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Principles of Forensic DNA for Officers of the Court

What Is a Reference Sample and How Is It Used?

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Photo of female inmate taking a DNA swab in the mouth
National Institute of Justice (NIJ) (see reuse policy).

Biological known reference samples such as blood or saliva can be collected from the victim, suspect, a consensual sex partner(s), relatives or any other person who might have had access to the crime scene during the course of a criminal investigation or trial. These samples can be used to identify and/or exclude the source of the DNA profile(s) contained in the evidence sample.

It is imperative that reference samples are collected as soon as possible to allow for the forensic analysis to progress.

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