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Footwear & Tire Track Examination - Coggle Diagram
Footwear & Tire Track Examination
General information
How is it done?
wich retailers/wich vehicles
suspect
identify type
footwear and tire track impressions = pattern evidence
Principles
3 main characteristics to analyze
Individual
from use
damage (some examples)
a cut
a crack
stone or twig stuck in the tread
Class
General class characteristics
= standard for every item
Limited characteristics
= unique
from manufacturing process
Wear
from natural erosion (caused by use)
examples
wear condition
the amount of depth of the wear
imprints and impressions
Why and When?
At almost any crime scene
Provides valuable information
Where?
Number of parties present
Direction?
Was on foot?
Connection to other crime scenes?
ex. of the most famous case involving shoeprints = 1995 O.J. Simpson murder trial
How it's Done
How Samples are Collected
Collecting entire object with prints/tracks
Lifting technique
adhesive lifter
= lifts the imprints from smooth, non-delicate surfaces
gelatine lifter
= a sheet of rubber with a low-adhesive gelatine layer on one side that can lift prints
Electrostatic dust-print lifting device
= tool that electrostatically charges particles to put the print on a lifting film
Casting
Photographs (@ 90° angle to produce true size)
Who Conducts the Analysis?
The Scientific Working Group on Shoeprints and Tire Tread Evidence (SWGTREAD) = makes standards for footwear/tire track examiners
people who did 550 hours of training
= a well-trained footwear and tire track examiner
Evidence that May be Examined
3 types of prints
plastic print
= a 3D impression left on a surface
ex. = shoe or tire tracks left in sand
latent print
= visible with powders, chemicles or alternate light sources
ex. = shoeprints detected on a tile
= created through static charges between the sole or tread and the surface
visible print
= visible with naked 👀
ex. = bloody shoe prints left on flooring
= a transfer of material from the shoe or tire to the surface
How and Where the Analysis is Performed
Tools and Techniques
ex. of tools = dividers, calipers, special lighting and low magnification
ex. of techniques = measuring the various elements, side by side comparasing, ...
Resources and References
database from the FBI
Evidence Submission and Examination
comparing evidence with suspects imprints
My own sources
https://www.youtube.com/watch?v=r6Io5hCy-VM
https://www.youtube.com/watch?v=3HcdX6d2pKc
https://theiai.org/footwear_and_tire_track_examin.php