Forensic Footwear Evidence - The Naked Science Society

Foot & Footwear
Footwear Evidence
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
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
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
Two types of prints can be left:
Patent (visible)
Latent (invisible)
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
There are two forms of Footwear impressions;
Three-Dimensional Impressions
Two-Dimensional Impressions
Three-Dimensional Impressions are those that
remain after a shoe has permanently deformed a
Predominantly found on exterior surfaces such as
sand, soil, or snow
Can be shallow or very deep
Casting a 3-dimensional impression
Photography Paul Ricketts, 2006
Sports Shoes
Photography Paul Ricketts, 2006
Photography Paul Ricketts, 2006
Women’s shoes
Photography Paul Ricketts, 2006
3. The resulting quality and
impressions detail of a 3D
print depends on:
composition of the
substrate in which
the print was left
the amount of
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
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
#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
#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
#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
The measurement of a persons stride, step, and length can
Not a reliable means of identification
#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
Trackers are usually trained at the US border patrol
IV. Location and Recovery of Footwear
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
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
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
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
Once an impression has been photographed it can be lifted.
Electrostatic Lifting
Lifting improves the visibility and detail
Enables the removal of the impression to the lab
By passing a current of 10,000- 15,000 volts across footwear
evidence, you cause the particles that make up the evidence to
transfer to lifting film
Fingerprint powder in combination with mikrosil may be
used on impressions where electrostatic lifting does not
c. Lifting 3-D footwear prints
1. Dental stone is primary
means of casting footwear
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
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
Latent 2-dimensional impression: luminol
Photography Paul Ricketts, 2006
VI. Known Shoes and Preparation of
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
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
Other impressions
Casts can be taken of the impressions of
other objects. Eg, tyre tread
Tire Tread
Photography Paul Ricketts, 2006
Tire tread on ground
Photography Paul Ricketts, 2006