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Forensic Biology Frequently Asked Questions
A: Samples should be collected in a way that will avoid sample destruction and degradation. Biological evidence is best preserved in a dry, cooler
environment. Items of evidence should be packaged in brown paper sacks, evidence envelopes, or similar packaging material. Biological
evidence should never be packaged in plastic bags.
Note: For more specific packaging information, please, go to: Evidence Collection Manual
A: No. Due to chain of custody issues and the laboratory's desire to communicate with the submitting officer regarding the submission of evidence, the
evidence should be hand delivered to one of the OSBI’s laboratories.
A: A known reference sample is a DNA sample obtained from a particular individual (i.e. buccal swab from a victim or suspect). Known reference
samples should be collected as buccal swabs. A buccal swab is a swabbing of the inside of a person’s cheek and gum area. A sterile swab should
be used when taking a known reference sample. A minimum of two swabs should be used, and these swabs should be taken at the same time. The
swabs should be allowed to air dry in a swab box or another appropriate container. The packaging should be clearly labeled with the individual's
name. The buccal swabs do not need to be refrigerated. Known reference samples from the medical examiner’s office are typically submitted on a
A: Every case is different. Analysis is dependent on the number of samples that were submitted and the current backlog of the laboratory at the
time. The duty biologist or supervisor of the laboratory analyzing the evidence may be contacted to get an estimate of the turn-around time. Estimates
should not be mistaken for guaranteed time frames.
A: In most cases, the amount of sample that is required for DNA analysis is minimal, and every effort is made to keep at least half of the stain for
additional testing if necessary. If a sample will be consumed in testing, the laboratory will contact the assigned officer or District Attorney’s office to
obtain written permission to consume the sample.
A: Yes, if there is no suspect and there is evidence from the crime scene, a DNA profile can be obtained and entered into the Combined DNA Index
System (CODIS) database to attempt to develop an investigative lead. If there is a CODIS hit to an unknown suspect, then a hit letter will be sent
to the investigator. At that time a known buccal swab should be obtained from the individual and submitted to the laboratory. Comparisons will
then be made between the known reference sample and the evidence submitted.
A: The Federal Bureau of Investigation facilitates the use of a national DNA database, which is called the Combined DNA Index System (CODIS)
database. It can be used to search profiles within the state of Oklahoma and throughout the United States. CODIS is a useful tool in providing
investigative leads to law enforcement agencies throughout the state. It is particularly useful when there are no suspects or a suspect has not yet
been developed. CODIS is also providing useful information on cold cases. For more information view the CODIS webpage.
A: Yes, a known buccal swab should be collected and submitted for all suspects identified in a case at the time of submission of evidence to the OSBI
FBU. The CODIS database is for investigative leads only and cannot be used for comparison to cases submitted. Furthermore, CODIS samples do
not follow the same chain of custody as evidentiary samples and cannot be used as known reference samples.
Q: How do I know if the DNA profiles developed in my case were put into CODIS? How do I know if a profile that was previously entered into
CODIS is still being searched?
A: For cases since July 2011, there has either been a statement in the DNA report or a letter sent stating what profiles were entered into CODIS. If you
have any questions regarding a specific case, you can contact the CODIS Unit.
A. No, offender DNA samples/profiles are confidential and cannot be released for use in a civil case. Other samples to consider: paternal grandparents,
paternal (full) siblings, medical samples such as biopsy slides, or teeth.
A. No. The offender collection kits are for the DNA Databank only. They do not have a chain of custody associated with them, and are not considered
evidence. You do not need a special kit to collect a known DNA sample. Using sterile swabs and storing them in a sealed evidence envelope is
A. Offender samples used by the DNA Databank do not have an associated chain of custody, and are generally inadmissible in court. A new sample is
needed to do a direct comparison between the individual listed in the CODIS hit letter and your case. No statistical analysis can be performed without
a known DNA sample.
A. In general:
1. The evidence submitted has to be from a crime scene
Please remember evidence can be informative for your case without being CODIS eligible; for example, victim blood on suspect pants.
For additional guidance or to discuss a specific case, please contact the CODIS Unit.
A: DNA analysis will not be performed on brief contact items. Brief contact items are those items considered unlikely to contain sufficient transfer of
skin cells to the object. Examples of brief contact items would include door handles, counter tops, etc. Touch DNA analysis can be performed on
items that would result in skin cells being left on objects due to extended contact. Examples of Touch DNA extended contact items would include
some clothing, cigarette butts, straws, bottles, cans, etc.
A: Please, read the Notification Regarding Population Statistics in DNA reports.
A: For more information on the program, please go to the main laboratory FAQ's.
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