Footprints are the chance prints left by the perpetrator at the crime scene. They are the impressions of the friction ridges found on the sole of the foot of human beings, that get imprinted on the surface on which the person has walked. The impressions formed are the result of Locard’s principle of exchange.
Footprints are unique to every individual just like fingerprints. There is a possibility in the case of fingerprints that the culprit may erase the fingerprints or have worn gloves so the fingerprints must not be available at the crime scene, but it is difficult to avoid footprints. To avoid footprints the culprit may wear footwear but then the footwear marks are obtained which are also of evidentiary value at the crime scene.
However, footwear marks evaluation is one of the methods involved in forensic examination, which involves techniques differing from the footprint examination techniques.
Formation of Footprints
Since footprints are similar to fingerprints, therefore their anatomy, formation, and types of occurrence at the crime scene are also similar. It is believed that they are also formed due to the friction ridges present on the sole of the foot.
Also, footprint science is based on the principle that no two persons have similar footprints. In other words, footprints are unique to individuals like fingerprints and can be considered as an example of the Law of Individuality.
The skin of the plantar portion of the feet and toes is different from the skin of the other body parts. The papillary ridges present on the plantar surface form a unique pattern that constitutes a footprint containing individual characteristics.
The friction ridges are formed at the fetal stage of every human individual and last till their lifetime. Therefore, they are one of the reliable physical evidence in forensic examination.
The footprints found at the crime scene may contain unique features along with ridge patterns. They can be phalange prints (formed by the phalanges and toes present at specific positions), crease marks (formed by the folds of the skin of the foot, which can be permanent or temporary), pits/corns/crack marks/deformity (these are not present in every individual), etc.
There is a unique condition related to feet in a few individuals (1.54% of the population) which is known as ‘flat foot’ where the complete instep region of the plantar surface of the foot is impressed on the surface. The curved area is not visible in such prints as in normal prints, which can be used as an identifying feature of an individual.
Examination of Footprints
The examination of footprints is conducted by the process of ACE-VR which is an acronym for Analysis, Comparison, Evaluation, Verification, and Report.
Analysis of footprints involves a thorough examination of the footprints which includes the study of the margins, lines, shapes, and position of various parts of the foot. There are a few methods that have been developed for the examination of footprints. They are:
- Gunn Method– In this method, lines are drawn from the rearmost point of the heel to the foremost points of each toe present in print. Also, a line is drawn across the most medial and lateral aspects of the ball of the footprint and observed.
- Optical Centre Method– Optical centers are marked on suitable points on the footprints and concentric circles are drawn around them. Lines are drawn between the optical centers of heels and toes.
- Overlay Method– In this method, the outline of the footprint is marked and positioned on an unknown impression. It is compared by matching the characteristics like crease marks, shapes of the toes and their positions, scats, etc.
The footprints are compared using the overlay method of analysis which will help in establishing a match between the unknown and known prints. The process will commence in the order-
Morphological analysis → placement of features → capturing the fine individual feature
The compared characteristics are then evaluated according to the standards which decide whether the known and unknown prints are produced by the same individual or different individuals.
The next step after the evaluation is the verification of different footprints which examiners conduct and then finally a report is submitted.
Footprints can elucidate the information about the link between the crime-victim-suspect, the age of an individual, the number of people present at the crime scene during the occurrence, the movement of the victim or suspect on the crime scene, etc.
Admissibility of Footprints in Court in India
In India, Section 51 of the Code of Criminal Procedure (CrPC) states that police can take the footwear of the suspect into custody to compare with the impressions found at the crime scene.
Section 5 of the Identification of Prisoners Act states that the magistrate has been given the power to direct any person to submit his footprints for the fulfillment of procedure in CrPC for further investigation. If any person refuses such orders, he will commit the offense under section 186 of the Indian Penal Code.
There is no provision for footprints in the Indian Evidence Act (IEA) and no power is granted to the court for trials. Section 73 of IEA only mentions fingerprints and not footprints. However, section 45 of IEA includes the opinion of the expert on footprints along with other impressions.
Though the footprints have potential evidential value, still they are not admissible as reliable evidence in court. They are considered corroborative evidence.
There have been many cases in India where the court stated that the conviction of the accused can not be based solely on the footprint evidence and the science of footprint analysis is not well established. The integrity of the footprint evidence, the collection procedure, and the analysis is always questioned, therefore it is not considered helpful evidence.
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