Footwear Evidence Footwear Evidence What is footwear evidence

Footwear Evidence

Footwear Evidence What is footwear evidence? Different shoes will leave behind prints of different sizes and patterns.

Footwear Evidence Three different types of shoe prints: Three dimensional impression 1. § § § 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. Write bold

Footwear Evidence Write bold Three different types of shoe prints: Two dimensional print (visible) 2. § § 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.

Footwear Evidence Write bold Three different types of shoe prints: Two dimensional print (latent) 3. § § Can leave behind barely visible dust Can leave impression in polish/wax/dust

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 Write all What information can shoe prints provide? Link suspect or victim to scenes Link two crime scenes § § § Example: Richard Ramirez case Location of prints can: § § § Lead to more evidence Refute alibis Gait or Tracking information?

Footwear Evidence Gait pattern § Set of measurements of foot prints Examples § Stride length § Toe Angle – pigeon toed? § Weight Distribution – front or back § Directionality – degree of planning § Shoe Size – size of foot § Depth of impression - bodyweight Write all

Footwear Evidence > Collection Recovery of Footwear evidence § Due to numerous nuances, all shoeprints should be recovered from the scene. § Scene should be controlled to prevent destruction of evidence.

Write all Footwear Evidence Examples of different patterns Running – long stride length Carrying load – short stride length - dragging of feet Men have a longer stride length than women Men usually walk with toes out, women walk with toes in http: //science. marshall. edu/murraye/Footprint%20 Lab. html

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

Write all 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

Write bold 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

Write bold 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

Write all Footwear Evidence > Collection 3 -D impression can be highlighted Spraying with colored wax spray (snow)

Write bold Footwear Evidence > Collection 3 -D impression should be cast § § § Cast picks up detail; is durable Cast after photo Use dental stone

Write all Footwear Evidence > Collection Enhancement Methods If footprint is made of blood, TMB (tetramethylbenzidine) or other color changing reagents can help visualize.

Write all Footwear Evidence > 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 (make of shoe) Suspect shoe or test impressions compared.

Write all Footwear Evidence > Analysis of Footwear Evidence: § Individual Characteristics can be used to identify an exact shoe. § However, these can change over time (wear).

Sources • http: //science. marshall. edu/murraye/Footpri nt%20 Lab. html • www. centralia. edu/academics/forensicscience