Forensic Footwear Evidence Chapter 18 Forensic Footwear Evidence Page 341

What information can you gather from this foot?

What is Forensic Footwear Evidence? Physical contact between footwear and a viable surface leaves a transfer of class and individual characteristics, which can be used in identification of possible suspects P 361

Forms of Footwear Impressions =Those that remain after a shoe has permanently deformed a surface. =Those patent or latent prints left on a non-giving surface. Two Forms Three Dimensional Impressions Two Dimensional Impressions P 362

Forms of Footwear Impressions Note: Very often the less visible impressions actually retain greater detail than those that result from heavier deposits of residue, dust, or blood. Sand Mud Snow Three Dimensional Impressions Wood/Paper Glass Carpet Two Dimensional Impressions P 362

Information from Footwear Impressions 1 Positive ID of footwear 2 Elimination of Footwear 3 Location of Impressions and association with other evidence 4 Rebuttal or Confirmation of a suspect’s alibis 5 Determination of shoe brand/manufacturer --Proving a suspect’s presence at a crime and thus possible participation in the crime --Based o CLASS characteristics . . .. changes in or absence of random individual characteristics are normally not used to eliminate a shoe --Can help lead to uncovering other impressions or physical evidence --Aided by use of FBI footwear database that includes thousands of shoe designs P 362

Information from Footwear Impressions 6 Determination of shoe size 7 Gait characteristics 8 Linking of crime scenes 9 Number of perpetrators 10 Tracking --Recording dimen-sions of impressions can allow for general estimate of shoe size --Refers to how someone walks --Measurements from impressions include stride, step width, and walking pace --Note: not reliably used as a means of personal ID --Databases can store footwear impressions recovered from scenes and can be used to find a matches or links between different crimes (helpful with repetitive crimes like burglaries) -- More than one print design found can suggest the # of people who potentially committed the crime --Observing impression series that can result in following the path of an individual (ex illegal aliens and kidnapped children) P 362

Number of perpetrators? Tracking Determination of Shoe Size Association with Other Evidence Identification of Footwear ?

Video Duration~1:28

Location and Recovery of Footwear Impressions 1. CS Security: Important to secure crime scenes as soon as possible to prevent other impressions being tracked over the evidence 2. Location: Some impressions easily located (i.e. bloody or muddy) Most require more effort to locate Use alternative light source or electrostatic lifting device Use clues in environment as a place to look (i.e. entrance and exit points, and paper, magazines, or glass on floor which often hold latent prints in good detail) 3. Recovery next slide http://www.knoxandassociates.com/photo.php

Recovery (cont.) Starts with notes and photographs (# cards in photo) Take mobile prints to lab Prints that cannot be moved and may need to be enhanced. 1. Examination quality photography directly over print, 35 mm film, ruler in picture oblique/UV/infrared lighting for contrast possible use of chemicals to enhance before photo (ex. leuco crystal violet, amido 10 black, luminal) 2. Lifting 2-D prints Electrostatic—used for dry origin impression Fingerprint powder 3. Casting 3-D prints Use dental stone, a gypsum product Stronger than plasters and provided quicker and easier recovery P 365-66

Two – Dimensional Impressions Recovery (cont.) Two – Dimensional Impressions Once an impression has been photographed, the print may be able to be lifted Electrostatic lifting transfers Fingerprint powder in combination with mikrosil may be used on impressions where electrostatic lifting does not work Electrostatic Lifting Film This foil backed black mylar produces exceptional detail in even the most subtle dust impressions P 367

Electrostatic Lifting Device Text and image from: Introduction to Criminalistics: The Foundation of Forensic Science  By Barry A. J. Fisher, William J. Tilstone, Catherine Woytowicz

Three – Dimensional Impressions Recovery (cont.) Three – Dimensional Impressions Dental stone is primary means of casting footwear impressions On wet surfaces, a spray wax may have to be used first to seal impression Mix dental stone with water in a ziplock bag for 3 minutes Stone hardens in 20 minutes In 24-48 hours it will have fully hardened P 368 Pre-Measured Dental Stone

Enhancement Methods Poor impressions may have to be enhanced by one of the following means: NOTE: Enhancement similar to fingerprints Forensic Photography Oblique, ultraviolet, infrared lighting Physical Methods Latent powder, lifting impressions Chemical Methods Reagents such as leuco crystal violet, amido 10 black, or luminol Digital Methods Software such as Adobe Photoshop can be used to enhance impressions P 368

Recovered print Analysis: Need to have known shoes and exemplars to compare against Footwear from Suspected Persons: All footwear a suspect owns should be seized for comparison Shoes are needed to make test impressions P 370

Known Shoes and Preparation of Exemplars Known Test Impressions of Footwear- Examiner will make impressions of known footwear and compare them with suspected footwear impression to insure matching samples are highly detailed, and have individual characteristics of shoes Elimination Footwear – Footwear worn by police officers, medical personnel should be accounted for when considering impressions left at scene P 371

The Examination Process and Conclusions Areas of footwear which are examined by analyst include: Design of shoe Physical Size and Shape Wear marks Individual Identifying Characteristics- cuts tar, gum etc P 372

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