ACDLA “Loosening the Death Belt” Seminar January 2010 Joseph M. Saloom. CHALLENGING FORENSIC FIREARMS/TOOLMARKS EVIDENCE. Quick Outline. Basics of Firearms/ toolmarks examinations Possible sources of error Past defense strategies Daubert Science of firearms/ toolmarks identification
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ACDLA “Loosening the Death Belt” Seminar January 2010 Joseph M. Saloom CHALLENGING FORENSIC FIREARMS/TOOLMARKS EVIDENCE
Quick Outline • Basics of Firearms/toolmarks examinations • Possible sources of error • Past defense strategies • Daubert • Science of firearms/toolmarks identification • Examiner qualifications • Most effective strategies • Attacking the examiner’s qualifications • Get your own expert • Carefully review the evidence • Are there photographs? • Are there drawings? • Get all the notes and worksheets the courts will allow.
Fundamentals of Firearm & Toolmark Identification Definition: Toolmark Features imparted on an object by the contact and force exerted from a tool. • Two Types – • Impressed Toolmarks • Striated Toolmarks
Fundamentals of Firearm & Toolmark Identification Definition: Impressed Toolmark Features produced when a tool contacts an object with enough compressive force that it leaves an impression.
Fundamentals of Firearm & Toolmark Identification Definition: Striated Toolmark Features produced when a tool contacts an object with lateral force and motion.
Fundamentals of Firearm & Toolmark Identification The Science of Firearm & Toolmark Identification is based on two fundamental propositions:
Fundamentals of Firearm & Toolmark Identification Proposition #1 Toolmarks imparted to objects by different tools will rarely if ever display agreement sufficient to lead a qualified examiner to conclude the objects were marked by the same tool. That is, a qualified examiner will rarely if ever commit a false positive error (misidentification).
Fundamentals of Firearm & Toolmark Identification Proposition #2 Most manufacturing processes involve the transfer of rapidly changing or random marks onto work pieces such as barrel bores, breechfaces, firing pins, screwdriver blades, and the working surfaces of other common tools. This is caused principally by the phenomena of tool wear and chip formation, or by electrical/chemical erosion. Microscopic marks on tools may then continue to change from further wear, corrosion, or abuse.
Fundamentals of Firearm & Toolmark Identification Range of Conclusions • Identification • Inconclusive • Elimination
Fundamentals of Firearm & Toolmark Identification Range of Conclusions - Identification If the quality and character of the toolmark have sufficient detail, an identification can be concluded based on the correspondence of individual characteristics.
Fundamentals of Firearm & Toolmark Identification Examples of an Identification
Fundamentals of Firearm & Toolmark Identification Range of Conclusions - Inconclusive If the quality and character of the toolmark are lacking, an examiner may not be able to make an identification or elimination. In this case an inconclusive result would be the appropriate response.
Fundamentals of Firearm & Toolmark Identification Examples of an Inconclusive
Fundamentals of Firearm & Toolmark Identification Range of Conclusions - Elimination • If significant disagreement in class characteristics exists, an elimination conclusion would be the appropriate response. • If disagreement in individual characteristics of an exceptional nature exists, an elimination conclusion may be the appropriate response.
Fundamentals of Firearm & Toolmark Identification Examples of an Elimination
TRADITIONAL CHALLENGES • Daubert or challenge of the science • Examiner Qualifications • Bias of the examiner • Lack of documentation • Type of conclusion • Opposing Expert
Five Prongs of Daubert • Testability • General Acceptance • Peer Review • Known or Potential Error Rate • Maintenance of Standards & Controls
Daubert is a dead end Firearm & Toolmark Identification meets the reliability standard put forth by the Daubert decision because it : • is Testable • is Generally Accepted • is Peer Reviewed • has Known Error Rates • maintains Standards & Controls
Examiner Qualifications • How much experience does he/she have? • Where was the training received? • What type of supervision on the job? • Is the laboratory accredited? • Is the examiner certified?
Examiner Bias • Is the examiner an employee of the submitting agency? • Was there more than one firearm or tool submitted?
Laboratory Documentation • What type of notes were taken at the scene or to describe the evidence? • Were there photographs of the evidence taken? • If there was a microscopic match, were there photographs or sketches made? • Can they produce the documentation?
Type of Conclusion • Was the identification “to the exclusion of all others”? • Was the conclusion an indeterminate or inconclusive? • What was the conclusion based upon?
Hire an opposing expert • Most attorneys do not have a scientific background. • Most attorneys do not have a firearms identification background. • Most attorneys do not feel comfortable questioning the state’s expert. • Best solution is to hire your own. An opposing expert can assist in assessing the evidence.
Important Websites for Information. • www.swggun.org • Look for the Admissibility Resource Kit (ARK) • There are sites for admissibility rules, court rulings, elements, and opposing viewpoints. www.afte.org This is the Association of Firearms and Toolmarks Examiners web page.