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What Every Law Enforcement Officer Should Know About DNA Evidence

Investigators and Evidence Technicians

Database Files

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National Institute of Justice (NIJ) (see reuse policy).

The CODIS uses two database files to generate investigative leads in crimes where biological evidence is recovered from the crime scene.

The Offender file contains DNA profiles of individuals arrested or convicted of certain crimes; when a crime scene profile matches an offender profile, it is called an offender hit.

The Forensic file contains DNA profiles developed from crime scene evidence, such as semen or blood stains; when two or more crime scene profiles match, it is called a forensic hit.

The CODIS utilizes computer software to automatically search these files for matching DNA profiles (just as fingerprints can be searched through AFIS).

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