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A DNA Evidence Primer

NCJ Number
Date Published
1 page

This article summarizes "What Every law Enforcement Officer Should Know About DNA Evidence," a brochure produced by the National institute of Justice and the National Commission on the Future of DNA Evidence, so as to explain DNA and the related identification, preservation, and collection issues that every law enforcement officer should know.


DNA (deoxyribonucleic acid) is the fundamental building block for an individual's entire genetic makeup and is a component of virtually every cell in the human body. Each person's DNA is different from every other individual's, except for identical twins. DNA collected from a crime scene can thus link a suspect to or exclude a suspect from a crime scene. As with fingerprints, when DNA collected from the crime scene is compared with a "known" print or sample, the person from whom the sample is taken can either be placed at or excluded from the crime scene. Every officer, from the first responding patrol officer to the experienced detective and the crime scene specialist, should be aware of important issues involved in the identification, collection, transportation, and storage of DNA evidence. Issues and procedures in these areas are identified and outlined. One investigative tool available to law enforcement personnel is CODIS (Combined DNA Index System), which is an electronic database of DNA profiles that can identify suspects. All 50 States are in the process of implementing a DNA index of individuals convicted of certain crimes, such as rape, murder, and child abuse.

Date Published: January 1, 2000