Introduction
As the crime rate increases all over the world, security experts also improve their crime risk management. The shoe impression is one of the ways of examining and locating evidence at a crime scene. The shoe print has helped to solve many crime incidences and the mysteries surrounding them.
During investigations, the concerned team members try to find any meaningful evidence that helps to find any persons that are responsible for the crime. Shoe impression is the collection of proof from the shoe marks left behind by the suspects (Canter, 2010). The impressions are important for court proceedings.
Types of Prints
One of them is visible print. It is the transfer of material from the shoe to the surface. Such marks are visible by the naked eye without any additional aids. For instance, there could be bloody shoe prints on the surface, on the body, or a piece of paper (Rose, 2008).
Another type is the plastic footprint. It is a three-dimensional impression left on a soft surface. It could the tracks of the shoe left in the sand, mud, or even snow. Lastly, there is a latent print. It is not easily visible to the naked eye. The print results from the static charges between the sole of the shoe and the surface (Rose, 2008). The examiners may have to use powder, chemicals, and even alternative light sources to discover such prints. Some of the examples include the footprints on a hard surface, tiles, window sills, or metal counters.
How to Collect Samples
When the footwear impressions are on the soil or snow, casting is the best method to collect the samples. For imprints, it is usually advisable to obtain the entire object that has the imprint. It could be a sheet of paper with the shoe print (Hails, 2012). Sometimes it is not possible to collect the evidence when it is on a large surface like a counter. The examiner may have to use the lifting technique to transfer the imprint to a medium that can be of use in the laboratory.
There is the need to have proper documentation just like any other evidence is essential for analysis. The collection and preservation methods should also preserve the integrity of the imprints. Since impression evidence is easily damaged, there is a need to secure and document the scene before collecting the evidence. It includes taking photographs of the site and the evidence impression (Hails, 2012).
There is usually a very slight difference between the shoe sizes. The photographer should ensure that he or she takes the photos at a 90° angle to the impression. The angle enables the photos to have the right size for valid comparison. It also helps to prevent wrong assumptions. It is also critical to preserve the high-resolution images of the imprints. The forensic experts should also use the alternate light sources or chemical enhancers to get all the needed details and even use the latent marks. Whatever method that the experts may use, they should be careful to collect the imprints as they are to prevent any distortions (Suboch, 2016).
The lifting techniques include the adhesive lifter. It involves the use of a wet coating of adhesive lifts. It mainly picks the imprints from the smooth surfaces such as tile or hardwood surfaces. It requires the use of the fingerprint powders. Another technique is the gelatin lifter. The method involves the lifting of prints from any surface using a sheet of rubber. It is more flexible than the sticky lifter. It can pick a dirty shoe print on surfaces.
Another method involves the use of an electrostatic dust print lifting device. It electrostatically charges in the light soil. It attracts the particles and bonds them to a lifting film. It collects dry and dusty residue impressions on most of the surfaces (Suboch, 2016). The casting method can obtain any foot imprints. Casting includes the use of the powdered stone material. It requires the mixing of the material with water and then pouring the mixture into the shoe impression. The result of the mixture is a three-dimensional image.
The experts can go further to get the very accurate impressions from the prints. A digital enhancement program such as the Adobe Photoshop can help to improve the quality of the photographed impressions (Gunn & Taylor, 2014). The fingerprint powder and chemical dyes can improve the color or increase the contrast against the background. It leads to the photographing of the lifted evidence with clear shots.
The Analysis Responsibility
The collection and analysis of shoe impressions require qualified expertise. Therefore, the experts are well-trained and experienced in shoe impressions. The professionals have gone through extensive training on the impressions, evidence detection, recovery, handling and examination procedures, laboratory and photography equipment and procedures (Canter, 2010). They have also learned about the courtroom testimony and legal issues, and casework. There is also a registered body to govern the work of the forensic experts. The Scientific Working Group on Shoe Print and Tire Tread Evidence has a published standard. It discusses the minimum qualifications and training for shoe imprints examiners.
Cases Reviews
In March 31st, 2010 a man had escaped the police because he was carrying 3½ pounds of marijuana. The Decatur Police detectives recorded a statement that indicated that they had seen the car involved in the crime on Illinois 48. The police detective Chad Larner told the Macon County Court that the car had exited from Interstate 72.
The police found the man four blocks away walking on Grand Avenue with muddy shoes that matched the imprints that had been at the place where he abandoned the car (Canter, 2010). He had abandoned on one of the streets. The shoe impressions were in the mud near the car. The experts took photographs of the impressions for further investigation.
Yeng Jun Wu, 45 was guilty for murdering the Shao Qing Chen in the 2013 case. The prosecutor, Patrick Bourke, had told the jury that the suspect had left a shoe print at the murder scene (Walker & Wood, 2010). It was the father who discovered his son’s body in his property. It had at least 40 cuts inflicted by a long sharp object. The police found a shoe box for a pair of shoes that resembled the imprints at the scene of crime.
Prada Australia shop company provided a sample pair of such shoes. A witness had confessed that he had shoes that were similar to those of Wu’s pair of Prada shoes. The police produced the shoe impressions from the murder scene that had similarities with the test impressions made of the Prada shoes. The primary evidence in this murder case was the pair of size 7 Prada men’s shoes (Walker & Wood, 2010).
Shoe impressions have helped to solve numerous crimes. Sometimes they have been the only crucial evidence the court and the police had to rely on to solve a crime. Forensic experts have had lengthy time conducting tests to discover the evidence.
References
Canter, D. (2010). Forensic psychology. Oxford: Oxford University Press.
Gunn, J. & Taylor, P. (2014). Forensic psychiatry. Boca Raton, FL: CRC Press/Taylor & Francis.
Hails, J. (2012). Criminal evidence. Belmont, CA: Wadsworth Cengage Learning.
Rose, M. (2008). Scene of the crime. New York, NY: Kingfisher.
Suboch, G. (2016). Real-World Crime Scene Investigation. Boca Raton, Florida: CRC Press.
Walker, P. & Wood, E. (2010). Forensic science experiments. New York, NY: Facts on File.