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the lower limb and spine to the person’s head. How the body deals with those forces, biomechanics, affects how an individual moves. Gait analysis is the detailed study of the positioning and movement of the way in which an individual walks through the various stages of the walking cycle. The movement of a person’s body is unique to each and this ‘signature’ of a person’s walk contributes to the forensic toolbox.


one is looking for. Analysis can then be performed for both the similar and dissimilar features of gait. Analysing the way people walk is very much a tool of identification.


The technique may also be useful in confirming the links between series of crimes – there have been a number of cases of this. Incident CCTV footage of the perpetrators was compared to the footage of suspects and it was determined that the same individuals were responsible for the chain of crimes.


Some perpetrators have tried to hide or


• Gait analysis can be used in a wide range of areas including: Identification of a person or persons at a crime scene


• Identification of a person pre or post-event • Identification of masked persons


• Verification of alibis by a person’s presence/absence at a location


• Comparing the effects of drugs/alcohol on gait


• Eliminating suspects • Locating and tracking persons of interest


• Providing information where other forms of ID are not suitable or available


• Reducing the time needed to analyse video • Suspicion to arrest


It may be a qualitative analysis or quantitative analysis that is carried out, or both, depending upon what video material is available. For example, a front view of an individual caught on CCTV could be compared to the front view footage of a known suspect and the angle of view can be important depending upon what


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disguise their walk, for example by wearing different clothing, but such efforts have often been unsuccessful. This is illustrated by a case where the cigarette being held by the perpetrator activated a security camera, with a thermal imaging sensor. Although it was poor quality video footage, it remained suitable for gait analysis. Even with the individual wearing baggy clothing, he could not hide the unusualness of his leg muscles and upper body posture.


There have been several cases of suspects admitting their guilt based on the forensic gait analysis evidence presented to them, resulting in considerable savings on investigation and court costs. What investigators need is a swift response, as to whether gait recognition can be useful or not in the identification process, whether it be to help prevent an incident, or post-event.


Moving forwards


Gait analysis has already been used in numerous cases and in different legal systems. It is possible to swiftly conduct analyses and gait comparisons and as technology becomes more routinely used, as it already is in some


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countries, it means that analysing electronic submissions can be very quick. When considering such cases as ‘The Night Stalker’ serial rapist case, the gait recognition used provides discernible benefits to public safety. In that matter there were over 200 offences, taking place over seventeen years. When the gait recognition analysis was utilised, it helped locate the perpetrator in a few months. Confirmation that early deployment of the gait analysis tool can significantly reduce the huge number of man- hours and associated costs by helping to find perpetrators.


With greater understanding of the deployment of gait recognition as a forensic tool, it is becoming a facility that is routinely used by security service providers and law enforcement agencies. As digital and real time footage become more ubiquitous and awareness increases that forensic gait analysis is often of use, where activity and offences are captured on CCTV, this will be of increasing assistance to investigations.


Gait recognition has repeatedly proven to be useful and will continue to be so, but the most valuable use could be in finding and recognising perpetrators, including at border and perimeter controls, before events occur. ‘The Night Stalker’ and many other cases have already proved what gait recognition brings to the table. In such uncertain times, we need to be alive to what works and has proved to be effective.


Haydn Kelly Consultant Podiatrist and Podiatric Surgeon. Dean of Podiatric Surgery


Examiner for the Faculty of Forensic and Legal Medicine at the Royal College of Physicians, London and a Fellow of the Faculty of Podiatric Medicine, Royal College of Physicians and Surgeons of Glasgow.


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