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Principles of Forensic DNA for Officers of the Court


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illustration of horizontal DNA double helix with the text "COLD HIT" in the foreground
National Institute of Justice (NIJ) (see reuse policy).

When CODIS software recognizes the same DNA profile in the Forensic or Offender Index, it identifies the two profiles as a match. These matches are commonly referred to as "hits."

After CODIS software produces a hit, qualified laboratory personnel analyze the DNA samples to either validate or refute the match. This is usually done as a precautionary measure to make sure there are no problems with data entry. There are times, however, when the DNA profile found on crime scene evidence is a mixture of more than one person's DNA. In that case, analysts must compare profiles to see if the individual's profile is part of the mixed DNA.

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