It's Evident


Using Computer Technology to Solve Cold Cases
Dr. Susan Zucker, Director of Technology and Distance Education

Computer technology is used in forensics to solve cold cases and other crimes in a variety of ways. Advances in DNA analysis coupled with advances in computer technology effectively and efficiently identify subjects, link serial crimes, and exonerate innocent persons. In addition to online databases devoted to DNA profiling, many other electronic databases and resources are important in solving cold and old cases. Other forensic tools, such as ballistics and fingerprint analysis, use computer technologies to aid in solving cold cases and other crimes. Some are online resources, all are described at:

DNA and DNA Technology

Today, cold, old, or previously unsolved criminal cases are often solved using computer technology and DNA analysis. It is now possible to use biological samples which previously were considered too old, too small, or too degraded to create an acceptable DNA profile. Improved databases containing enhanced profiles make use of current biological evidence as well as evidence collected decades ago. A database dedicated to this purpose is CODIS (Combined DNA Index System).

CODIS is a computer index system which consists of a digital network. It is implemented as a distributed database that contains electronic DNA profiles collected from unsolved crime scene evidence, missing persons, and convicted offenders. CODIS connects forensic DNA laboratories at the local, state, and national levels (or tiers). All three levels contain two criminal indices - forensic and convicted offender indices, a missing persons index, and a population file used to generate statistics. (NIJ) CODIS searches the Forensic Index and the Offender Index. A match on the Forensic Index indicates a possible connection between two or more previously unlinked cases. Forensic to Offender Index matches can provide a suspect for an unsolved case. CODIS produces a list of candidate matches which must be verified by a Qualified DNA Analyst. (NIJ)

There is pressure to expand the categories of individuals included in CODIS because higher volume of data enhances the effectiveness of the database. To that end, database statutes in many states are being amended to include less violent criminals in the offender and forensic indices of CODIS. Legislation requiring all convicted felons to submit a DNA profile to the state database is being enacted by many states. These actions dramatically increase the number of convicted offender DNA profiles against which forensic DNA evidence can be compared, making the database system more powerful. (NIJ)

The success and power of CODIS is evident. Thousands of DNA matches have linked serial cases to one another and have been solved by matching crime scene evidence to known convicted offenders, crimes previously thought unsolvable have been solved, and there is evidence to show that improved DNA analysis deters crime. On the flip side, advances in computer technology, DNA analysis, and new legislation concerning DNA profiling, has created convicted offender and forensic casework backlogs, which is a growing problem. As states acknowledge the crime-solving and crime-prevention potential of DNA databases, they continue to expand the scope of their convicted offender legislation, thereby increasing the number of samples to be collected and analyzed by the DNA laboratory. As a result, more than one million uncollected convicted offender DNA profiles are "owed" to the system. (NIJ)

Increased requests from convicted persons and post-arrest/indictment cases seeking to prove their innocence also add pressure to the system especially since there have 197 post-conviction DNA exonerations and tens of thousands of post-arrest/indictment DNA exonerations. (Scheck, 2007) Further, prosecutors are now using database information to issue arrest warrants in the name of John Doe based on DNA profiles. See a description of this process in the Research Extra section of this issue by Catherine M. Guthrie, Killing Time: The Application of John Doe Indictments to Keep Cases Warm.

Breadth of DNA Analysis Use

The use of DNA evidence and convicted offender DNA databases has expanded significantly to include those who commit less violent crimes since the first U.S. DNA database was created in 1989. U.S. Federal Law used to exclude arrestees and suspects unless they were felons previously convicted of serious crimes. Offenders include adult convicts, delinquent juveniles, and other non-convicts (arrestees and suspects). The DNA Identification Act of 1994 specifically prohibited arrestee testing until post-conviction, but the success of DNA databases has resulted in a national trend toward database expansion. (Axelrad, 2004)

All 50 states today, as well as the FBI, “collect DNA samples from convicted offenders, retain the profiles generated from those samples in databases, and compare the database entries against DNA profiles of biological evidence. Most states now require DNA samples from all convicted felons and juveniles adjudicated delinquent for certain offenses.” (Axelrad, 2004) State DNA database statutes, universally directed at sex and violent offenders, have gradually expanded the boundaries in which DNA database statutes operate. This is an attempt to balance the database’s practical advantages with the financial costs, privacy concerns, and fairness concerns associated with DNA profiling. (Axelrad, 2004)

Thirty-four states require all felons to submit DNA for purposes of DNA profiling. Other states make any “crime”, defined as an offense punishable by more than six months imprisonment, the criterion for inclusion. Many states also include some misdemeanors as qualifying offenses. These generally consist of violent and/or sexual offenses.

On the international front, many countries take a DNA sample when an arrest is made and put the information into a searchable database. China, India and Brazil are developing databases and the United Kingdom databases all recordable offenses, except traffic violations. If a person is acquitted, the government apologizes but the DNA is kept in the database. Those decisions have been challenged all the way to the European Commission on Human Rights and challengers have won.

Interpol has a database system which allows the United States to check data from other countries. Although not yet very effective, it may be some day. The European Schengen III Treaty Conductivity Scheme (1985) was established to allow individual European countries to begin searching each others’ databases. (Asplen, 2006)

Other Databases and Resources

Many online databases and resources are used to help solve cold cases and other crimes and to house and classify forms of evidence, other than DNA profiles in CODIS. Other technologies, such as improved ballistics and fingerprint databases, also advance cases. There are online databases which coordinate/provide:
  • fingerprint services (IAFIS - Integrated Automated Fingerprint Identification System)
  • search and rescue (Canine SARTECH Resource Database posted by NASAR - National Association for Search and Rescue)
  • assistance for solving cold cases, including the creation and maintenance of a centralized case data repository for information on child disappearances, abductions, homicides, and serial murders (CASMIRC - Child Abduction and Serial Murder Investigative Resources Center)
  • unexplained disappearances and unidentified persons and a searchable database of related resources (The Doe Network)
  • financial intelligence specifically related to terrorist financing and money laundering (FinCEN - Financial Crimes Enforcement Network)
  • information on skeletal, cranial, and dental records for biometric comparison, and forensic discriminate function database (FORDISC), which uses forensic measurements to classify unknown cranial remains (FDB - The Forensic Anthropology Data Bank)
  • posters of missing and abducted children and sharing these images with other law enforcement agencies (LOCATER – The Lost Child Alert Technology Resource) nonfatal and mortal injury data and a searchable interactive injury mapping system (NCIPC - National Center for Injury Prevention and Control) of the CDC
  • criminal justice information hosted by the FBI (NCIC – National Crime Information Center)
  • index tool of CODIS for linking crime scenes and identifying offenders in an effort to coordinate investigative leads from DNA evidence indexed from multiple jurisdictions (NDIS – National DNA Index System)
  • stored data relating to emergency contacts, next of kin, and vital medical information (NOKR – Next of Kin Registry)
  • database sponsored by volunteer artists to assist law enforcement agencies with the creation of facial reconstructions (Project Edan)
  • database of dental and pathological information for the purpose of locating matches by forensic analysts and law enforcement agencies (WinID3: Dental Identification System)
For a more complete list, descriptions, and database locations, see NCSTL’s Cold Case Toolkit at

Other Computer Technology Applications

Many other computer-based technologies aid in solving cold cases and other crimes. Some are online resources which:
  • help to find funding for solving cold cases with DNA
  • provide instruction on how cold case squads work
  • provide internet-based resources and a clearinghouse of posted image databases to aid in the solving of cold cases, including photograph age progression, facial image reconstruction, fingerprint identification, handwriting analysis, and browser-based dashboard access to technology resources for law enforcement officers (NCMEC - National Center for Missing and Exploited Children)
  • focus on the use of ballistic identification digital imaging equipment to compare firearm and tool mark evidence (NIBIN - National Integrated Ballistic Information Network)
  • provide data processing services
  • provide scientific and investigative support to assist with solving cases involving hidden evidence and human remains (NecroSearch)
  • offer data processing services
  • apply the technology of the Video Image Stabilization and Registration (VISAR), a system that stabilizes and enhances video quality by providing clear and identifiable crime scene footage (Video Analyst)
  • provide technological and laboratory tests of biological and DNA evidence,providing law enforcement agencies with evidence analysis in a format conducive to uploading onto CODIS (Orchid Cellmark - Cold Case DNA Screening Service)
See NCSTL’s Cold Case Toolkit at

Asplen, C. and Corazon DeUngria, M. The Impact of DNA Evidence In Addressing Human Rights Issues in the Philippines and Other Uses of DNA Worldwide, Last viewed on March 28, 2007.

Axelrad, S. Survey of State DNA Database Statutes, 2004, Last viewed on March 28, 2007.

Department of Forensic Science, Commonwealth of Virginia,, Last viewed on March 28, 2007.

DNA Technology in Forensic Science, Last viewed on March 28, 2007.

Kirkpatrick, M.D. Cold Cases with Digital Fingerprints, Sheriff, July-August 2001, at 14, Last viewed on March 28, 2007.

Lewis, C. Solving the Cold Case: Time, DNA and Ingenuity Can Help, Court TV News: Hidden Traces. Last viewed on March 28, 2007.

National Institute of Justice (NIJ). Using DNA to Solve Cold Cases, July, 2002, Series: Special Report, Last viewed on March 28, 2007.

Scheck, B. Innocence Project, Talk at Stetson University College of Law, Gulfport, FL, March 27, 2007.

Technology Needs Identified by the DNA Forensics Technology Working Group, Last viewed on March 28, 2007.