Evidence Examinations
DNA Examinations
Deoxyribonucleic acid (DNA) is analyzed in
body fluids, stains, and other biological tissues recovered from evidence.
The results of DNA analysis of questioned biological samples are compared
with the results of DNA analysis of known samples. This analysis can
associate victim(s) and/or suspect(s) with each other or with a crime
scene.
Blood
Examinations
Examinations can determine the presence or
absence of blood in stains. Examinations can also determine whether blood
is human or nonhuman and can determine the animal species. Blood
examinations cannot determine the age or the race of a person.
Conventional serological techniques are not adequately informative to
positively identify a person as the source of a stain.
Collecting Known Samples
Blood
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Only qualified medical personnel should
collect blood samples from a person.
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Collect at least two 5-mL tubes of
blood in purple-top tubes with EDTA as an anticoagulant for DNA
analysis. Collect drug or alcohol testing samples in gray-top tubes with
NaF (sodium fluoride).
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Identify each tube with the date, time,
subject's name, location, collector's name, case number, and evidence
number.
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Refrigerate, do not freeze blood
samples. Use cold packs, not dry ice during shipping.
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Pack liquid blood tubes individually in
StyrofoamJ or cylindrical tube containers with absorbent
material surrounding the tubes.
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Label the outer container KEEP IN A
COOL DRY PLACE, REFRIGERATE UPON ARRIVAL, and
BIOHAZARD.
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Submit to the Laboratory as soon as
possible.
Saliva
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Use clean cotton swabs to collect
saliva samples. Rub the inside surfaces of the cheeks and gums
thoroughly. Air dry the swabs and place in clean paper or an envelope
with sealed corners. Do not use plastic containers.
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Identify each sample with the date,
time, subject's name, location, collector's name, case number, and
evidence number.
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Saliva samples do not need to be
refrigerated.
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Submit to the Laboratory as soon as
possible.
Documenting, Collecting, Packaging, and Preserving DNA
Evidence
If DNA evidence is not properly
documented, collected, packaged, and preserved, it will not meet the legal
and scientific requirements for admissibility in a court of
law.
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If DNA evidence is not properly
documented, its origin can be questioned.
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If it is not properly collected,
biological activity can be lost.
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If it is not properly packaged,
contamination can occur.
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If it is not properly preserved,
decomposition and deterioration can occur.
When DNA evidence is transferred by direct
or secondary (indirect) means, it remains on surfaces by absorption or
adherence. In general, liquid biological evidence is absorbed into
surfaces, and solid biological evidence adheres to surfaces. Collecting,
packaging, and preserving DNA evidence depends on the liquid or solid
state and the condition of the evidence.
The more that evidence retains its
original integrity until it reaches the Laboratory, the greater the
possibility of conducting useful examinations. It may be necessary to use
a variety of techniques to collect suspected body fluid
evidence.
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Submitting DNA Evidence
Questions concerning DNA evidence should be directed to 03-9702366. Follow the Evidence
Submission directions including Requesting
Evidence Examinations and Packaging
and Shipping Evidence.
Blood
on a Person
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Absorb suspected liquid blood
onto a clean cotton cloth or swab. Leave a portion of the cloth or swab
unstained as a control. Air dry the cloth or swab and pack in clean
paper or an envelope with sealed corners. Do not use plastic
containers.
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Absorb suspected dried blood
onto a clean cotton cloth or swab moistened with distilled water. Leave
a portion of the cloth or swab unstained as a control. Air dry the cloth
or swab and pack in clean paper or an envelope with sealed corners. Do
not use plastic containers.
Blood on Surfaces or
Water
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Absorb suspected liquid blood or
blood clots onto a clean cotton cloth or swab. Leave a portion of
the cloth or swab unstained as a control. Air dry the cloth or swab and
pack in clean paper or an envelope with sealed corners. Do not use
plastic containers.
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Collect suspected blood in snow or
water immediately to avoid further dilution. Eliminate as much snow
as possible. Place in a clean airtight container. Freeze the evidence
and submit as soon as possible to the Laboratory.
Bloodstains
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Air dry wet bloodstained
garments. Wrap dried bloodstained garments in clean paper. Do not
place wet or dried garments in plastic or airtight containers. Place all
debris or residue from the garments in clean paper or an envelope with
sealed corners.
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Air dry small suspected wet
bloodstained objects and submit the objects to the Laboratory.
Preserve bloodstain patterns. Avoid creating additional stain patterns
during drying and packaging. Pack to prevent stain removal by abrasive
action or packaging materials during shipping. Pack in clean paper. Do
not use plastic containers.
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When possible, cut a large sample of
suspected bloodstains from immovable objects with a clean sharp
instrument. Collect an unstained control sample. Pack to prevent stain
removal by abrasive action or packaging materials during shipping. Pack
in clean paper. Do not use plastic containers.
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Absorb suspected dried bloodstains
on immovable objects onto a clean cotton cloth or swab moistened
with distilled water. Leave a portion of the cloth or swab unstained as
a control. Air dry the cloth or swab and pack in clean paper or an
envelope with sealed corners. Do not use plastic containers.
Blood Examination Request Letter
A blood examination request letter should
contain the following information:
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A brief statement of facts relating to
the case.
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Claims made by the
suspect(s) regarding
the source of the blood.
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Whether animal blood is
present.
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Whether the stains were laundered or
diluted with other body fluids.
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Information regarding the
victim(s)'
and suspect(s)' health, such as AIDS, hepatitis, or tuberculosis.
Semen and Semen Stains
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Absorb suspected liquid semen
onto a clean cotton cloth or swab. Leave a portion of the cloth or swab
unstained as a control. Air dry the cloth or swab and pack in clean
paper or an envelope with sealed corners. Do not use plastic
containers.
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Submit small suspected dry
semen-stained objects to the Laboratory. Pack to prevent stain
removal by abrasive action or packaging materials during shipping. Pack
in clean paper. Do not use plastic containers.
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When possible, cut a large sample of
suspected semen stains from immovable objects with a clean sharp
instrument. Collect an unstained control sample. Pack to prevent stain
removal by abrasive action or packaging materials during shipping. Pack
in clean paper. Do not use plastic containers.
-
Absorb suspected dried semen stains
on immovable objects onto a clean cotton cloth or swab moistened
with distilled water. Leave a portion of the cloth or swab unstained as
a control. Air dry the swab or cloth and place in clean paper or an
envelope with sealed corners. Do not use plastic containers.
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Seminal Evidence From Sexual Assault
Victim(s)
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Sexual assault victim(s) should be
medically examined in a hospital or a physician's office using a
standard sexual assault evidence kit to collect vaginal, oral, and anal
evidence.
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Refrigerate and submit the evidence as
soon as possible to the Laboratory.
Saliva
and Urine
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Absorb suspected liquid saliva or
urine onto a clean cotton cloth or swab. Leave a portion of the
cloth unstained as a control. Air dry the cloth or swab and pack in
clean paper or an envelope with sealed corners. Do not use plastic
containers.
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Submit suspected small, dry saliva-
or urine-stained objects to the Laboratory. Pack to prevent stain
removal by abrasive action or packaging materials during shipping. Pack
in clean paper or an envelope with sealed corners. Do not use plastic
containers.
-
When possible, cut a large sample of
suspected saliva or urine stains from immovable objects with a
clean sharp instrument. Collect an unstained control sample. Pack to
prevent stain removal by abrasive action or packaging materials during
shipping. Pack in clean paper. Do not use plastic
containers.
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Pick up cigarette butts with
gloved hands or clean forceps. Do not submit ashes. Air dry and place
the cigarette butts from the same location (ashtray) in clean paper or
an envelope with sealed corners. Do not submit the ashtray unless latent
print examination is requested. Package the ashtray separately. Do not
use plastic containers.
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Pick up chewing gum with gloved
hands or clean forceps. Air dry and place in clean paper or an envelope
with sealed corners. Do not use plastic containers.
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Pick up envelopes and stamps
with gloved hands or clean forceps and place in a clean envelope. Do not
use plastic containers.
Hair
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Pick up hair carefully with clean
forceps to prevent damaging the root tissue.
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Air dry hair mixed with suspected body
fluids.
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Package each group of hair separately
in clean paper or an envelope with sealed corners. Do not use plastic
containers.
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Refrigerate and submit as soon as
possible to the Laboratory.
Tissues, Bones, and Teeth
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Call the Laboratory at 03-9702366 prior to submitting suspected
tissues, bones, or teeth to ensure that the evidence will be accepted by
the Laboratory. The communication accompanying the evidence must
reference the telephone conversation accepting the
evidence.
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Pick up suspected tissues, bones, and
teeth with gloved hands or clean forceps.
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Collect 1-2 cubic inches of red
skeletal muscle.
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Collect 3-5 inches of long bone such as
the fibula or femur.
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Collect teeth in the following
order:
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non-restored molar
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non-restored premolar
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non-restored canine
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non-restored front
tooth
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restored molar
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restored premolar
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restored canine
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restored front
tooth
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Place tissue samples in a clean,
airtight plastic container without formalin or formaldehyde. Place teeth
and bone samples in clean paper or an envelope with sealed
corners.
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Freeze the evidence, place in
Styrofoam containers, and ship overnight on dry
ice.
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