Forensic Footwear Evidence Ch 18 Pgs

Terminology  Two-dimensional Impressions – Print that has length and width but no significant depth  Footwear databases – Computerized compilation of shoe sole designs for the purpose of associating a crime scene impression with a manufacturer or to link it to another crime scene  Electrostatic Lifting – Using a high voltage device to electrostatically transfer a dry-origin dust or residue impressions to a black film  Dry-Origin Impression – Impression that contains no significant moisture from itself or its substrate when made.

 Wet Origin - Impression containing significant moisture from the shoe sole or its substrate when made.  Dental Stone – gypsum product, similar to plaster of Paris. (Hard and durable)  Test Impressions – Impression made by using a known shoe or tire as a standard; used in the examination of shoe and tire impressions

I. Introduction 1. As persons walk about, their shoes track over hard surfaces acquiring :  Dust, dirt, residue, grease, blood, oils, paint, or moisture  Shoes then re-deposit these material back onto other surface as they track over it 2. Two types of prints can be left:  Patent (visible)  Latent (invisible) 3. Regardless of the type of surface, there is a transfer of both class and individual characteristics  These will help Forensic Scientist determine if a suspect’s footwear made the impression to a scene, or if it can be eliminated

4. The process includes:  The detection and recovery of the footwear evidence from the scene of the crime  Enhancing that evidence if appropriate  Producing known impressions of the shoes being examined  Comparing the crime scene impressions with the footwear

5. Footwear impressions are routinely used to prove a suspect was present at the crime scene.  Most frequently used in crimes were proof of the suspects presence is incriminating……homicides, burglaries, assaults, robberies, rapes,….

II. Forms of Footwear Impressions 1. There are two forms of Footwear impressions; 1. Three-Dimensional Impressions 2. Two-Dimensional Impressions 2. Three-Dimensional Impressions are those that remain after a shoe has permanently deformed a surface  Predominantly found on exterior surfaces such as sand, soil, or snow  Can be shallow or very deep

 3. The resulting quality and impressions detail of a 3- D print depends on:  composition of the substrate in which the print was left  the amount of moisture  presence of contaminants..sticks, stones, debris

Two-Dimensional Prints  4. Two-dimensional impressions are those made on non-giving surfaces, such as tile, linoleum, or wood flooring,  includes those made on paper, plastics, doors, carpet, clothing, broken glass, countertops,  a large number of both porous and non-porous surfaces can be stepped on or kicked by an item of footwear

5. 2-D impressions can be varied because the shoe may contain combinations of dust, dirt, soil, residues, grime, oils, or blood  Makes the methods of recovering harder 6. Some prints can be highly visible, others can be latent

 7. Regardless of the type of print, the examination results depend on the detail retained in the impression

III. Information from Footwear Impressions The following information may be obtained from footwear impressions: #1 Identification of Footwear  Prove suspect was at the crime scene #2 Elimination of Footwear  Based on differences in class characteristics

#3 Participation in the Crime  Can prove suspects presence at a crime scene #4 Location of Impressions  Can show point of entry/exit and insight to locations of other evidence #5 Rebuttal or Confirmation of Suspects Alibis  Prove suspects is lying or telling the truth

#6 Determination of Shoe Brand  Brand and description can be determined through a footwear database  #7 Linking Scenes of Crime  Useful in investigations of repetitive crimes #8 Determination of Shoe Size  If manufacture is known an accurate determination of size can be made

#9 Number of Perpetrators  The number of prints recovered can indicated whether a group of criminals or an individual committed the crime #10 Association with Other Evidence  Backtracking can help locate other evidence #11 Gait Characteristics  Gait analysis us primarily use for persons with a walking problem  The measurement of a persons stride, step, and length can change  Not a reliable means of identification  ionid%3D67C779B3C46FD887ACA64FD97A20FA65%3Fcontentid%3DAclSc0XnIeGS2JX7dr81sW61&h=165&w=210&sz=17&hl=en&start=5&usg=__Wkqxpo4 RWQYgkgg1cII2iYdsRtA=&tbnid=YemSlO11jdmS0M:&tbnh=83&tbnw=106&prev=/images%3Fq%3Dforensic%2Bgait%2Banalysis%26gbv%3D2%26hl%3Den%26saf e%3Dstrict%26client%3Ddell-usuk%26channel%3Dus%26ad%3Dw5 ionid%3D67C779B3C46FD887ACA64FD97A20FA65%3Fcontentid%3DAclSc0XnIeGS2JX7dr81sW61&h=165&w=210&sz=17&hl=en&start=5&usg=__Wkqxpo4 RWQYgkgg1cII2iYdsRtA=&tbnid=YemSlO11jdmS0M:&tbnh=83&tbnw=106&prev=/images%3Fq%3Dforensic%2Bgait%2Banalysis%26gbv%3D2%26hl%3Den%26saf e%3Dstrict%26client%3Ddell-usuk%26channel%3Dus%26ad%3Dw5

 #12 Tracking  Tracking involves following the path of an individual by observing evidence that the person has created as he/she passes over various surfaces  Includes shoeprints, footprints, crushed debris, displaced rocks, sticks or leaves that may have been stepped on  Most commonly used for tacking illegal aliens and missing children  Trackers are usually trained at the US border patrol

IV. Location and Recovery of Footwear Impressions 1. It is critical that proper techniques be used to locate, document and recover footwear evidence  Otherwise its evidentiary value is lost 2. Success in locating the shoeprint and recovering maximum detail from each impression has a direct impact of the usefulness of the evidence. 3. Impressions may be full or partial.  Partial prints may only be a small percentage  It may contain enough detail to be identified or eliminated

4. An impressions value will not be known until it is fully recovered, enhanced, examined, and compared with shoes.

5. Most impressions are found on floor surfaces  Critical that the scene is secured 6. Some impressions are obvious (bloody prints next to a victim), others will require a more deliberate effort to locate.

a. Locating impressions 7. Methods of locating an impression: i. slow visual search, followed by darkening the room and using a high-intensity oblique lighting source

ii. Application of an electrostatic lifting device

iii. Closely examine any items that may have been stepped on Paper items usually contain high amounts of latent dust, broken glass usually contain high amounts of detail, but needs a special lighting source iv. Exterior surfaces, especially near logical entry/exit points

8. Crime scene notes should provide the location, direction, and description of prints. 9. Notes should coincide with photographs to help reconstruct the sequence of events.

 10. Any impression at a crime scene that can be safely recovered should be taken to the lab.  Examination photographs are used for prints that cannot be recovered

b. Lifting 2-D footwear prints 1. Once an impression has been photographed it can be lifted.  Lifting improves the visibility and detail  Enables the removal of the impression to the lab 2. Electrostatic Lifting  By passing a current of 10, ,000 volts across footwear evidence, you cause the particles that make up the evidence to transfer to lifting film 3. Fingerprint powder in combination with mikrosil may be used on impressions where electrostatic lifting does not work

c. Lifting 3-D footwear prints 1. 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 hours it will have fully hardened

V. Enhancement Methods 1. Poor impressions may have to be enhanced by one of the following means:  Forensic Photography – oblique, ultraviolet, infrared or other special methods  Physical Methods – latent powder, lifting impressions, or impressions on paper  Chemical Methods – reagents such as leuco crystal violet, amido 10 black, luminol or fuschin acid may be used to enhance bloody prints  Digital Methods – Software such as Adobe Photoshop can be used to enhance impressions

(LCV) leuco crystal violet

diaminobenzidine

VI. Known Shoes and Preparation of Exemplars 1. Footwear from Suspected Persons:  All footwear a suspect owns should be seized for comparison  Shoes are needed to make test impressions 2. Elimination Footwear  Footwear worn by police officers, medical personnel should be accounted for when considering impressions left at scene 3. 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

VII. The Examination Process and Conclusions 1. 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