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Forensic Biology FAQ

General Questions

  • Who is required to provide a sample for entry of the resulting DNA profile into the Virginia DNA Data Bank?

  • Every person required to register for the Sex Offender and Crimes Against Minors Registry (Code of Virginia § 9.1-903), all individuals who have been convicted of a felony offense on or after July 1, 1990  or certain misdemeanors (Code of Virginia § 19.2-310.2), and juveniles 14 years or older who are convicted of a felony or adjudicated delinquent on the basis on an act which would be a felony if committed by an adult (Code of Virginia § 16.1-299.1) are required to provide a blood or buccal (cheek cells) sample for DNA analysis, with incorporation of the resulting DNA profile into the Virginia DNA Data Bank. Additionally, as of January 1, 2003, any individual arrested for a violent felony crime (Code of Virginia § 19.2-310.2:1) must provide a buccal sample for DNA analysis, with the resultant profile incorporated into the Virginia DNA Data Bank (Code of Virginia § 19.2-310.5).  Inclusion in the DNA data bank may also be ordered pursuant to plea agreement in Circuit Court.

  • What is CODIS?

  • CODIS stands for Combined DNA Index System. It is a national system of computer databases designed by the FBI to store DNA profiles from individuals as well as crime scene evidence. Any DNA profile developed from the evidence in a case with no suspects can then be searched against the databases, and possible investigative leads developed from any matching profiles in the database.

  • On what types of cases can a CODIS search be conducted?

  • CODIS searches can be conducted on the DNA profiles developed from biological evidence in cases where the identity of the perpetrator is unknown to the investigator. In theory, any biological material could yield a DNA profile if there is a sufficient number of cells from the perpetrator.

  • What does a CODIS "hit" mean?

  • A CODIS "hit" can be made by a DNA profile from evidence in an unsolved case matching the DNA profile from a convicted offender or an arrestee. A "hit" can also be made between evidence in an unsolved case and another unsolved case or to a previously solved case. The fact that the DNA profiles matched is meant to provide an investigative lead to the detective or investigator, to help solve the particular unsolved case. He/she will need to conduct further investigation to determine any possible involvement of the convicted offender, arrestee, or the perpetrator of the solved case to the unsolved case in question.

  • What DNA technology does DFS use when analyzing evidence from criminal cases?

  • For autosomal DNA testing, the Virginia Department of Forensic Science currently uses Promega's PowerPlex® Fusion System, which includes the  D3S1358, D1S1656, D2S441, D10S1248, D13S317, D16S539, D18S51, D2S1338, CSF1PO, TH01, vWA, D21S11, D7S820, D5S818, TPOX, D8S1179, D12S391, D19S433, D22S1045, and FGA plus Penta E, Penta D, DYS391 and Amelogenin loci.

  • What types of samples are typically subjected to Mitochondrial DNA testing?

  • Bone samples and hair shafts are typically tested with Mitochondrial DNA.

  • Why are statistics provided in DNA reports?

  • The statistic provides an estimate for how common or rare the DNA type is estimated to be in the general population.

  • Can DNA testing be conducted without reference samples?

  • Yes, DNA testing can be conducted without reference samples. However, if reference samples are available they are encouraged to be submitted to the laboratory.

  • When should a PERK be submitted to the laboratory for analysis?

  • Pursuant to Virginia Code § 19.2-11.8, a law-enforcement agency that receives a physical evidence recovery kit (PERK) collected from a victim who has reported the offense shall submit the physical evidence recovery kit to DFS for analysis within 60 days of receipt, except under the following circumstances: (i) it is an anonymous PERK; (ii) the PERK was collected by the Office of the Chief Medical Examiner as part of a routine death investigation, and the medical examiner and the law-enforcement agency agree that analysis is not warranted; (iii) the PERK is connected to an offense that occurred outside of the Commonwealth; (iv) the PERK was determined by the law-enforcement agency not to be connected to a criminal offense; or (v) another law-enforcement agency has taken over responsibility for the investigation related to the physical evidence recovery kit.

Law Enforcement Questions

  • What do I do if I have a court date and have not received a DNA report on the evidence I submitted?

  • If you have not received a report on a case and find out that a court date has been set, notify the examiner/Forensic Biology Section as soon as possible. This will help ensure that the analysis can be completed in advance of the 21 day rule which applies to DNA analysis.

  • How can I get my case searched in the Virginia DNA Data Bank?

  • If you have a case in which there is biological material identified, but you have no suspect, the case will be searched against the DNA Data Bank. If there is a "hit" against an individual, you will receive a report stating the offender's name and other identifying information. If there is a "hit" against the DNA profile of crime scene material from another case, you will receive a report stating the FS Laboratory Number and jurisdiction of the related case. If there is not a hit, you will receive a report stating this. These cases are routinely searched as the DNA Data Bank is updated with new  profiles.

  • I have an old case that is still unsolved. Is there anything that can be done now that could help clear the case?

  • If you have an old, unsolved case that you would like to resubmit for re-evaluation, please call the Forensic Biology Section prior to submission. The case file will be retrieved and reviewed so that both the examiner and officer can discuss the possible course of analysis that could be conducted prior to the re-submission of the evidence. This communication also enables the officer to know which items of evidence to resubmit to the laboratory.

  • What paperwork is required by DFS for submission of family reference samples or an alternate known in a Missing Persons case?

  • DFS recommends the use of the Missing Person Family Reference Collection Kits. These kits can be obtained at any of the Regional Laboratories or Medical Examiner’s offices. Follow the instructions provided with the kits, and submit along with a completed Request for Laboratory Examination (RFLE). If you do not have the Missing Person Family Reference Collection Kits, download and complete this document for each reference sample being collected, and submit along with the reference samples/alternate known and a completed RFLE.