Uses of DNA Evidence

DNA Evidence in Unsolved and Postconviction Cases

Advanced DNA technology, such as PCR, makes it possible to obtain conclusive results in cases in which previous testing might have been inconclusive. This can result in the identification of suspects in previously unsolvable cases or the exoneration of those wrongfully convicted. It is important to realize that while testing or retesting may exonerate an individual, exclusionary results may not necessarily prove actual innocence. Prosecutors, defense counsel, the court, and law enforcement should confer on the need for testing on a case-by-case basis. 

See also "The Role of the Victim's Advocate" from Postconviction DNA Testing: Recommendations for Handling Requests, September 1999, National Institute of Justice.

Using CODIS To Solve Crime

CODIS uses two indexes to generate investigative leads in crimes that contain biological evidence. The forensic index contains DNA profiles from biological evidence left at crime scenes, and the offender index contains DNA profiles of individuals convicted of violent crime. Each State in the Nation has a DNA database law that defines which convicted offenders must have their profiles entered into CODIS; some States even require that DNA profiles from all felons be entered into the database. CODIS enables Federal, State, and local forensic crime laboratories to work together—between jurisdictions and across State lines—to solve crimes.

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From Understanding DNA Evidence: A Guide for Victim Serice Providers, May 2001, Brochure, National Institute of Justice and Office for Victims of Crime