Trace Evidence – Forensic Examination of Shoe Soles in a Criminal Investigation

Trace Evidence – Forensic Examination of Shoe Soles in a Criminal Investigation

It is imperative to understand the emergent, powerful, and widely effective technology that has been used in the investigation of crime scenes, and numerous cases have been solved by using various approaches. In this paper, the point of intrigue is the solving of the case involving a murder in which it is clear that a person riding a mountain bike on the side of a dirt country road was intentionally struck down by a suspect. The suspect then stepped out of their vehicle and shot the biker. A witness riding an ATV heard the shot and came on the scene just in time to see the suspect kick the victim hard a couple of times, presumably to determine if they were dead. Following this situation, as an investigator, I executed a warrant for the shoes of the driver/shooter and obtained the shoes worn by the suspect for examination. With this knowledge in mind, it suffices to say that this paper will attempt to provide the identity of several items from the soles of the shoes and provide an explanation of the conduction of the examination, the type of items I found, their possible significance to the crime scene, and how I would recover and package the evidence that we found.

Foremost, it is vital to point out that in this crime scene, the robust and rapid identification of the footwear of the suspect while he is in the custody of the police has proven to be a crucial component in a system that makes total use of the footwear marks gained from the scene of the crime (“Footwear & Tire Track Examination: How It’s Done,” 2021). It is also imperative to understand that footwear is a very vital forensic intelligence source and, at times, evidence. In this crime scene, we presented an automated system for the model identification of the shoe, which is from the outsole impressions that were directly taken from the suspect’s shoes that could offer information while the suspect is still in the custody of the police in a timely manner.

Also, the current process of identifying the shoe model from the 1000s of the recorded model kinds is a manual task that is quite time-consuming. In this case, the methodology is hinged on the broad numbers of the localized features found by using the MSER feature detectors (Pavlou & Allinson, 2009). As such, it is much slower and less efficacious. Some of the items found included the visible print, plastic print, and latent print. In this case, the visible print pertains to the transfer of material from the shoe to the surface of the crime scene. It is often visible by the naked eye, without necessarily having to use the additional aids. In this crime scene the assailant had left bloody shoe prints at this cordoned crime scene. When the investigation team looked at the crime scene, the visible prints matched those of the shoes.

Further, the presence of the latent print in this investigation crime scene is evident that it matches the shoes of the assailant. Latent print pertains to one that is not easily seen by the naked eye. Instead, it is developed through the static charges that are present between the tread or the sole and the surface. In this case, my team of investigators would use chemicals, powders, or an alternate source of light to locate the prints. Potent examples include the shoeprints found on the ground in this crime scene and the nearby dirt road.

In conducting this investigation, we used several methods to collect the footwear and the tire track evidence based on the impression type we found. For example, in this dirt road, we found impressions in the soil, and soft surfaces on the short grass around the scene of the crime. As such, we used the casting method whereby to create tire impressions as well as that of the footwear, we used this method that entailed the usage of the powdered stone material.

Furthermore, we used the dental stone, mixed it with water, and then poured in the impression and when it dried up, a three-dimensional impression model was created. Chemical stains and fingerprint powders or dyes were significant in bolstering the image color or further exacerbated the contrast against the background, enabling the casted evidence to be scanned and photographed. For the imprints we found, the investigation team made an effort to collect the jacket that had the imprint of the shoe on it. The imprint on the ground was lifted by one of the examiners, who used this technique to transfer this imprint to the medium that could be sent to the laboratory.

Also, it is essential to point out that the evidence we collected at this crime scene was properly documented, collected, and preserved to sustain this evidence’s integrity. The fact that impression evidence can easily get damaged, various steps were taken to prevent possible damage to this evidence, including securing and documenting the scene before collecting any evidence. For the impression evidence of the left shoe that we took, examiners used high-resolution images and chemical enhancers to capture as many details as humanly possible, more so with the latent imprints. We also ensured that photographing the impressions was vital because given that there is essentially a slight difference in diverse sizes of shoes, and the photographs failed to reach that ninety degree angle to this impression, then the actual size would not be produced to make a comparison of the real shoe. As such, the photographing investigators made sure that this aspect was addressed efficaciously to ensure that they matched each other.

Also, in this crime scene, there were shoe prints that could not be picked up, and as a result, our team of investigators used various lifting techniques to recover the evidence. The team used the Adhesive lifter bolstered by the fingerprint powders, whereby a heavy adhesive coating lifts the imprint from the smooth, non-delicate areas in the crime scene (Srihari, 2010). Its advantage over the adhesive lifter is that it can pick up a dusty shoe print on soft surfaces without tearing its surface. Besides, the team used the electrostatic dust-print lifting device because it electrostatically charges the particles within the dust or the light soil. Then they get attracted where they are bonded on a lifting film.

Moreover, the suspect’s shoes were submitted to the laboratory hand-in-hand with the collected evidence, where examiners used the shoes to make the test standards and a known source’s impressions that can be compared to the evidence collected using transparency overlays or the side-by-side comparisons. During the examination process, we used dividers, low magnification, special lighting, and calipers. In this case, we measured the diverse elements within the designs of the treads and the width and the length of the impressions and compared the measurements to what manifests in the impressions of the crime scene.

Using the low magnification and the special lighting, we aimed to determine whether various characteristics were accidental or whether it was something developed during the manufacturing process. Also, we performed side-by-side comparisons by placing the shoe alongside the scene of the crime print for the corresponding areas to be examined.

Lastly, in the packaging of evidence, the team made sure that only essential items were preserved. The examiners wore gloves to prevent contaminating the evidence, packaged each piece of evidence individually, and wrote identification on the exterior of these packages. Then they were placed in strong containers such as paper bags.

References

Footwear & Tire Track Examination: How It’s Done. Forensicsciencesimplified.org. (2021). http://www.forensicsciencesimplified.org/fwtt/how.html.

Pavlou, M., & Allinson, N. M. (2009). Automated encoding of footwear patterns for fast indexing. Image and Vision Computing, 27(4), 402-409.

Srihari, S. N. (2010). Analysis of Footwear Impression Evidence (Doctoral dissertation, PhD thesis, University at Buffalo).

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Forensic Examination of Shoe Soles in a Criminal Investigation

In this assignment, you will be exploring tasks that an actual crime scene investigator might accomplish.

There has been a murder in which it is clear that a person riding a mountain bike on the side of a dirt country road was intentionally struck down by a suspect. The suspect then stepped out of his or her vehicle and shot the biker.

A witness riding an ATV heard the shot and came to the scene just in time to see the suspect kick the victim hard a couple of times, presumably to determine if he or she was dead.

You have executed a warrant for the shoes of the driver/shooter and obtained the shoes worn by the suspect for examination.

Select a pair of shoes from your personal wardrobe, or borrow a pair from someone else. It is important that you select shoes that are at least 6 months old and are worn often (new shoes will not have much evidence on them. Using a household magnifying glass and a strong white light source—either a desk lamp or flashlight—closely examine the pair of shoes you selected.
Identify 3 or 4 items from the soles of the shoes, and explain in a 3–5-page paper how you conducted your examination, the type of items you found, their possible significance to the crime scene, and how you would recover and package the evidence you found.

Note: The following are just suggestions and are not mandatory for your paper grade. You may find this an instructive exercise.

You may have access to an ultraviolet light source like the ones used for identifying watermarks on money and checks commonly found at cashiers’ stations. Wear a pair of yellow glasses used as sporting glasses for skiing and shooting. This is just an extra suggestion and is not mandatory for the assignment.

You may also photograph items you have found and attach the photos to the paper if you care to. If you decide to photograph the items, do it on a piece of white bond paper—the photos will turn out better.