Footwear Impression Evidence

Detection, Recovery and Examination, SECOND EDITION

William J. Bodziak

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351447430
• Edition: 2
• Topic: Jura
• Subtopic: Forensik

Reviewed and recognized as the most authoritative source in the field, this book describes the methods used worldwide to recover and identify footwear impressions from the scene of a crime.

In this new edition, everything, including the original twelve chapters, bibliography, appendix, etc., has been clarified, updated and expanded. This edition includes updated and new information on recovery procedures and materials such as lifting, photography and casting; chemical enhancement; updated information about footwear manufacturing; footwear sizing; and known impression techniques and materials.

WHAT'S NEW IN THE SECOND EDITION:

Besides updating and expanding the twelve original chapters, Footwear Impression Evidence: Detection, Recovery and Examination, Second Edition adds three new chapters: one chapter on barefoot evidence, which concerns impressions made by the naked or sock-clad foot or those which remain in abandoned or discarded footwear; another new chapter on several cases in which the footwear impression evidence was of primary importance in bringing about a conviction or confession; and finally, a new chapter on the footwear impression evidence in the O.J. Simpson criminal and civil cases.

Awareness, Detection, and Treatment of Footwear Impression Evidence	1

Wherever he steps, whatever he touches, whatever he leaves even unconsciously, will serve as silent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool marks he leaves, the paint he scratches, the blood or semen he deposits or collects – all of these and more bear mute witness against him. This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It cannot perjure itself. It cannot be wholly absent. Only its interpretation can err. Only human failure to find it, study and understand it, can diminish its value.

Paul L. Kirk (deceased)

Crime Investigation, 2nd ed., J.I. Thornton, ed., 1974, p. 2.

General Information Regarding Footwear Impression Evidence Impression Evidence

Impression Evidence

Impression evidence can be generally defined as “objects or materials that have retained the characteristics of other objects or materials through direct physical contact.”

Many forms of impression evidence are encountered in forensic work, including fingerprints, palm prints, footwear impressions, tire impressions, bite marks, glove prints, bare footprints, socked foot impressions, firing pin impressions, lip impressions, ear impressions, contusion and abrasion pattern injuries, typewritten impressions, and rubber stamp impressions. Perhaps the oldest forms of impressions are plant and animal fossils, whose features were captured as they were impressed into layers of the surrounding rock and soil, now offering absolute proof of their existence.

Footwear Impressions: A Valuable Form of Physical Evidence

Crimes involve people and places. Persons committing a crime leave footwear impressions en route to, at, and exiting from the crime scene. As a form of physical evidence, footwear impressions provide an important link between the criminal and the place where the crime occurred. Yet, although footwear impressions are found at many crime scenes, the quantity found is far less than those which are actually present. They are located in only a small percentage of cases compared to that in which they likely exist. Failure to locate and recover this evidence is not forgivable, but there are some reasons that may explain why more is not found.

The location of footwear impression evidence, primarily on ground surfaces, makes it sometimes difficult or inconvenient to find, particularly if the impressions are latent or nearly invisible. Specialized lighting techniques are often required along with an aggressive effort to find the impressions. Many crime scene technicians have had little or no experience in searching for these types of impressions. In other instances, they simply may not have dedicated the time and effort needed to search for this evidence. In addition, the footwear impressions of the subject may be mixed with those of other persons, such as paramedics and investigators, who may have arrived at the scene ahead of the crime scene technician. The fact that there may be footwear impressions of others mixed with those of the suspect does not necessarily mean that the suspect’s were destroyed, yet many technicians are discouraged by such tracked over areas and mistakenly abandon any efforts to look for impressions.

Footwear impression evidence has also been frequently undervalued by investigators, attorneys, and the courts due to their limited knowledge of it. Investigators still occasionally ask the question, “What can you determine by comparing a footwear impression with a shoe?” And it is still not unheard of, in cases where a positive identification is made, to be asked, “Can you really say that shoe positively made that impression?”

The long-term effect of this limited knowledge and utilization of footwear evidence is often a further discouragement and deterrent for the crime scene officer to look for footwear impressions. Additionally, because footwear evidence often is latent or nearly invisible, the crime scene technician may erroneously feel that it is not present or, by not thoroughly looking, may even rationalize its believed non-existence. Information regarding this evidence should be implemented in any forensic training program or law enforcement training syllabus.

It is imperative that crime scene technicians and investigators be aware of the full importance of footwear impressions as physical evidence. When securing the crime scene area, they must preserve all forms of evidence, including footwear impressions. Before beginning the crime scene search, careful thought should be given to understanding what occurred at the crime scene, how footwear impression evidence would be relevant and could contribute to the proof of facts, and what areas of the crime scene might be the most logical to check first for footwear impressions. Then the footwear impressions should be aggressively and carefully looked for. What is not looked for will not be found!

Frequency of Footwear Impressions

Each time a person takes a step, their footwear is impressed against the ground and can cause a deformation of that substrate or result in the transfer of trace materials and residue from the shoe to the substrate. Because of the direct physical contact under the weight of the wearer, there is no doubt that some type of interaction between the shoe and the substrate occurs with each and every step. Although not all of the impressions will be visible or detectable, the chances are excellent that a great many of them will be.

If a crime occurred in an area where the ground was soft, such as a sandy beach or on a soft dirt road, no one would contest the common sense deduction that footwear impressions would be present. It would be simply impossible for the subject to step in those areas without leaving many impressions in the soft surface. If that same crime were to have taken place at another location with a different surface, one would not necessarily assume the presence of footwear impressions. However, the fact is the subject’s shoes would have impressed themselves against the ground’s surface just as many times, allowing an excellent chance that one or more of those impressions could be located and retrieved.

Today, everyone accepts the potential for the presence of latent fingerprints at a crime scene. Unfortunately, it is often not recognized that there is an equal and perhaps even greater chance that footwear impressions could be present as well. The average investigator could list many possible reasons why fingerprints would be left at a crime scene and their probable locations. The same investigators are not usually as knowledgeable about footwear impressions. Yet with every step that is taken, whether on soil, snow, concrete, a tile floor, carpeting, glass, a wooden window sill, a piece of paper, a bank counter, or on countless other objects and materials, a representation of the characteristics of the shoe sole can be impressed against and retained by that surface, in either a visible form, or in a latent form that can later be visualized.

For anyone who has not had the success of locating many footwear impressions at the scene of a crime and is not yet convinced that there are more footwear impressions present than those that are blatantly obvious, two examples are offered. A recent study conducted in several jurisdictions in Switzerland¹ disclosed that footwear impressions were located at approximately 35% of all crime scenes. The crimes investigated in those areas consisted primarily of burglaries. Communication from another fellow examiners reported that in the past three years, after re-emphasizing to crime scene personnel and teaching the basics of locating and recovering footwear impressions, the percentage of cases in which footwear impression evidence was now being submitted to their laboratory had increased from less than 5% to approximately 60%.²

Durability of Footwear Impressions

Footwear impressions are either permanent or can be permanently recorded. Footwear impressions at crime scenes are of sufficient durability to allow for their discovery, retrieval, recording, and examination. In fact, their durability and permanence in some cases is surprising.

Age of Impressions

The life expectancy of footwear impressions can range from a brief moment to years. There is often evidence or circumstances which allow the logical deduction of facts relating to the age of an impression. There is no way, however, to analyze a footwear impression and determine its precise age. Any deductions that involve age determination must be based on common sense and other factors known to exist in conjunction with the impression. Exterior impressions in snow, sand, and soil will begin to deteriorate after they are made. The speed and extent of that deterioration will depend on time, weather factors such as temperature, wind and rain, destruction by other shoes or tires, and the makeup of the substrate. Impressions in blood can last for years unless on exterior surfaces. Likewise, impressions in residue or dust will last for years unless the surface is cleaned or physically altered. Impressions on some surfaces that are routinely traveled over or cleaned will have a shorter life span. For instance, a footwear impression on a bank counter will be, in all likelihood, less than 24 hours old, since most bank counters are routinely cleaned and polished at least once every day.

Positive Identification of Footwear

In many instances, footwear impressions can be positively identified as having been made by a specific shoe to the exclusion of all other shoes. This identification is based on a physical match of random individual characteristics the shoe has acquired with those respective features in the impression. The identification is as strong as that of fingerprints, toolmarks, or typewritten impressions.

In other instances, the degree of detail retained in a footwear impression may not be sufficient to detect those random individual characteristics necessary to “positively” identify a specific shoe. However, the detail that is present may still be very significant. The combined size and design characteristics of the shoes alone, as explained in later chapters, are so numerous and diverse when diluted among the approximately 1.5 billion shoes sold annually in the U.S., that any specific size and design of shoe, without regard to wear or other characteristics, will be owned by only a very small fraction of 1% of the general population. Additional factors, such as manufacturing variations and wear, although not sufficient alone to enable positive identification, can significantly further reduce the number of other shoes that could have made the impression.

Information Provided by Footwear Impressions

Footwear impressions can reveal, in many cases, the type, make, description, and approximate or precise size of the footwear that made them. This information can often assist in the process of developing a suspect. In addition, the location of footwear impressions at the scene can often help in reconstruction of the crime. The presence, characteristics, and condition of the impressions may assist in determining the number of suspects, their path into, through, and away from the crime scene, their involvement in the crime, and the events that occurred during the crime.

Footwear impressions at crime scenes can also be used to corroborate or refute information provided by witnesses or suspects. As an example, in one homicide case, a person exited his residence in the snow and broke into his own house through a basement window. He was staging a false crime as an alibi to the murder of his wife, which he had just committed, and was claiming himself as a victim as well. The detective investigating the case noticed that the shoe prints in the snow exited the rear door and led to the basement window, an unlikely path based on the alibi and one that proved that person was lying.

In another case, the absence of any footwear impressions in the recently fallen snow-covered ground around a house implied that the crime was committed by someone in the house.

Gait Characteristics

Gait analysis is the systematic study of human walking. It is often helpful in the medical management of those diseases which affect the locomotor system. Normal human walking and running can be defined as “a method of locomotion involving the use of two legs, alternately, to provide both support and propulsion.”³

Terms are used to describe the placement of the feet on the ground. They include stride length, which is the linear distance between two successive steps of the same foot, and step length, which is the linear distance that one foot moves in front of the opposite one. The step length may be diffe...