DNA | Definition

Doc's CJ Glossary by Adam J. McKee
Course: Criminal Investigations

DNA, or deoxyribonucleic acid, is a unique genetic material present in every cell of the body and is used as evidence in criminal investigations.

Forensic science often plays a crucial role in criminal justice. At the heart of it, we find DNA, which acts like a fingerprint at the microscopic level. That’s because it is a unique identifier. No two people, except for identical twins, have the same DNA. This uniqueness makes it a perfect tool for solving crimes.


DNA evidence isn’t found just in people. It’s present in every living organism. This means a criminal might leave behind this valuable evidence at a crime scene without realizing it. For example, they might shed skin cells, leave behind hair, or even drop saliva. Forensic scientists gather these tiny clues carefully. They use specialized equipment and follow strict procedures to prevent contaminating the evidence.

DNA Analysis

Once scientists have collected evidence, they take it to a laboratory. Here, they use advanced techniques to analyze it. The process starts with extracting DNA from the samples. They then create a profile, which is like a genetic fingerprint.

Forensic scientists compare this profile with the profiles of suspects. They also compare it to databases containing profiles of known criminals. If there’s a match, they have strong evidence linking a person to the crime scene.

Violent Crime Cases

This evidence is especially useful in violent crime cases. In situations involving murder or sexual assault, the criminal often leaves behind DNA. This evidence can help link a suspect to the crime scene. It can also identify the victim if their identity is unknown.

Property Crime Cases

But it isn’t just useful in violent crimes. It also plays a role in solving property crimes like burglaries and thefts. For instance, a burglar might cut themselves, break a window, and leave behind blood, a source of DNA. Or, they might leave behind sweat on a stolen object. By collecting and analyzing this evidence, investigators can track down the criminal.

DNA Exonerates Innocent Individuals

Not only does DNA help to convict the guilty, but it also helps to prove the innocence of those wrongly accused. If DNA collected at a crime scene doesn’t match the DNA of a suspect, this evidence can be used to exclude them from suspicion. This ability to clear the innocent is another reason why DNA evidence is so valuable in the criminal justice system.

In conclusion, DNA is a powerful tool in criminal justice. Its uniqueness makes it an excellent means of identifying individuals. By collecting and analyzing DNA, forensic scientists provide crucial evidence that can help convict the guilty, exonerate the innocent, and bring justice to victims.

[ Glossary ]

Last Modified: 05/16/2023

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