The Combined DNA Index System, or CODIS, blends forensic science and computer technology into a tool for linking violent crimes. It enables federal, state, and local forensic laboratories to exchange and compare DNA profiles electronically, thereby linking serial violent crimes to each other and to known offenders. Using the National DNA Index System of CODIS, the National Missing Persons DNA Database also helps identify missing and unidentified individuals.
CODIS generates investigative leads in cases where biological evidence is recovered from the crime scene. Matches made among profiles in the Forensic Index can link crime scenes together, possibly identifying serial offenders. Based upon a match, police from multiple jurisdictions can coordinate their respective investigations and share the leads they developed independently. Matches made between the Forensic and Offender Indexes provide investigators with the identity of suspected perpetrators. Since names and other personally identifiable information are not stored at NDIS, qualified DNA analysts in the laboratories sharing matching profiles contact each other to confirm the candidate match.
The FBI Laboratory’s CODIS began as a pilot software project in 1990, serving 14 state and local laboratories. The DNA Identification Act of 1994 formalized the FBI’s authority to establish a National DNA Index System (NDIS) for law enforcement purposes. Today, over 190 public law enforcement laboratories participate in NDIS across the United States. Internationally, more than 90 law enforcement laboratories in over 50 countries use the CODIS software for their own database initiatives.
The CODIS Unit manages CODIS and NDIS. It is responsible for developing, providing, and supporting the CODIS program to federal, state, and local crime laboratories in the United States and selected international law enforcement crime laboratories to foster the exchange and comparison of forensic DNA evidence from violent crime investigations. The CODIS Unit also provides administrative management and support to the FBI for various advisory boards, Department of Justice grant programs, and legislation regarding DNA.
Program managers, forensics system program managers, biologists, auditors, management and program analysts, and paralegal specialists.
Through the combination of increased federal funding and expanded database laws, such as the DNA Fingerprint Act of 2005, the number of profiles in NDIS has and will continue to dramatically increase, resulting in a need to re-architect the CODIS software. A considerable focus during this time will be to enhance kinship analysis software for use in identifying missing persons. This next generation of CODIS will utilize STR and mtDNA information as well as metadata (such as sex, date of last sighting, age, etc.) to help in the identification of missing persons. The re-architecture will also enable CODIS to include additional DNA technologies, such a Y Short Tandem Repeat (Y-STR) and mini-Short Tandem Repeat (miniSTR). The FBI Laboratory is committed to the support of the CODIS program. With the continued cooperation and collaboration of legislative bodies and all components of the criminal justice community—law enforcement, crime laboratories, victims, prosecutors, and the judiciary—the future of DNA, CODIS, and NDIS holds even greater promise to solve crime and identify missing persons.
Frequently asked questions about the CODIS program and the National DNA Index System.
The National DNA Index System's statistical information broken down by state and other NDIS participants.
The DNA Identification Act of 1994 required the formation of a panel of distinguished professionals, from the public and private sectors, to address issues relevant to forensic DNA applications. This panel, titled the DNA Advisory Board (DAB), first convened in 1995. An early mission of the DAB was to develop and implement quality assurance standards for use by forensic DNA testing laboratories. The scope was quickly expanded to include forensic DNA databasing laboratories as well. The DAB fulfilled this role, recommending separate documents detailing quality assurance standards for both applications.
The Quality Assurance Standards for Forensic DNA Testing Laboratories and the Quality Assurance Standards for DNA Databasing Laboratories were first issued by the Director of the FBI in October 1998 and April 1999, respectively. Both documents have become benchmarks for assessing the quality practices and performances of DNA laboratories throughout the country. When the DAB’s statutory term expired, it transferred responsibility for recommending revisions of these quality assurance standards to the Scientific Working Group on DNA Analysis Methods (SWGDAM).
The DNA Identification Act of 1994 also required that the FBI Laboratory ensure all DNA laboratories that are federally operated, receive federal funds, or participate in the National DNA Index System (NDIS) demonstrate compliance with the standards issued by the FBI. Typically, documentation of a laboratory’s compliance with a stated standard has been measured through an audit process. Such audits have been performed by forensic scientists, either internal or external to the laboratory, and serve to identify compliance with established standards.
The audit document defines and interprets each standard, with added discussion points clarifying the criteria necessary for compliance. Additionally, the document is structured such that criteria, which overlap between the FBI-issued standards and the corresponding American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB) elements, share a consistent interpretative view.
Active with the September 2011 audit documents and for audits conducted in accordance with the Quality Assurance Standards (QAS) effective September 1, 2011, separate audit documents will be used for forensic and databasing laboratories.
Coinciding with the revision of the FBI Director’s Quality Assurance Standards and an examination of the procedures for operation of the National DNA Index System (NDIS), the FBI Laboratory impaneled a CODIS Core Loci Working Group in May 2010 to evaluate the necessity for additional loci. Almost 12 years earlier, the FBI’s original STR Standardization Project had recommended the 13 CODIS core loci required (and still being used) for DNA data uploaded to NDIS. Despite the different environments in which the original STR Project and the current working group were and are operating, both recognized the importance of balancing the privacy issues attendant to storing genetic information with ensuring the effectiveness of CODIS to assist criminal investigations. Among its first tasks, the current working group recommended criteria for acceptance of any new CODIS loci, including no known association to medical conditions or defects (this refers to whether or not the loci is diagnostic of any known medical condition or disease status).1
In a letter to the editor of Forensic Science International Genetics announcing the proposed additional loci under consideration for CODIS, the working group identified the following three factors in support of expanding the current CODIS core loci: 1) facilitates greater discrimination, 2) assists in missing person investigations, and 3) encourages international data sharing efforts by having more loci in common with other countries for comparison purposes.2 The chairperson of the working group updated the DNA community on the selection of the potential additional CODIS core loci at the 22nd International Symposium on Human Identification, the 15th- 17th National CODIS Conferences, the European Network of Forensic Science Institutes’ 2011 DNA Working Group meetings, and the 2011 semiannual meetings of the Scientific Working Group on DNA Analysis Methods (SWGDAM). As the working group addressed the validation and implementation phases of the project, the attached process and timeline for determination of additional CODIS core loci were developed to keep the community apprised of the group’s progress and provide an outline for what remained to be accomplished. The working group held discussions with STR kit manufacturers (subject to non-disclosure agreements) on the development of STR kits that incorporate some or all of these proposed loci. Additionally, the working group identified the following statutory and operational requirements for adding new loci:
- The Federal DNA Identification Act of 1994 [42 U.S.C. §14132] requires compliance with the quality assurance standards issued by the FBI Director. The Quality Assurance Standards for Forensic DNA Testing and DNA Databasing Laboratories define the minimum requirements for validation.
- The Justice for All Act [Pub. Law 108-405 §203(f)] requires that the Department of Justice provide Congress with notice of the proposed use of new core markers 180 days in advance of any such implementation.
- Operational Procedures for the National DNA Index System (NDIS) also contain minimum criteria for approval of additional loci or kits that will be acceptable at NDIS, such as concordant studies, mixed samples, non-probative samples, population studies, and precision studies.
Process for Determination of Additional CODIS Core Loci
Selection of Laboratories to Participate in Validation Studies
- Based upon recommendations from the CODIS Core Loci Working Group, the FBI will select laboratories representative of the forensic DNA community (i.e., casework, database, missing person, instrument platforms, kits, etc.), to participate in a validation project for the proposed CODIS core loci using criteria derived from the Quality Assurance Standards and NDIS Procedures.
- Participating laboratories will be responsible for:
- Management approval of participation agreement
- Dedicated personnel for the length of the project
- Instruments required for the validation
- Samples for analysis
- The FBI will be responsible for:
- Costs of the STR kits used by participating laboratories
- Definition and coordination of validation experiments, data evaluation, and assessment
- Participating laboratories will be responsible for:
Validation of Proposed Additional CODIS Core Loci
- Congress will be notified of the proposed additional CODIS core loci.
- Participating laboratories will conduct validation experiments/studies in accordance with the Quality Assurance Standards.
- Successful validation efforts will be dependent on as-yet-undetermined factors, such as:
- Ability of kit manufacturers to make robust versions of kits available for purchase
- Ability to include additional loci within existing 5-dye chemistry
- Ability to configure existing instruments to run 6-dye chemistry
- Separate validation tracks for casework and known database samples
- Availability of federal funding
- Compilation, review, and evaluation of validation results.
- Feedback to kit manufacturers and incorporation of any resulting changes to kits in the validation plan.
- Publication or posting of the validation results.
- Ongoing progress reports to DNA community and other stakeholders.
Selection of CODIS Core Loci
- Input will be obtained from, and progress reports provided to, the DNA community and other stakeholders.
- Assessment and selection of new CODIS core loci will be performed.
Implementation of New CODIS Core Loci into NDIS Operations
- The DNA community will be involved in review and development of the following:
- Ongoing progress reports
- Sufficient lead time necessary for implementation
- Searching Strategies
- Match Strategies
- Confirmation Strategies
- Congress will be notified of the new CODIS core loci required for upload and searching at NDIS.
Updated Timeline for Determination of Additional CODIS Core Loci
Form a Working Group (WG) to discuss initial selection
Establishes target goals
CODIS Core Loci Working Group with FBI Chair and 5 members; Web meetings
May 2010 - present
Announce proposed additional CODIS core loci
Sets desired target goals and informs manufacturers
WG Chair; Publish proposed listing of CODIS core loci
April 2011 online (published Jan 2012)
Ongoing Progress Reports
Provides updates for DNA community
WG Chair; Present updates on status of CODIS Core Loci project at meetings
Implementation Considerations & Strategy
Identify issues for implementation and timeline
June 2011 - present
Manufacturers develop prototype kits
Creates tools to meet target goals
Manufacturers; Provide status reports to WG for timeline
Test and validate prototype kits
Examines if target goals can be met
Validation Laboratories; Follow QAS compliant validation plan
Review and evaluate data from validation
Evaluates if desired performance is obtained
NIST, SWGDAM and FBI; Provide feedback, if any, to Manufacturers
In conjunction with and at the conclusion of validation (2013-2014)
Selection of new CODIS core loci
Allows protocols to be established
FBI; seek input from DNA community and stakeholders; Notify Congress
Implementation of new CODIS core loci at the National DNA Index System
Enables target goals to be met
All NDIS-participating labs
January 1, 2017
Twenty CODIS Core Loci
In early 2015, the FBI announced that the validation project for additional CODIS Core Loci had been completed and that an additional seven loci would be added to the CODIS Core effective January 1, 2017.3 The additional seven loci—D1S1656, D2S441, D2S1338, D10S1248, D12S391, D19S433 and D22S1045—along with the original 13 loci, will comprise the new CODIS Core Loci. Below is a listing of the 20 CODIS Core Loci.
- D1S1656 (effective January 1, 2017)
- D2S441 (effective January 1, 2017)
- D2S1338 (effective January 1, 2017)
- D10S1248 (effective January 1, 2017)
- D12S391 (effective January 1, 2017)
- D19S433 (effective January 1, 2017)
- D22S1045 (effective January 1, 2017)
1 For the complete list of criteria, please refer to Expanding the CODIS Core Loci in the United States, D.R. Hares, Forensic Sci. Int. Genet. 6 (2012), e52-e54.
2 This formal notification of the additional loci proposed by the working group for consideration as CODIS core loci was announced in the April 2011 on-line edition of Forensic Science International (FSI) Genetics and published in the January 2012 edition of FSI Genetics (D.R. Hares, Forensic Sci. Int. Genet. 6 (2012), e52-e54). An addendum (in press) is available online (D.R. Hares, Addendum to expanding the CODIS core loci in the United States, Forensic Sci. Int. Genet. (2012), doi:10.1016/j.fsigen.2012.01.003).
3 Selection and implementation of expanded CODIS core loci in the United States, D.R. Hares, Forensic Sci. Int. Genetics 17:33-34 (2015).
The FBI Laboratory’s Combined DNA Index System (CODIS) blends forensic science and computer technology into an effective tool for solving crime.
The FBI Laboratory announced an expansion of the original 13 short tandem repeat (STR) loci that have been the core of NDIS since 1997. Seven additional STR loci have been selected and will be required for upload and searching of DNA profiles at NDIS effective January 1, 2017.
This document from the Scientific Working Group on DNA Analysis Methods (SWGDAM) provides guidelines for the interpretation of DNA typing results from short tandem repeats.
In response to new, commercially available amplification kits that expand the number of loci in a multiplex reaction, the FBI Laboratory has retyped certain population samples to establish allele distributions for the additional loci and is providing the amended allele frequency tables for use by anyone interested in performing comparisons with previously published data.
Discussion Topics for States Considering Familial Searching
- Consider the applicable state laws and regulations governing the DNA databasing program to determine the best legal approach. Because many state laws are silent on the issue of familial searching, it is important to have a full legal review to evaluate whether familial searching is authorized in your jurisdiction. Those states which have adopted or rejected familial searching have done so under a variety of authorities:
- Several states perform familial searching with the approval of state officials—for example, California implemented its familial search program with the approval of the state attorney general. Other jurisdictions have implemented familial searching based upon an administrative determination or laboratory policy. Two jurisdictions, Maryland and the District of Columbia, currently prohibit, by law, the use of familial searching.
- Implementation of a successful familial search program takes time and requires significant resources and staff. Personnel with an expertise in kinship comparisons are necessary.
- Consider forming a task force to review requests for familial searches as well as to evaluate the familial search results. Such a task force should include laboratory personnel as well as law enforcement personnel and/or prosecutors, who are authorized to access criminal history records for researching background information on potential candidates.
- Because the results generated by familial searching are not the same as CODIS matches, it is important to train law enforcement personnel on the appropriate follow-up, including additional investigative work.
- The current version of CODIS software does not have the capability to efficiently search and return information for familial searching. The states that conduct familial DNA searches use specially-designed software (not CODIS) to conduct these searches.
- As with implementation of any new software, validation is required before use of such software in laboratory operations. Any validation must be conducted in accordance with Standard 8 of the FBI’s Quality Assurance Standards.
- Develop standard operating protocols (SOPs) for familial searching prior to implementation of a familial search program.
- Policies and procedures should be developed and approved prior to implementation and address, at a minimum, the following:
- Privacy considerations
- Release of information
- Criteria for familial search requests:
- Types of crimes eligible for searching
- Types of forensic DNA records eligible for searching
- If all other investigative leads must first be exhausted
- Approval by task force, board, laboratory management, etc.
- Processes for familial search:
- Type of DNA records to be searched (e.g., offenders only, offenders and arrestees
- Frequency of searches
- Use of additional filters for search results (e.g., YSTR testing, metadata)
- Reporting of search results
The FBI administers the National Missing Person DNA Database (NMPDD) as part of the National DNA Index System (NDIS). The NMPDD compares DNA records stored in the Missing Person, Relatives of Missing Person, and Unidentified Human Remains Indexes of NDIS.
Sufficient DNA data from both the human remains and the relatives of the missing person are needed to produce a statistically significant database association involving DNA profiles in a missing persons case. In order to maximize the potential for such associations, as much genetic information as possible should be requested and obtained in a missing person investigation. This may be accomplished by:
- Collecting DNA samples from multiple relatives. Any relative of the missing person offering to provide a DNA sample should have a sample collected. The laboratory will assist in determining which samples should be analyzed and databased;
- Requesting mitochondrial DNA (mtDNA) analysis on at least one maternal relative for all missing person cases, regardless of gender;
- Requesting YSTR analysis on at least one paternal relative if the missing person is a male; and
- Requesting mtDNA analysis on all unidentified human remains and YSTR analysis on male remains.
However, despite these efforts, when limited genetic information is available, associations may not be possible through database searches. Circumstances that may prevent a database association from occurring include:
- The DNA data has not been uploaded to NMPDD/NDIS;
- Insufficient STR results were obtained from the human remains;
- The resulting DNA data contains a mtDNA or YSTR haplotype that is relatively common in the relevant population; or
- There is diminished allele sharing between relatives and remains when first-degree relatives (e.g., parents, offspring, or siblings) are not available to provide a sample.
If a law enforcement agency investigating a case believes that a particular set of remains may be those of a specific missing person, a request for a manual comparison may be warranted. A manual comparison is a direct comparison of the DNA data obtained from specific missing person-related records outside of the routine NMPDD searches. Known reference DNA records, such as offender and arrestee DNA records, are generally not subject to retrieval from CODIS for manual comparison purposes. Missing person reference DNA records, however, may be retrieved from DNA databases (CODIS) for manual comparison because these reference samples were obtained through a voluntary consent process and were contributed solely for the purpose of identifying a missing or unidentified person.
All requests for manual comparison shall be made by the investigating agency directly to the NDIS participating laboratory responsible for the missing person-related DNA records. Non-law enforcement agencies or organizations seeking manual comparisons should direct their requests to the appropriate investigating agency or medico-legal authority to ensure their involvement in this process. NDIS participating laboratories shall not consider a request for a manual comparison of missing person-related records submitted by a non-law enforcement agency or organization. When a laboratory receives a request for a manual comparison, all available information will be reviewed by the laboratory personnel. This includes not only the DNA data, but other case-specific information (metadata), such as the missing person’s date of disappearance, the date the remains were found, the estimated age of the remains, the age of the missing person, and any other identifying features.
Using this information, the NDIS participating laboratory will determine whether a routine search of NMPDD would be expected to produce an association. Based upon this review, the laboratory may, in its discretion, deny the request for a manual comparison. If the genetic information from the human remains and/or relatives is limited, the laboratory may perform the comparison in accordance with its policies and protocols. When a manual comparison cannot exclude the possibility of a positive association, the laboratory will provide a report to the investigating agency that includes the appropriate kinship statistics.
If the DNA data for the human remains and reference samples are maintained by multiple NDIS participating laboratories, the laboratories will collaborate to exchange both DNA data and metadata. Once the comparison has been completed, the participating laboratories will ensure that all involved law enforcement agencies, medico-legal authorities, and laboratories are informed of the results.
Note: Please keep in mind that NDIS participating laboratories do not have the legal authority to declare or confirm the identity of human remains. That determination shall be made by the appropriate medico-legal authority (e.g., medical examiner or coroner).
Guidelines for Requesting a Missing Person Manual Comparison
1. All requests for missing person manual comparisons shall be submitted to the NDIS participating laboratory by the law enforcement agency or medico-legal authority responsible for the case.
2. Non-law enforcement agencies or organizations wishing additional information or a manual comparison shall submit the request to the law enforcement agency or medico-legal authority responsible for the case. That agency/authority will forward the request to the appropriate NDIS participating laboratory. NDIS participating laboratories shall not consider requests received directly from non-law enforcement agencies or organizations.
3. If the DNA data related to the case is maintained by multiple NDIS participating laboratories, the requesting agency shall make reasonable efforts to determine the laboratories involved and provide that information with the request for a manual comparison.
4. The NDIS participating laboratory/laboratories maintaining the relevant DNA profiles shall evaluate the data to determine, in its/their discretion, if a manual comparison is warranted. This evaluation shall include:
- A comparison of metadata related to the individual reported missing and the human remains recovered; and
- A review of the available DNA data for completeness, number of available references, and their relationship to the missing person.
5. In the event of a positive association, all law enforcement agencies and medico-legal authorities involved in the case shall be notified by an NDIS participating laboratory. These participating laboratories shall not provide laboratory reports or notifications to non-law enforcement agencies or organizations.
Questions regarding the Missing Persons program within the NDIS should be directed to the FBI Laboratory’s CODIS Unit at 703-632-8315. Questions regarding a specific case or comparison should be directed to the NDIS participating laboratory that maintains the DNA data.