What Is a Prosecution Witness?

The prosecution often depends on a key witness to help make its case.
Article Details
  • Written By: Renee Booker
  • Edited By: E. E. Hubbard
  • Last Modified Date: 21 April 2014
  • Copyright Protected:
    Conjecture Corporation
  • Print this Article
Free Widgets for your Site/Blog
A 2003 blackout affected 50 million people in North America and had an economic impact of about $10 billion USD.  more...

April 23 ,  :  William Shakespeare was born and died. (1564, 1616)  more...

In a criminal prosecution, the state or federal government will often depend on a prosecution witness to prove its case. A prosecution witness is often a law enforcement officer, but may be a civilian as well. Civilian witnesses may include a victim of the crime, an expert witness, a confidential informant, or a bystander who witnessed the crime when it happened.

During a criminal trial, the prosecution must present its case to the judge or jury and convince them that the defendant committed the crime. Evidence may be admitted as part of the prosecution's case. Evidence may be in the form of documents, tangible evidence, or testimony from witnesses.

A law enforcement officer is almost always included as a prosecution witness. The law enforcement officer may testify to what information was gathered during the investigation of the crime or what was personally observed by the officer. In addition, testimony may be offered regarding any statements the defendant made to the officer after the arrest was made.

Confidential informants are also considered a prosecution witness. In many cases involving drug trafficking, a confidential informant is used to provide information or even to make purchases on the part of law enforcement from suspected traffickers. If the case goes to trial, then the confidential informant will need to testify against the defendant.


The victim of a crime, as well as bystanders, often make excellent prosecution witnesses. As a rule, their testimony is considered very credible and may be the most detailed evidence available. A victim often testifies at a sentencing hearing as well in order to express how the crime has affected him or her from an emotional standpoint.

Criminal trials frequently use scientific evidence in order to convict a defendant. DNA results, blood splatter results, ballistics, and fingerprint analysis are just a few of the possible types of scientific evidence admitted in criminal trials. In order for a jury to understand the process of analyzing and reaching conclusions based on scientific evidence, the prosecution may take testimony from an expert witness. This type of prosecution witness is responsible for explaining the results of highly scientific tests in a manner that allows the jury to understand the implications of the results.

Although a person may be listed as a witness for the prosecution, the defendant will also be given the opportunity to question the witness. The defendant may be able to establish that the witness is biased or that the testimony he or she gave was inconsistent. In some cases, a prosecution witness actually ends up being more beneficial to the defense.


Discuss this Article

Post 2

@Terrificli -- having scientific evidence is one thing. Convincing a jury it is credible is quite another. A scientist who doesn't come off well to a jury may, in fact, help a defendant's case. This is particularly true in instances when a witness is relaying highly complex testimony that isn't explained well to a jury.

In other words, explaining what evidence means is as important as having good evidence to present. To that end, scientists must take pains to make sure they can address typical folks and explain complex concepts in terms that jurors can grasp.

Post 1

Scientists and other professionals are increasingly important in criminal cases. Take the relatively new field of DNA analysis. A scientist who can, through DNA analysis, put a defendant at the scene of the crime can be particularly damaging to a criminal defendant's case. That is particularly true in the case of rape cases.

Once a scientist wielding DNA evidence convinces a jury of a defendant's guilt, the prosecution generally wins.

The importance of these witnesses cannot be understated because such scientific testimony was simply not available until recently. Advances such as fingerprint analysis and DNA evidence have gone a long way toward making sure justice is done.

Post your comments

Post Anonymously


forgot password?