Shoewear Impressions

Chapter 15 Cast and Impressions Students will be able to: : 

Forensic Science: Fundamentals & Investigations, Chapter 15 1 Chapter 15 Cast and Impressions Students will be able to: Distinguish between patent, latent, and plastic impressions. Describe how to make foot and shoe impressions. All Rights Reserved South-Western / Cengage Learning © 2012, 2009

Introduction : 

Forensic Science: Fundamentals & Investigations, Chapter 15 2 Introduction Patient impressions are two-dimensional Latent impressions are hidden to the eye Plastic impressions are three-dimensional People, vehicles, and objects leave evidence of their presence at an accident or crime scene.

Class Characteristics:: 

Class Characteristics: •Characteristics that repeat during the manufacturing process and are shared by one or more shoes. These include: size, design/pattern and mold characteristics. •Class characteristics reduce the number of shoes from every shoe in the world to a group of similar shoes. http://projects.nfstc.org/ipes/presentations/Gross_shoeprint-daubert.pdf 3

Individual Characteristics:: 

Individual Characteristics: •Unique, accidental, random damage on the outsole that is the result of its use and wear. •These nicks and scratches are in the outsole accidentally and in a completely random shape, orientation and position. http://projects.nfstc.org/ipes/presentations/Gross_shoeprint-daubert.pdf 4

Shoe Impressions : 

Forensic Science: Fundamentals & Investigations, Chapter 15 5 Shoe Impressions Shoeprint size indicates the foot size The depth of a foot or shoe impression indicates a person’s weight The type of shoe can tell something of the person’s job or personality Databases contain the names of specific manufactures and tread designs

Theory of Footwear Impression Evidence Examination and Identification: 

Theory of Footwear Impression Evidence Examination and Identification The unknown impression can be compared to the sole of a shoe, called the “known” The unknown impression can be compared to a test impression of the sole of a shoe called the “known test impression.” Given sufficient quantity and quality of the unknown impression, differences and similarities can be observed between the unknown impression and the known shoe and known shoe impression 6 http://projects.nfstc.org/ipes/presentations/Gross_shoeprint-daubert.pdf

Analysis: 

Analysis • Of the Known Footwear – Is the pattern/design similar or different from the crime scene impression? – Is there contamination in the outsole? – Is there any wear or accidental/random damage on the outsole? • Of the Test Impression made from the Known shoe – How are the characteristics in the outsole of the footwear represented in the test impression? – How do the characteristics in the outsole of the footwear repeat from one test impression to another? http://projects.nfstc.org/ipes/presentations/Gross_shoeprint-daubert.pdf 7

Shoe Wear Patterns : 

Forensic Science: Fundamentals & Investigations, Chapter 15 8 Shoe Wear Patterns Factors that personalize a person’s footwear: Body weight The way a person walks Weight distribution Direction of toes (straight, pointing out or in) The surface on which the person walks Unique holes, cuts, and debris embedded in the tread

Comparison: Side-by-side: 

Comparison: Side-by-side http://projects.nfstc.org/ipes/presentations/Gross_shoeprint-daubert.pdf 9 •Characteristics observed in the crime scene (unknown) impression are compared to the characteristics observed in the test impression of the known shoe. •Side-by-Side comparison •Superimposed comparison (overlay)

Lifting Latent Impressions : 

Forensic Science: Fundamentals & Investigations, Chapter 15 10 Lifting Latent Impressions Different methods to make latent prints visible: Luminol makes bloody footprints visible for photography Dusting the latent print reveals an impression for lifting or photography Electrostatic lifting and gel lifting (image below) techniques can capture hidden impressions

Preserving Impression Evidence: 

Preserving Impression Evidence http://www.sirchie.com/Assets/Cat_10_11/impressionEvidence7.pdf 11 Various methods of collecting impression evidence have evolved —now properly preserved impression evidence can provide a positive match to the shoes worn by the Perpetrator.

Steps to Casting Shoe Impressions: 

Steps to Casting Shoe Impressions http://www.sirchie.com/Assets/Cat_10_11/impressionEvidence7.pdf 12 STEP 1: Apply Dust and Dirt Hardener STEP 2: Pour water into zip-top bag, seal. STEP 3: Knead bag for 1-2 minutes . STEP 4: Pour into impression .

Preserving Impression Evidence: 

Preserving Impression Evidence http://www.sirchie.com/Assets/Cat_10_11/impressionEvidence7.pdf 13 Casting Shoe Impressions Shoe print found in mud Cast made from shoe print Suspect shoe matches Step 5 : Allow to Harden. Use the mold made from the cast to identify and match it to the shoe of the suspect.

Electrostatic Dusting and Lifting : 

Forensic Science: Fundamentals & Investigations, Chapter 15 14 Electrostatic Dusting and Lifting Electrostatic dusting reveals dust left with each step and creates an impression Electrostatic charges can lift impressions from Gel lifters also recover latent impressions paper carpeting wood surfaces linoleum asphalt concrete

The Electrostatic Dust Print Lifter: 

The Electrostatic Dust Print Lifter http://www.sirchie.com/Assets/Cat_10_11/impressionEvidence7.pdf 15 Locating and recovering obvious impressions from mud, dirt or blood are usually accomplished, but dust prints found in many indoor crime scenes are often overlooked and many times damaged or obliterated. By using the Electrostatic Dust Print Lifter, prints left in the dust of a floor, light soil from a criminals shoes, or impressions made on overlooked areas such as dusty walls or doors can be recovered.

Gel Lifters: 

Gel Lifters Forensic Science: Fundamentals & Investigations, Chapter 15 16 Gel Lifters consist of a thin film of sensitive gelatin on a backing sheet. Gel lifters are big sheets of gelatenous material with a sticky surface. The gelatin surface is excellent for picking up powdered latent prints, shoe impressions, etc. They can be used to lift shoeprints on concrete. The gel lifter is placed over the shoeprint, sticky-side down, and it will collect the shoe print when it is lifted up.

Collection of Shoe Impression Evidence : 

Forensic Science: Fundamentals & Investigations, Chapter 15 17 Collection of Shoe Impression Evidence Why would the following steps be important? Take photos as soon as possible Take multiple photos of the impression from at least two different orientations Place an identifying label and a ruler in position with the impression for the photo Use oblique lighting when possible