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.
Exculpatory Evidence Definition
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 is what one can define as exculpatory evidence.

According to U.S. law, there are two different types of legal cases: civil cases and criminal cases. But how is a civil case different...
What follows is a comprehensive guide on what is exculpatory evidence and why it is important in criminal cases, as well as remedies and consequences of failure to disclose exculpatory evidence. The guide also presents exculpatory evidence examples and exculpatory evidence 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 exculpatory evidence 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 constitutional rights of the accused, have a legal duty to share exculpatory evidence with the defense. It is a miscarriage of justice should they fail to do so.
Prosecution Versus 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?
Inconsistent statements of witnesses
In the case of Kyles v. Whitley [514 U.S. 419, (1995)], 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 evidence to the defense. This included inconsistent statements made by Beanie and other eyewitnesses, as well as Beanie’s self-incriminatory statements. 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. It also held that the non-disclosure is material when the results of the proceedings would have differed had the prosecution disclosed the information.
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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 on 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 prosecution, however, did not disclose Boblit’s written confession that he alone killed the 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
Perry Mason is a television show that aired from 1957 to 1966, where defense attorney Perry Mason often proved the innocence of his clients, who seemed guilty in the beginning. This is believed to have caused misconceptions about criminal trial proceedings. The show is said to have created the expectation that the defendant has the burden to prove their innocence, rather than the prosecution having to prove guilt beyond a reasonable doubt. Such public perceptions, especially among jurors who are not very familiar with legal terms or principles, make exculpatory evidence, if it exists, even more valuable to secure an acquittal.
Frequently Asked Questions
When must Brady and/or Giglio material be disclosed?
Regardless of whether the defendant requests it or not, prosecutors have the legal obligation to disclose exculpatory evidence.
Does the Brady Rule apply in civil cases?
No. In civil cases, the liberty of the defendant is not at stake. Also, unlike criminal procedure, the civil procedure allows for more avenues to discover evidence. However, the rule may be applied in administrative cases, according to a White House directive in 2020.
How is a Brady violation determined?
The test on whether a Brady violation was committed is called the “reasonable probability of a different result standard.” Here, the court will have to ask: Will this evidence yield a different result (i.e., the acquittal of the accused or dismissal of the case) if this were admitted and presented? If the answer is yes, then such evidence is considered Brady material, and the failure to disclose or share it with the defendant would be a deprivation of a fair trial and, thus, is considered a Brady violation.