Examination of Firearms Review: 2007 to 2010 - Interpol

1. Introduction
The examinations of contact marks and related topics covered in this review are
among some of the core issues of forensic science. Although these types of
evidence may sometimes have the highest evidential values in definitely linking
suspects to scenes of crime, the techniques used are usually straightforward and
simple. This review covers advances in scientific methods applied to the forensic
examination of various marks, since the Interpol 15 th International Forensic
Science Symposium (IFSS) in October 2007 (1).
This paper is based mainly on a literature review, derived from the UK Forensic
Science Service (FSS) FORS database (Forensic Bibliography Database), which
covers articles published in the principle forensic science journals and other
relevant sources over the review period (2). This has been supplemented by a
search of the Internet for articles related to the forensic examination of marks,
using, for instance, the Google Scholar search engine (3). Manuals and standard
operating procedures of various forensic science laboratories, many of which are
relevant to this Review, may also be found on the Web, for instance – the Virginia
Department of Forensic Science (VA-DFS) ones (4). Since one of the purposes of
this Review is to provide a wide updated background for practitioners in these
fields, some publicly-available Internet references are also listed below.
2 Footwear and Tire-Tread Impressions
Footwear impressions may be considered, apparently, as one of the most
common types of evidence, and are found, virtually, in every scene of crime. As a
significant form of physical evidence, impressions left behind at the crime scene
may provide valuable information on where the crime occurred and the direction
the suspect travelled while committing the crime. This information may place the
suspect at the crime scene or eliminate him as having been there. A general
review of this field was published by Smith (5), covering both the class and
accidental characteristics found in shoeprints, and the evidential value of the
examinations’ outcome. Although general in nature, this article provides a good
starting point for novice in this area.
The Scientific Working Group on Shoeprint and Tire Tread Evidence
(SWGTREAD) continues its effort for setting professional guidelines for the
collection, preservation and examination of footwear and tire tread impression
evidence (6). The Group’s new Internet web-page provides a vast amount of
information, including some recently-approved guides:
• Guide for Casework Documentation (September 2008),
• Guide for the Chemical Enhancement of Bloody Footwear and Tire
Impression Evidence (September 2008),
• Terminology Used for Forensic Footwear and Tire Impression Evidence
(March 2009).
These guides, along with the previously-published ones, may be downloaded freeof-charge
from the SWGTREAD web-page. In addition, a “Daubert Resource Kit”,
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