Examination of Firearms Review: 2007 to 2010 - Interpol

impression analysis. Biedermann and co-authors (47) discuss shortly the
implementation of this approach into shoeprint examinations, and deal with
feasible and defensible strategies for eliciting reasonable prior probabilities for
footwear marks compared to DNA stains analysis.
The range of conclusions, attributed to a given set of shoeprints, was presented by
Jonasson (48). In the course of the ENFSI EWGM 2 nd Collaborative Shoeprint
Test, participants were supplied with images of two footwear impressions, one on
floor tiles and the other – on a curtain, and images of a pair of relatively unused
tennis shoes and their test prints, and were asked to compare the prints with the
shoes images. The conclusions reached by the participating experts ranged from
elimination to identification, for the same given set of exhibits. This study
demonstrates again, as did previous ones, the subjective nature of footwear
impressions analysis. Based on the results of this test, a third one is being planned
for distribution this year.
2.6 Databases, Reference Collections and Automated Classification
With the numbers of both footwear outsole designs as well as shoeprints
documented at crime scenes rapidly increasing, the need for computerized mean
of keeping these records is becoming more and more crucial in forensic
laboratories. Bowen and Schneider (49) have published a review on various
commercially-available forensic databases, including those for shoeprints and tire
tread designs.
In addition to the ENFSI EWGM “Wanted Page” mentioned earlier, Hamm (50)
also presented the Foster & Freeman (UK) footwear and tire tread databases,
including the Crimeshoe.com program. This “pay-per-match” program (customers
only pay when a positive identification of the pattern in question have been found)
enables law enforcement agencies and forensic science laboratories to submit
queries regarding unknown outsole pattern, and receive a comprehensive report
when such a pattern is identified in the database.
The National Footwear Reference Collection (NFRC) has been launched recently
in the UK (51), as the result of collaboration between the National Policing
Improvement Agency (NPIA) and Bluestar Software Ltd. (UK), the latter having
designed and built the database of footwear patterns. This new, web-based
application service is hosted by the West Yorkshire Police on the secure Criminal
Justice Extranet (CJX) and is freely available to police forces. Basically, the NFRC
is a system for the identification of a particular footwear pattern using 14
nationally-agreed descriptors of the different elements making up the design of the
tread pattern. This allows police forces to identify footwear impressions recovered
from crime scenes rapidly and easily.
The potential of a spatial-temporal method for analysis of forensic shoeprint data,
collected at the Larger London Metropolitan Area (the Bigfoot database), was
examined by Lin et al (52). The large volume of shoeprint evidence recovered at
crime scenes (about 10,000 annually) was imported into a geographic information
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