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.
WHAT IS CODIS?
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.
WHERE IS CODIS?
CODIS currently consists of three distinct geographic levels: National, State,
- 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