Footwear marks (or impressions) have the distinct potential to provide a conclusive association between the undersole of a particular shoe and a suspected footwear undersole mark recovered from a crime scene.
Examples of crime scenes where footwear mark evidence might be obtained include burglary & robbery scenes where footwear marks might be left on surfaces such as floors, tables, worktops etc, and also in murder / assault cases where footwear marks might be present on the victim, possibly in the form of bruising as a result of the assailant stamping on the victim, or footwear marks in blood in the vicinity of the scene.
In such crime scenes, these marks can be enhanced at the scene, photographed to scale and possibly “lifted” from the scene using gel lifts when the scene is being examined by crime scene investigators or similar.
If the mark is on a readily movable item such as a piece of paper, the item itself might be removed from the scene.
In addition, footwear marks might be on the clothing / body of an individual who has been the victim of a repeated kicking / stamping assault, in which case the marks, which could be in the form of bruising or blood might be photographed using lighting techniques to enhance its quality.
When a comparison is made between a suspect’s shoe and a crime scene mark, features of the undersole such as pattern, pattern configuration, size, degree of wear, and damage features are all assessed. In addition, the crime scene mark might show evidence of slight movement / slippage when the mark was made, or it might have been made when the undersole was wet, both of which can impose limits on the extent of the comparison.
There are literally thousands of different footwear undersole patterns, although some patterns can be very common, and in addition, some footwear sizes are very common, for example shoe sizes 8, 8½ and 9 together account for over 40% of men’s shoe sizes in the UK.
These factors generally mean that in the absence of damage or meaningful wear features to the undersole of a shoe or the crime scene mark, which might only be partial in nature, the strength of evidence to associate a particular shoe with a crime scene could potentially be somewhat limited.
However, small damage features on an undersole which are randomly created by the act of walking about in the footwear, if manifested in the crime scene mark, could potentially provide conclusive evidence of association simply because such features are entirley random in their creation, size, and relative positions on the undersole
In summary therefore, many factors have to be taken into account when assessing the strength of footwear evidence and in our experience it is vital that such evidence is independently assessed and evaluated. Indeed, in the past few years or so we have been involved in several cases where we have successfully demonstrated to the jury that the strength of footwear evidence was in our opinion overstated in cases which relied heavily on that evidence, and not guilty verdicts were returned.