CODIS photo


CODIS, or the Combined DNA Index Systems, is a computer program that contains local, state, and national databases of DNA profiles collected from convicted offenders, DNA profiles from crime scene evidence, and DNA profiles of missing persons.

Having this program allows state, local, and national law enforcement crime labs to compare DNA profiles from a specific crime to the entire database of DNA profiles.

How Does CODIS Work?

CODIS uses two indexes to organize information in their database:

  1. The "Convicted Offender Index" contains DNA profiles of individuals convicted of certain crimes. In Massachusetts, the DNA profile of every adult convicted of a felony is added to the database. Each state sets its own laws governing who is entered into the database.
  2. The "Forensic Index" contains DNA profiles from crime scene evidence.

CODIS searches across both of these indexes for a match. A match made between the Forensic Index and the Convicted Offender Index can provide law enforcement with the identity of a suspect(s).

Limitations of CODIS

  • A match in CODIS does not, by itself, prove that a sexual assault occurred. A match would only indicate that the offender was there. Sometimes offenders use the "consent defense," saying that the survivor actually said yes, or consented, to sex.
  • Not all DNA profiles from crime scenes are in the "Forensic Index." After CODIS was established in 2000, crime labs only entered DNA profiles from previously collected sexual assault evidence collection kits that met the following criteria:
    1. Cases that were unsolved.
    2. Cases that were still within the statute of limitations, which for adults is 15 years.
  • If the perpetrator has not been involved in the legal system, or another crime, their DNA profile will not be in either Index.

If you were assaulted before 2000, had a sexual assault exam and evidence collection kit performed and reported the assault to the police, you may want to check on the status of your case in CODIS. Call the Forensics Information line at 866-463-3799.

Forensics for Survivors © 2015 All Rights Reserved

This project was supported by Grant #2009-WF-AX-0014 awarded by the Violence Against Women Grants Office, Office of Justice Programs, U.S. Department of Justice to the Massachusetts Executive Office of Public Safety & Security Office of Grants & Research and subgranted to the Boston Area Rape Crisis Center. Points of view in this document are those of the author(s) and do not necessarily represent the official position or policies of the U.S. Department of Justice or the Massachusetts Executive Office of Public Safety Programs Division.