Transcript Breaking Down the Double Helix: Crime Labs and Post

Breaking Down the Double Helix:
A Crime Lab Perspective on Post-Conviction
DNA Testing
Dean M. Gialamas
President, American Society of Crime Laboratory Directors (ASCLD)
Director, Orange County Sheriff-Coroner Forensic Science Services Division
NIJ DNA Case Management Symposium
January 22, 2009
Palm Harbor, FL
DNA and Post-Conviction Cases
• No single forensic discipline has had more
impact on post-conviction cases than DNA
• Technology advancement has brought a sense of
both excitement and disappointment to the
criminal justice community
• Databases, and in particular the sharing of
information, has been the most remarkable
impact to solving (and preventing) crime in
forensic science
Crime Lab Post-Conviction Issues
• Case identification and evaluation
• Locating and preserving evidence
▫ Case record review
• Laboratory testing
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Evidence selection
Technology selection
Laboratory selection
Database “technology”
Reporting and notification
Locating and Preserving Evidence
• Locate and review evidence chain of custody documentation
▫ Evidence may also be in courts, police property rooms, hospitals,
medical examiner offices, and private labs
• Locate and review the laboratory case file, including all crime scene
and laboratory reports and notes
▫ Previously prepared sample splits
▫ Sample extracts remaining from original or previous lab analyses
▫ Determine if other laboratory analyses would have evidence
remaining (e.g., micro slides)
• Also consider the need for reference samples
▫ May need to obtain secondary reference samples
• Communication and collaboration with the local crime lab may be
key in locating evidence
Laboratory Testing
• Evidence Selection
▫ Determine what probative question needs to be answered
and if the current state of technology can answer that
question
 Evidence may not be limited to items previously examined –
may include samples not tested, biological samples previously
not detected, or samples previously unsuitable for testing
▫ DNA is not the “be all” technology
 Determine if other forensic disciplines can answer the
probative question
 Other disciplines may corroborate/refute witness testimony or
may be faster, cheaper
▫ Use your experts to assist – whether a local crime lab or
privately retained
Laboratory Testing
• Technology Selection
▫ Determine what technology
was previously used and the
conclusions formed (e.g., inconclusive results)
▫ Determine if and/or what current technology will
answer the probative questions (e.g., nuclear-STR’s,
Y-STR’s, mt-DNA, mini-STR’s)
▫ Consider touch/trace DNA sampling and testing
▫ Consider non-traditional DNA samples for testing
Traditional Sources of DNA
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Blood
Semen
Vaginal fluid
Saliva
Skin tissue
Hair
Urine
Bone
Teeth
White blood cells
Spermatozoa and other cells
Cells in lining
Cells that line the mouth
Nucleated skin cells
Roots with attached cells
Cells shed in the liquid
Where We Also Find DNA
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Drink Containers
Food / Candy Wrappers
Toothpicks
Straws
Gloves
Cables / Cords
Jewelry Boxes
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Caps and Hats
Clothing
Cigarette Butts
Doors & Windows
Handled Tools
and Weapons
• Zip Ties and Rope
• Rocks
Laboratory Testing
• Laboratory Selection
▫ Determine which laboratory will be selected or agreed
upon for the analysis of the evidence
 Experience, accreditation, technology available, location
▫ Consider cost implications for private labs (analysis
and testimony)
 Federally funded assistance programs
▫ Consider resource implications for public labs
 Current workload issues and backlogs
▫ Determine if the analysis will need to be supervised or
monitored and by whom
▫ Weigh benefits and disadvantages of consuming
samples and, more importantly, who makes that call
Laboratory Testing
• Database “Technology”
▫ Determine if profiles can/should be uploaded to
CODIS
 Consider new NDIS upload rules for private lab sample
testing in July 2009
▫ Determine if profiles can/should be run against any
local or regional databases
▫ Limitations of DNA databases
 Qualifying samples in database
 Partial matching / familial searching considerations
▫ RFLP, DQ-a, Y-STR’s, and mt-DNA not compatible
with current DNA databases
Laboratory Testing
• Reporting and Notification
▫ Laboratory report distribution may
vary by local protocol or mandate
▫ Determine who will receive reports and/or
notifications on testing progress and results
▫ Determine when and how the information will be
shared with all interested parties
Effective Post-Conviction Testing
Some of the most important tools to a successful postconviction review process include:
Excellent coordination and communication amongst those
involved (prosecutor, defense attorney, and crime lab)
Well defined and articulated procedures or protocols for handling
post-conviction cases
Knowledgeable understanding of forensic science technology
or availability of experts to assist
The Power of Physical Evidence:
The Silent Witness
Wherever he steps, whatever he touches, whatever he leaves,
even unconsciously, will serve as a silent witness against
him. Not only his fingerprints, but his hair, the fibers from
his clothing, the glass he breaks, the tool mark he leaves, the
paint he scratches, the blood or semen he deposits or collects.
All of these and more bear mute witness against him. This is
evidence that does not forget… Only physical evidence is
infallible, and then only when it is properly recognized,
studied, and interpreted.
- Paul Kirk
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