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National DNA Index System (NDIS)

The National DNA Index System (NDIS) is a vital computerized resource established in 1998, operated by the Federal Bureau of Investigation (FBI) as part of the Combined DNA Index System (CODIS). It serves as a national repository for DNA profiles, facilitating collaboration among state and local law enforcement agencies to identify missing persons and solve crimes. NDIS supports criminal investigations by allowing agencies to electronically search for matches between DNA samples collected from crime scenes and profiles of known offenders. This system plays a crucial role in enhancing public safety by enabling the identification of serial offenders and helping to exonerate the wrongfully convicted.

NDIS contains five categories of DNA profiles, including those from convicted offenders, crime scenes, unidentified remains, relatives of missing persons, and reference samples from missing individuals. Importantly, it maintains strict privacy protocols, ensuring that personal identifying information is not included in the database. Each profile is linked only to non-identifying information, accessible only to authorized personnel. Participation in NDIS varies by state, influenced by local laws regarding DNA sample collection. As forensic technology advances, there are ongoing discussions about expanding NDIS to include newer methods and databases to further enhance its capabilities in crime-solving and identification efforts.

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  • DATE: Established in 1998
  • IDENTIFICATION: Computerized system for storing DNA profiles, maintained and operated by the Federal Bureau of Investigation and supported by the Combined DNA Index System, that permits state and local law enforcement agencies to collaborate in identifying missing persons and matching DNA profiles of suspected offenders to unsolved crimes.

SIGNIFICANCE: Technological advances in DNA analysis and computerized comparison of DNA profiles have created a powerful crime-solving tool at the national level. The National DNA Index System enables law enforcement agencies to identify violent criminal offenders and match them to unsolved crimes across state lines, and it also possesses the power to exonerate the wrongfully convicted. The National DNA Index System allows law enforcement agencies across the United States to communicate about and collaborate in criminal investigations at a level never before possible.

The National DNA Index System (NDIS) is an electronic resource of DNA profiles designed to aid in criminal investigations as well as searches for missing persons at the national level. Established in response to the Violent Crime Control and Law Enforcement Act of 1994 and operated by the Federal Bureau of Investigation (FBI), NDIS became operational in 1998. This system represents the highest level in the Combined DNA Index System (CODIS) hierarchy. CODIS, which began as a pilot project in 1990, represents a database of DNA profiles collected by law enforcement agencies across the United States. CODIS is a computerized DNA profile processing system that provides law enforcement agencies with the ability to search electronically for DNA profile matches. The CODIS hierarchy includes support at the national (NDIS), state (State DNA Index System, or SDIS), and local (Local DNA Index System, or LDIS) levels. DNA profiles from the state and local levels constitute NDIS.

The primary purpose of NDIS is to assist in criminal investigations across state and local levels by providing an electronic database containing DNA profiles from participating laboratories across states. NDIS offers law enforcement agencies in different states the opportunity to search for possible matches between suspected or convicted criminals and DNA profiles obtained from the scenes of unsolved crimes. This index system also enables the identification of serial offenders. By 2025, NDIS included more than nineteen million offender profiles.

The federal DNA Identification Act of 1994 requires NDIS to record the following DNA profile categories: DNA samples from individuals convicted of crimes or charged with a crime, DNA samples from persons collected under specific legal authorities as applicable, DNA samples recovered from crime scenes, DNA samples from unidentified human remains, DNA samples from relatives of missing persons, and reference samples from missing persons. Relatives of missing persons may contribute DNA samples to NDIS voluntarily; the collection and use of DNA samples from individuals convicted of qualifying offenses is governed by federal and state statutes and associated procedural safeguards. In respect to criminal investigations, DNA samples from individuals convicted of crimes and DNA samples recovered from crime scenes are separated into two primary indexes, the offender index and the forensic index. Through NDIS, law enforcement agencies can identify missing individuals, match offenders to previously unsolved crimes, and make connections between separate crime scenes.

To prevent personal identification from DNA profiles, no personal information is provided in NDIS, and only authorized personnel have access to identifying information. Each DNA profile in NDIS is connected only with the following information: identification of the particular laboratory or agency that submitted the profile, the name of the staff member associated with the DNA analysis, and an identification number for the specimen. Access to identifying information associated with DNA profiles is subject to federal policy, auditing procedures, and interagency agreements designed to limit unauthorized use.

All fifty US states contribute DNA profiles to NDIS, but the collection of DNA samples varies across states. As a result, some states submit more DNA profiles than do other states. The number of profiles submitted is not related to the level of crime in a state; rather, it is related to state laws that specify what types of offenders are required to submit DNA samples. For example, some states require submission of DNA samples in connection with only a small number of serious offenses, whereas other states permit law enforcement agencies wide latitude in collecting DNA samples from suspects and convicted offenders. Some state laws permit the collection of samples from all persons arrested, whether they are ultimately convicted.

Since the early twenty-first century, policy discussions and academic literature have examined potential expansions of forensic DNA databases, including broader qualifying offense categories and the use of techniques such as partial matching, familial searching, rapid DNA systems, next-generation sequencing, and investigative genetic genealogy. The application of these approaches within NDIS has been subject to evolving legal standards, agency policies, and oversight requirements.




Bibliography

Butler, John M. Forensic DNA Typing: Biology, Technology, and Genetics of STR Markers. 2nd ed., Elsevier Academic Press, 2005.

Lazer, David, editor. DNA and the Criminal Justice System: The Technology of Justice. MIT Press, 2004.

Lee, Henry C., and Frank Tirnady. Blood Evidence: How DNA Is Revolutionizing the Way We Solve Crimes. Perseus, 2003.

Wickenheiser, Ray A. “Expanding DNA Database Effectiveness.” Forensic Science International Synergy, 5 Apr. 2022, doi:10.1016/j.fsisyn.2022.100226. Accessed 17 Dec. 2025.

"Frequently Asked Questions on CODIS and NDIS ." Federal Bureau of Investigation, www.fbi.gov/how-we-can-help-you/dna-fingerprint-act-of-2005-expungement-policy/codis-and-ndis-fact-sheet. Accessed 23 Dec. 2025.

Federal Bureau of Investigation. “Federal DNA Identification Act.” Federal Bureau of Investigation, le.fbi.gov/science-and-lab/biometrics-and-fingerprints/codis/federal-dna-identification-act. Accessed 17 Dec. 2025.

Full Article

  • DATE: Established in 1998
  • IDENTIFICATION: Computerized system for storing DNA profiles, maintained and operated by the Federal Bureau of Investigation and supported by the Combined DNA Index System, that permits state and local law enforcement agencies to collaborate in identifying missing persons and matching DNA profiles of suspected offenders to unsolved crimes.

SIGNIFICANCE: Technological advances in DNA analysis and computerized comparison of DNA profiles have created a powerful crime-solving tool at the national level. The National DNA Index System enables law enforcement agencies to identify violent criminal offenders and match them to unsolved crimes across state lines, and it also possesses the power to exonerate the wrongfully convicted. The National DNA Index System allows law enforcement agencies across the United States to communicate about and collaborate in criminal investigations at a level never before possible.

The National DNA Index System (NDIS) is an electronic resource of DNA profiles designed to aid in criminal investigations as well as searches for missing persons at the national level. Established in response to the Violent Crime Control and Law Enforcement Act of 1994 and operated by the Federal Bureau of Investigation (FBI), NDIS became operational in 1998. This system represents the highest level in the Combined DNA Index System (CODIS) hierarchy. CODIS, which began as a pilot project in 1990, represents a database of DNA profiles collected by law enforcement agencies across the United States. CODIS is a computerized DNA profile processing system that provides law enforcement agencies with the ability to search electronically for DNA profile matches. The CODIS hierarchy includes support at the national (NDIS), state (State DNA Index System, or SDIS), and local (Local DNA Index System, or LDIS) levels. DNA profiles from the state and local levels constitute NDIS.

The primary purpose of NDIS is to assist in criminal investigations across state and local levels by providing an electronic database containing DNA profiles from participating laboratories across states. NDIS offers law enforcement agencies in different states the opportunity to search for possible matches between suspected or convicted criminals and DNA profiles obtained from the scenes of unsolved crimes. This index system also enables the identification of serial offenders. By 2025, NDIS included more than nineteen million offender profiles.

The federal DNA Identification Act of 1994 requires NDIS to record the following DNA profile categories: DNA samples from individuals convicted of crimes or charged with a crime, DNA samples from persons collected under specific legal authorities as applicable, DNA samples recovered from crime scenes, DNA samples from unidentified human remains, DNA samples from relatives of missing persons, and reference samples from missing persons. Relatives of missing persons may contribute DNA samples to NDIS voluntarily; the collection and use of DNA samples from individuals convicted of qualifying offenses is governed by federal and state statutes and associated procedural safeguards. In respect to criminal investigations, DNA samples from individuals convicted of crimes and DNA samples recovered from crime scenes are separated into two primary indexes, the offender index and the forensic index. Through NDIS, law enforcement agencies can identify missing individuals, match offenders to previously unsolved crimes, and make connections between separate crime scenes.

To prevent personal identification from DNA profiles, no personal information is provided in NDIS, and only authorized personnel have access to identifying information. Each DNA profile in NDIS is connected only with the following information: identification of the particular laboratory or agency that submitted the profile, the name of the staff member associated with the DNA analysis, and an identification number for the specimen. Access to identifying information associated with DNA profiles is subject to federal policy, auditing procedures, and interagency agreements designed to limit unauthorized use.

All fifty US states contribute DNA profiles to NDIS, but the collection of DNA samples varies across states. As a result, some states submit more DNA profiles than do other states. The number of profiles submitted is not related to the level of crime in a state; rather, it is related to state laws that specify what types of offenders are required to submit DNA samples. For example, some states require submission of DNA samples in connection with only a small number of serious offenses, whereas other states permit law enforcement agencies wide latitude in collecting DNA samples from suspects and convicted offenders. Some state laws permit the collection of samples from all persons arrested, whether they are ultimately convicted.

Since the early twenty-first century, policy discussions and academic literature have examined potential expansions of forensic DNA databases, including broader qualifying offense categories and the use of techniques such as partial matching, familial searching, rapid DNA systems, next-generation sequencing, and investigative genetic genealogy. The application of these approaches within NDIS has been subject to evolving legal standards, agency policies, and oversight requirements.




Bibliography

Butler, John M. Forensic DNA Typing: Biology, Technology, and Genetics of STR Markers. 2nd ed., Elsevier Academic Press, 2005.

Lazer, David, editor. DNA and the Criminal Justice System: The Technology of Justice. MIT Press, 2004.

Lee, Henry C., and Frank Tirnady. Blood Evidence: How DNA Is Revolutionizing the Way We Solve Crimes. Perseus, 2003.

Wickenheiser, Ray A. “Expanding DNA Database Effectiveness.” Forensic Science International Synergy, 5 Apr. 2022, doi:10.1016/j.fsisyn.2022.100226. Accessed 17 Dec. 2025.

"Frequently Asked Questions on CODIS and NDIS ." Federal Bureau of Investigation, www.fbi.gov/how-we-can-help-you/dna-fingerprint-act-of-2005-expungement-policy/codis-and-ndis-fact-sheet. Accessed 23 Dec. 2025.

Federal Bureau of Investigation. “Federal DNA Identification Act.” Federal Bureau of Investigation, le.fbi.gov/science-and-lab/biometrics-and-fingerprints/codis/federal-dna-identification-act. Accessed 17 Dec. 2025.

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