person’s innocence or absolve them from liability. It is critically important in criminal trials, where such evidence can discredit the prosecution's case, but it also plays a significant role in civil cases. Here are some examples of exculpatory evidence.

Inconsistent statements of witnesses

In the case of Kyles v. Whitley [514 U.S. 419, (1995)], an example of exculpatory evidence, the jury convicted Curtis Kyles of murdering an elderly woman after James Joseph, also known as Beanie (among many aliases) and a police informant, reported purchasing the woman’s car from Kyles on the day of the murder. 

The Supreme Court granted a new trial, taking into account the fact that the police did not disclose exculpatory statements to the defense. The Court took into account the possibility of an acquittal had the prosecution shared such evidence with the defense. This is called the “reasonable probability of a different result standard,” which was discussed in the case of United States v. Bagley [473 U.S. 667, 105 S. Ct. 3375 (1985)].

Tampering with witnesses

In the case of United States v. Bagley, which was also cited in Kyles v. Whitley, the prosecution did not disclose that the prosecution’s witnesses received payment to testify and provide information. The defense argued that this impaired the right of the defendant to effectively confront those who testified against him. The Supreme Court remanded the case for further proceedings.

Brady Material or the Brady Rule

The landmark case of Brady v. Maryland [373 U.S. 83, 83 S. Ct. 1194 (1963)] set in stone the doctrine of exculpatory evidence, also known as the Brady Rule. In this case, the jury convicted two men, John Leo Brady and Charles Donald Boblit, and sentenced them to death for the murder of an acquaintance. Although Brady admitted to his involvement, he claimed that only Boblit actually killed the murder victim. 

The Supreme Court held that “where the evidence is material either to guilt or to punishment,” withholding such exculpatory evidence on the demand of the accused violates the due process clause of the Fourteenth Amendment to the United States Constitution. 

What happens if there is a Brady violation?

When a prosecutor fails to fulfill a legal obligation to turn over exculpatory evidence to the defense, then there is a Brady violation. The consequences of such a violation and the available remedies differ depending on when the prosecution learns of it. The prosecutor may also be held liable for penalties.

  • Before trial: The defense may move to challenge the evidence or charges, or the court may dismiss the case with prejudice (meaning the defendant can’t be tried) or without prejudice (meaning the defendant can be tried). 

  • During trial: The defense may move to acquit the defendant so the judge can bypass a jury verdict. The defense may also move for a new trial or a mistrial.

  • After conviction: The defense may file an appeal or a motion for a new trial. 

What Is a Giglio Violation?

The Supreme Court expanded the Brady doctrine in the case of Giglio v. United States, [405 U.S. 150 (1972)]. In Brady, the defense must demand that the prosecution disclose exculpatory evidence. Under the new doctrine in Giglio, however, all evidence that may impeach the credibility of prosecution witnesses has to be disclosed, with or without a demand.

The Perry Mason Effect

The popular television show Perry Mason (1957-1966) featured Perry Mason, a defense attorney, frequently vindicating seemingly guilty clients. This portrayal may have misled the public into thinking the defense must prove innocence rather than the prosecution proving guilt beyond a reasonable doubt. These misconceptions increase the value of exculpatory evidence in winning acquittals, especially amongst jurors unfamiliar with legal concepts.

Article by
Yevheniia Savchenko

Yevheniia Savchenko is a Product Content Manager at Lawrina. Yevheniia creates user interface copies for Lawrina products, writes release notes, and helps customers get the best user experience from all Lawrina products. Also, Yevheniia is in charge of creating helpful content on legal template pages (Lawrina Templates) and up-to-date information on US law (Lawrina Guides). In her spare time, Yevheniia takes up swimming, travels, and goes for a walk in her home city.

If you have any questions or suggestions regarding the product or UX content for Lawrina, feel free to contact Yevheniia directly at y.savchenko@lawrina.org or connect with her on LinkedIn.