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Admissibility Resource Kit
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Foreword
The purpose of the Scientific Working Group for
Firearms and Toolmarks is to disseminate guidelines,
studies and other findings that may be of benefit to
the forensic community.
The following information is a collection of
information pertaining to the admissibility of
firearm and toolmark evidence. The material
presented here is the direct result of hard work,
research and dedication of many scientists and it is
posted here for you to read, evaluate and prepare
yourself when educating the criminal justice system
on this subject.
This collection of resources is not all-inclusive
but rather represents significant research, legal
opinions, challenges, rulings and other issues
related to the discipline.
Introduction
Admissibility standards being applied to forensic
science disciplines are creating new challenges for
the individual analysts when providing expert
witness testimony. The
analysts are being held to a higher standard in
justifying the science of their respective disciplines.
The Admissibility Resource Kit (ARK) is a repository
of pertinent information designed to primarily
assist Firearms and Toolmark Examiners in quickly
preparing for evidence admissibility hearings. The
information contained herein consists of general &
foundational text, listed documents, related
internet website links and visual aids that serve as
an effective educational tool. The layered or nested
formatting of this information will hopefully
provide a progressive learning vehicle that will
quickly educate the end-user on the critical
elements that should be mastered to articulate the
underlying scientific principles of the Firearms and
Toolmark Identification forensic discipline.
The SWGGUN
ARK is broken down into the
following categories,
Admissibility Rules Overview,
Foundational Overview of
Firearm/Toolmark Identification,
Review of
Admissibility Elements,
Court Rulings, Opposing and
Supportive Viewpoints of Firearm and Toolmark
Identification, and
Appendices.
When available, the actual articles will be provided
and can be accessed by clicking the title of the
article.
Admissibility Rules Overview
A
list of significant court decisions is provided here
that address the admissibility of expert scientific
evidence and testimony.
UNITED
STATES
Frye Test
A 1923 decision by the
District of Columbia Court of Appeals, known as the Frye
test, set a foundation for the admissibility of expert
scientific evidence. Under the Frye test, such expert
testimony was admissible only if the principles on which
it was based had been "generally accepted" by the
scientific community.
Rule
702-
Testimony by Experts
Notes
In 1973
(revised Dec. 1, 2003)
Federal Rules of Evidence,
Fed. R. Evid. 702, were adopted by the federal
courts system. This rule that broadly governed the
admissibility of expert testimony, didn’t mention
general acceptance, but stated:
"If scientific,
technical, or other specialized knowledge will assist
the trier of fact to understand the evidence or to
determine a fact in issue, a witness qualified as an
expert by knowledge, skill, experience, training, or
education, may testify thereto in the form of an opinion
or otherwise, if (1) the testimony is based upon
sufficient facts or data, (2) the testimony is the
product of reliable principles and methods, and (3) the
witness has applied the principles and methods reliably
to the facts of the case."
Daubert
Daubert refers to
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509
U.S. 579 (1993),
a case in which the court outlined criteria
which they believed could be important to
establish the reliability of expert testimony.
These criteria include the following:
- Has the
technique or theory been scientifically tested?
- Does the
technique or theory have a known or
potential error rate?
- Has the
technique or theory been
subjected to peer review and publication?
- Is the
technique or theory subject to standards
governing its application?
- Is the
technique or theory generally
accepted by the relevant scientific community?
Although these
criteria were not meant as a checklist, they are
being applied in this way. If one of these
criteria is not met, then the testimony may be found to be
inadmissible.
CANADA
Expert evidence
must be necessary in order to allow the fact
finder: (1) to appropriate the facts due to
their technical nature, or; (2) to for a correct
judgment on a matter if ordinary persons are
unlikely to do so without the assistance of
persons with special knowledge.
R. v. Mohan
[2 S.C.R. 9] 1994
Admission of
expert evidence depends on the application of
the following criteria:
- relevance;
- necessity
in assisting the trier of fact;
- the
absence of any exclusionary rule;
- a properly
qualified expert
R. v. D.D. [Supreme
Court of Canada]
2000
"The
application of the four Mohan
criteria is case-specific. Determinations
of relevance and necessity, as well as the
assessment of whether the prejudicial effect of
the evidence outweighs its probative value, must
be made within the factual context of the
trial."
Per Major J.,
46 "The second requirement of the Mohan
analysis exists to ensure that the dangers
associated with expert evidence are not lightly
tolerated. Mere relevance or "helpfulness"
is not enough. The evidence must also be
necessary."
"A fortiori,
a finding that some aspects of the evidence
"might reasonably have assisted the jury" is not
enough. As stated by Sopinka et al.,
expert evidence must be necessary in order to
allow the fact finder: (1) to appreciate the
facts due to their technical nature, or; (2) to
form a correct judgment on a matter if ordinary
persons are unlikely to do so without the
assistance of persons with special knowledge."
R. v. J.L.J.
[Supreme Court of Canada] 2000
The Supreme
Court expressly referenced Daubert as a relevant
authority [FN2-19 below] where the Supreme Court
expressly referenced Daubert as a relevant
authority and referred to many of the same
factors for analysis referenced by the Daubert
court. The Canadian law has now been made
clear by the Supreme Court.
International Admissibility Standards
No substantial standards for
Europe have been found to date.
Foundational Overview of Firearm/Toolmark Identification
Toolmark Identification is a discipline of forensic
science that is usually listed as Firearm and
Toolmark Identification because a firearm is
considered a specialized tool.
A toolmark examination
is an empirical comparative study that can
determine if a striated or impressed mark was produced
by a particular tool.
The basis for identification in Toolmark
Identification is founded on the principle
of uniqueness as described by Kirk through Tuthill;
wherein,
all objects are unique to themselves and thus can
be differentiated from one another. Additionally,
the underlying mechanism for the origination of
toolmarks is that when a harder object (the tool)
comes in contact with a softer object (work piece),
the harder object will impart its marks or
features on the softer object. This
mechanism for the origination of toolmarks is founded on
well-established principles derived from the
physical sciences that include physics, metallurgy, metallography and materials science, as well as many
mechanical properties presently used in mechanical
and industrial engineering.
The working edges of tools, that include components
of firearms that contact ammunition, generally
consist of some type of hard material, such as
steel, to ensure
strength and durability of the tool; while work
pieces are generally made of softer materials. These
surfaces of a tool that contact a material contain
random, microscopic irregularities that are produced
during the tool’s manufacture and/or subsequent wear
through use and abuse. These
irregularities which are formed randomly,
are
considered unique and can individualize or
distinguish one tool from another. Because
these irregularities or individual characteristics are typically
imparted onto the work piece, the comparative study
of the imparted markings allow the tool to be
individually associated or identified as having produced the mark.
The presence, observation and comparison of these
random toolmarks on tools form the hypothetical
propositions upon which the discipline of Toolmark
Identification is based.
The most widely accepted method used in
conducting a toolmark examination is a
side-by-side, microscopic comparison of
the markings on a questioned material item to
known source marks imparted by a tool.
The examination process used in Toolmark Identification is
similar to those used in the other comparative
disciplines in forensic science. This process begins
with a study of the most general characteristics
(class) of items to be compared, progressing through
(subclass) to the analysis and comparison to the
most specific characteristics (individual).
Any individual association or identification
conclusion effected through this examination process
results from the practical certainty based on the underlying (validated) scientific theory.
Review of the Admissibility Elements
A
good starting point for any examiner looking
for guidance in admissibility proceedings are the
two documents listed below.
, Grzybowski, R., Miller, J.,
Moran, B., Murdock, J., Nichols, R., Thompson, R., AFTE,
Vol. 35, #2, Spring 2003, pg 209-241
, Grzybowski, R.,
Murdock, J., AFTE, Vol. 30, #1, Winter 1998, pg
3-14
The
Five Prongs of Daubert
-
Testability of the Scientific Principle
Scientific
testing is a procedure for
critical evaluation of a scientific
methodology.
The methods applied to the
microscopic comparison of toolmarks have
been tested and re-tested over the course of
the discipline’s long history.
The following
link provides a list of works that have tested the
legitimacy of the methodologies used in
the field.
-
Known or
Potential Error Rate
Error rate is the frequency
at which one deviates from a correct
standard.
Errors can
occur through individual oversight or as a
result of the deviation from a particular
method. The forensic firearm and
toolmark community participates in
validity and proficiency testing from which
error rates can be calculated.
The following
link provides documents that outline the proficiency testing
program and published error rates.
-
Peer
Review and Publication
Peer review
is the evaluation of a
colleague's research.
Scientific
journals such as the Association of Firearm
and Tool Mark Examiners Journal, the Journal of Forensic Sciences,
Forensic Science International and others have peer review
processes that subject written works to
assigned reviewers for critique. If the work
is approved by the peer reviewer it is then
submitted for publication.
The following
published documents outline the peer review
processes for forensic journals that have
published firearms and toolmark related
articles.
Additional references will be added when
available.
, Denio,
Dominic J., AFTE Journal Spring 2002,
pg. 210-214
Journal of Forensic Sciences
Peer Review Process (pending)
Forensic
Science International Peer Review
Process (pending)
Canadian
Society of Forensic Science Peer Review
Process (pending)
International
Association of Identification Peer Review
Process
JFI Publishing Guidelines.pdf
Reviewer Guidelines Dec 2004.pdf
-
Maintenance of
Standards and Controls
The
establishment and maintenance of operational
guidelines for conducting analytical
testing.
Firearm and
Toolmark Identification has well-established
controls and procedures.
Representative documents that detail these
protocols include the AFTE
Technical Procedures Manual, AFTE Theory of
Identification, AFTE Glossary, AFTE
Training Manual, SWGGUN Guidelines, and
In-house Protocols. Additionally, the
following selected citations are references
that address issues in maintaining standards
of quality.
Guarding
Against Error, E. E. Hodge, AFTE, Vol.
20,No. 3, July 1988, pgs 290 – 293
Photo Documentation of Toolmark
Identifications – An Argument in Support,
Bruce Moran, AFTE, Vol. 35, #2, Spring 2003,
pg 174 -189
AFTE – Standardization of Comparison
Documentation Report– Adopted June 13,
2005, at AFTE 2005 Business Meeting,
Indianapolis, IN.
These controls
and procedures are continually subjected to
rigorous review by internal quality
assurance and external
accreditation/standardization bodies. Some
of these general accreditation and
standardization bodies are listed below.
Laboratory
Accreditation Bodies
Standardization Bodies
-
General
Acceptance in a Particular Scientific Community
General
acceptance is the approval by
a particular authoritative body of a technique or
methodology.
Firearm and Toolmark
Identification is well-grounded in the
scientific method and has been generally
accepted by the forensic science community
for decades. Firearm and toolmark
identification courses have been and
continue to be taught in forensic science
programs around the world. Funding of
scientific research in the area of firearm
and toolmark identification has been granted
to researchers outside the firearm and
toolmark community.
Grant
Programs
(Examples)
-
National Institute of Justice,
Washington, D.C.
-
AGIS, Brussels Belgium
-
Canadian Police Research Centre,
Ottawa Canada
Court Rulings
The
following is a list of some of the case citations
that relate to the admissibility of Firearm and
Toolmark Evidence in the United States and Canada.
While some of the issues expressed in these cases
regarding the qualifications of the individual
examiner and the application of the scientific
procedures may have merit, the scientific principles
and the basis for which opinions are expressed in
the field of Firearm and Toolmark Identification
remain well founded.
Supporting and Opposing Viewpoints to Firearm and Toolmark Identification
The
following link provides a list of articles from
legal, academic and other sources that have expressed
support or concerns
regarding the admissibility of Firearm and Toolmark
evidence.
Appendices
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