CODIS Network

Due to the nature of violent and sex-related crimes, there is often an exchange of bodily fluids from which to obtain valuable forensic evidence. Once the biological evidence is collected, it is sent to the crime laboratory for analysis. At the Alabama Department of Forensic Sciences Laboratories, through the use of DNA analyses, it is often possible to determine the original donor of the biological evidence.



The Alabama Department of Forensic Sciences is an integral member of the COmbined DNA Index System (CODIS) project. The CODIS system provides a framework for storing, maintaining, tracking, and searching DNA specimen information. The purpose of the system is to create a national information repository where law enforcement professionals can exchange DNA information. CODIS allows various law enforcement agencies to cross-reference their DNA information with that of other agencies around the country. This "cross-referencing" has the potential of producing DNA matches and linking previously unrelated cases. The CODIS project is currently implemented in 45 states, encompassing greater than 90% of the U.S. population.


CODIS currently consists of three distinct geographic levels: National, State, and Local.

  • National DNA Index System (NDIS)
  • State DNA Index System (SDIS)
  • Local DNA Index System (LDIS)

NDIS is maintained by the Federal Bureau of Investigation (F.B.I.). Each member state has one designated SDIS location, with each participating forensic science agency maintaining a local (LDIS) database. Within the Alabama Department of Forensic Sciences, the SDIS database is located within the Birmingham Regional Laboratory, with LDIS databases located in the Huntsville, Birmingham, Montgomery, and Mobile Regional Laboratories.

Currently each CODIS database is comprised of three distinct indexes, Casework, Convicted Offender, and Population. Law enforcement agencies utilize the Casework and Convicted Offender indexes to search for matching DNA profiles. This enables the Alabama Department of Forensic Sciences to link previously unrelated serial cases, as well as identify perpetrators in "unknown suspect" cases by searching the DNA profile of the crime scene biological evidence against the DNA profiles of previously convicted felons maintained within the Convicted Offender index.

The Alabama Department of Forensic Sciences Convicted Offender Index contains DNA profiles from individuals convicted of certain felony offenses, and who have submitted a blood sample in compliance with Code of Alabama (1975) 36-18-20.

The Alabama Department of Forensic Sciences generates the DNA profiles that are maintained within CODIS utilizing both RFLP and PCR based DNA technologies. ADFS currently has the largest repository of PCR based DNA profiles within the Convicted Offender Index of any CODIS member agency. Since it's implementation within the State of Alabama in 1995 ADFS has already seen successes in linking previously unrelated serial rape cases, identifying the perpetrator in unsolved rape cases, as well as identifying the perpetrator in an unsolved 1990 rape/homicide case.