Date post: | 04-Jan-2016 |
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Footwear Evidence
Objectives:
What is footwear evidence? How is it involved in crime scenes? How is it collected? How is it analyzed?
What is footwear evidence?
Different shoes will leave behind prints of different sizes and patterns.
Footwear Evidence
Three different types of shoe prints:
1. Three dimensional impression Shoeprint made in soft material (dirt, snow) Requires making a cast of the print Composition of dirt
or snow will determine the detail of the impression.
Footwear Evidence
2. Two dimensional print (visible) Dirt or other material picked up by shoe and
deposited onto flat, hard surface. Variety of surfaces
and materials deposited makes recovery of these prints complex.
Three different types of shoe prints:
Footwear Evidence
3. Two dimensional print (latent) Can leave behind barely visible dust Can leave impression in polish/wax/dust
Three different types of shoe prints:
Footwear Evidence
3. Two dimensional print (latent) Can leave behind barely visible dust Can leave impression in polish/wax/dust
Three different types of shoe prints:
Footwear Evidence
How are shoe prints evidence?
Most suspects wear shoes. Footprints are always left, it is whether
they can be located and differentiated from other prints.
Burglar
Shoes
Footwear Evidence
What information can shoe prints provide?
Link suspect or victim to scenes Link two crime scenes
Gait or Tracking information?
Footwear Evidence
Location of prints can: Lead to more evidence Refute alibis
Recovery of Footwear evidence
All shoeprints should be recovered from the scene as soon as possible (Transient evidence).
Scene should be controlled to prevent destruction of evidence.
Footwear Evidence > Collection
Recovery of Footwear evidence
Some prints can be visualized by darkening a room and using a bright light at a low angle.
Footprints should be documented: Location recorded and photographed
Footwear Evidence > Collection
Recovery of Footwear evidence
Objects with footprints should be removed if possible (paper, glass)
If can’t be removed, an examination quality photo should be taken.
Ruler: allows for enlargement to real size
Footwear Evidence > Collection
After photo, 2-D print can be lifted:
Electrostatic Lifting: A charge is used to lift dry
materials from surface to black film.
Lift provides more contrast Non-destructive Photographed for evidence
Footwear Evidence > Collection
After photo, 2-D print can be lifted:
Dusting: Fingerprint powder can visualize print Lifted with adhesive or gelatin Photographed for evidence
Footwear Evidence > Collection
3-D impression can be highlighted
Spraying with colored wax spray
Footwear Evidence > Collection
3-D impression should be cast
Cast picks up detail; is durable
Cast after photo Use dental stone
Footwear Evidence > Collection
Enhancement Methods
If footprint is made of blood, TMB or other color changing reagents can help visualize.
Footwear Evidence > Collection
Analysis of Footwear Evidence:
Class Characteristics can be used to eliminate a suspected shoe or suggest a shoe could have made the impression.
Size Pattern
Suspect shoe or test impressions compared.
Footwear Evidence > Analysis
Analysis of Footwear Evidence: Individual Characteristics can be used to
identify an exact shoe. However, these can change over time.
Footwear Evidence > Analysis