Personal Identification – Anthropology by K.V RAMESH

Introduction

Personal identification is defined as the determination of the individuality of a person. It also refers to the process of linking an unknown personal object or material (which may be a whole body, a skeleton, a finger print, a biological fluid, etc.) back to an individual of known identity (Christensen et al, 2013). It is a key issue in forensic anthropology and consists of the correct assignment of an identity to an unknown corpse. Although it may seem an easy and automatic procedure, the mechanism of identification encompasses several difficulties concerning the methods, and above all, the significance of identification process in court. The process of identification is towards two conclusions: exclusion and positive identification.

Complete and Partial Identification

Personal Identification may be complete (absolute) and incomplete (partial): Complete identification is the absolute fixation or exact specification of the individuality of a person along with the determination of exact place in the community occupied by him. Partial identification refers to the ascertainment of only some facts about the identity while others remain still unknown. Partial identification may assist in complete or total identification of a person. e.g. identified as a female, Christian, about 40 years of age, having 6 feet height, whereabout regarding her family, occupation etc. are not known.

Need of Personal Identification

In medico legal cases identification is very crucial in living as well as in dead.

1. In Living:

Civil Cases : (a) In impersonation or false personification cases in relation with (Inheritance of property , Pension , Life insurance, Voting rights, Passport ) (b) Disputed identity in cases of divorce or nullity of marriage : (c) Disputed Sex (d) Missing persons (e) Lost memory patients
Criminal Cases : Identification of accused in criminal cases of assault, murder, dacoity, sexual offenses , Absconding soldiers , · Interchange of new born babies in hospital , Criminal abortion , To fix up age of criminal responsibility and majority , Impersonation in criminal cases (Bardale, 2011)

2. In Dead:

The need to identify the dead is obvious for social and medico-legal purposes. It is required in cases of natural mass disasters like earth quakes, tsunamis, landslides, floods etc., and in man-made disasters like bomb explosions, fire, air crash, building collapse, railway accidents or bodies recovered from sea, rivers, canals, wells and in cases when the body is highly decomposed or dismembered to deliberately conceal the identity of the individual (Modi, 2011).

Medico legal Aspects of Identity

Identification of living is usually carried out by the police. However, where medical knowledge is required for elucidation of disputed facts, a medical examiner may be consulted. A medical person is mainly concerned with the identification of dead bodies. Accurate identification is mandatory for the establishment of corpus Delicti after homicide since unclaimed bodies, portions of dead body or bones are sometimes brought to the doctor to support a false charge.
The term ‘Corpus Delicti’ means the body of offence or the body of crime. In a charge of homicide it includes:

(a) Positive identification of the dead body (victim) and
(b) Proof of its death by criminal act of the accused.

Experts who are involved in personal identification may include: pathologists, physicians, dentists, anatomists, physical anthropologists, and experts in evaluation of various traces . The interest of the community in the scene of death, after the discovery of remains or after a mass disaster, is often overwhelming. The disturbance of scene by curiosity seekers or by ill-trained police personnel may preclude not only accurate identification of bodies but also complete collection of physical evidence. This invites the “Law of Multiplicity of Evidences’ to play its role wherever called for. The Supreme Court has laid down that in law, a conviction, for an offence does not necessarily depend upon the ‘Corpus Delicti’ being proved. The cases may be conceivable where the discovery of the dead body, from the very nature of the case, is impossible. Therefore, it may be said that the existence of the dead body of the victim is no doubt a proof positive of death but its absence not fatal to the trial of the accused for the homicide. Indeed, any other view would place in the hands of the accused an incentive to destroy the body after committing murder and thus secure immunity for his crime (Vij, 2008).

The examination of a person for the purpose of identification should not be undertaken without obtaining his free consent, and at the same time it should be explained to him that the facts noted might go in evidence against him. It should be remembered that consent given before the police is of no account, and that the law does not oblige anyone to submit to examination against his will and thus furnish evidence against himself (Modi, 1977).

Bertillon system of Identification

“Every measurement slowly reveals the workings of the criminal. Careful observation and patience will reveal the truth.”
Alphonse Bertillon in 1879 (French criminologist) first developed the anthropometric system of physical measurements of body parts, especially components of the head and face, to produce a detailed description of an individual. This system also known as the Bertillon system, or bertillonage, is widely used as a reliable, scientific method of criminal investigation. The following physical measurements and data were included in this system:

Descriptive Data: Colour of eyes, hair, complexion, shape of nose, ear and chin.
Body measurements: Height, head length, head breadth, arm span, sitting height, left middle finger length, left little finger length, left foot length, right ear length, cheek width and cubit.
Body marks: moles, scars and tattoo marks
Photographs: front view and right profile of the head

These measurements, along with photographs, were recorded on cardboard forms which were kept in a specially arranged cabinet. By dividing each of the measurements into small, medium and large groupings, Bertillon could place the dimensions of any single person into one of 243 distinct categories. This system requires the employment of special instruments and a large number of men, so that there is always a possibility of errors creeping into the records of the actual measurements.

However, this system had serious drawbacks. It was limited to adults, and there was often a marked difference in the measurement of a person who had been measured in different police departments or for a second time in the same department.

Early Genetic testing for Human Identification – Antigens on red blood cells can be used to help identify an individual. Antigens themselves are not alleles, but are the result of what allele is encoded by a person’s DNA. The six different major blood group systems that have been used for human identification are ABO, Rh, MNS, Kell, Duffy and Kidd. Discovery of the ABO system and that each blood group is derived from a genetic locus was the beginning of genetic testing for human identification.

Identification in the Living

Identification in the living persons is justified for various reasons. Identification of living almost exclusively depended on recognition by personal impressions until the fingerprint was recognized as a powerful means of identification. It is still being employed as part of the investigation of crime to hold ‘identification parades’. The suspect or the accused is included in a group of persons of approximately similar build, age and appearance etc. and witness/witnesses are invited to point out one of them as the alleged criminal.

The identification of the living person is based entirely on known finger prints or birth marks or several personal impressions with regard to characteristic gestures, movements or shape and other features of the teeth, eyes and hair, or voice but is liable to mistakes. These methods require the services of different experts with reasonable experiences. Fingerprints, palm prints and toe prints are unique, as means of identification, both in living as well as in dead. Along with these other characteristics may be included like testing of mental calibre, educational level in the living which, for obvious reasons cannot be applied to the dead.
Photography is also an important aid in identification of living but may be of not much use in the identification of dead. Appreciable change, exaggerated by decomposition can occur in features after death. However, it may also be wrong to assume that excellent photographs never lead to an error in the identification of living.

Identification of the Dead

The identification of dead body sometimes becomes very difficult owing to its rapid decomposition in the hot season, or through damage caused by wild animals when exposed, on the outskirts of a city or village. The problem of identifying a recently dead person whose features, clothes, fingers are intact is totally different from identifying the same person, dying in the same fashion but whose naked body is discovered in a field and that too in the peak of summer/rainy season. The longer the interval between death and examination of the body/remains, the greater the need for varying experts in establishing the identification. Under such situations, sight recognition of the body for positive identification must be accepted with a caution and the investigator should never relax his/ her vigilance. The examination of a person for the purpose of identification depends on the presence of the following data or techniques. These are as follows:

1. Primary Characteristics: Age, Sex, Stature. These characteristics cannot be altered after death
2. Secondary Characteristics: Features, personal belongings (pocket contents, clothes including any marks /defects / stitching, jewellery etc.), Hairs, Scars, Tattoos, External peculiarities including deformities, whether natural or due to disease, occupational stigma, Race, religion and nationality.
3. Comparative data/techniques: Dental patterns or restorations, fingerprints, footprints or handprints, superimposition technique, neutron activation analysis, Anthropometry, trace evidence comparisons and other fortuitous comparisons (Vij, 2008).

The following Information is usually noted for the purpose of identification:

1. Race: Race is a population concept, which differs in the frequency of genes. There are three main types of races: Caucasoid, Mongoloid and Negroid. The particular race of a person can be determined on the basis of skull, forehead, skin colour, hair form, facial form and eye form.
2. Sex: It is easy to determine sex in normal cases from external appearance and inspection of genitals, but it becomes difficult in case of intersex, concealed sex, advanced decomposed body and in the skeleton. Sex of a person can be determined by any one of the following: Physical morphology ; Bone Study ; Microscopic study of sex chromatin in cells ; Gonadal biopsy ; Hormonal study (in case of intersex) ; Dental methods
3. Age: Age of a person can be determined by following methods: Physical or morphological features ; Some laboratory tests (in infants) ; Age estimation by teeth ; Age estimation by ossification activities & growth of bone ;
4. Complexion and features: The complexion may be fair, whitish, coloured, dark, brown or shallow. The colour may vary in different environmental conditions. The facial features include eyes, nose, lips, chin, ear and teeth. These features may change considerably from disease, dissipation, ageing or due to stress.
5. Hair: This forms an important means of identification, as it resists putrefaction and the effect of dyeing, bleaching, cutting or heat can be noticed. Examination of hair (form, colour, texture) is also of considerable help in crime detection as it is frequently found at the scene of crime.
6. Anthropometry and Dactylography: Anthropometric system is widely used for personal identification. It deals with the measurements of various parts of the human body. It is also called Bertillon system (Bertillonage) introduced in 1882. It is based on the principle that after twenty-one years of age no change occurs in measurement of various parts of body. Therefore, this system is applicable to adults only. Dactylography, also known as fingerprint system and consists of taking the impressions of the bulbs of the fingers and thumbs on an unglazed white paper and examining with magnifying lens. It is based on the principle that skin of the balls of the fingers and thumbs is covered with particular ridges, the arrangement and distribution of which remains constant throughout life.
7. Footprints: Footprints are impressions of foot or footwear left behind by a person walking or running. The careful observation of a footprint reveals many interesting facts regarding his/her mode of walking or running and may be as specific as a finger print.
8. Deformities: Deformities are good source of identification both in dead and living. It may be congenital or acquired. Congenital deformities include cleft-palate, harelip, super-numerary fingers or toes, supplementary mammary, web-fingers or toes, birth marks and moles whereas acquired deformities are malunited and ununited fractures of the bones of extremities.
9. Scars: A scar or a cicatrix is a fibrous tissue covered by epithelium formed as a result of the healing process of a wound or injury in which there has been a breach of continuity of substance. They may be linear, broad, circular, and irregular depending on the original wound. They can also help in finding out the cause of injury. E.g. wound of a shot.
10. Tattoo Marks: Tattoo marks provide wide information about the person possessing them. Their designs vary from initials to Gods of worship and even those indicating emblems of moral depravity art. They can be permanent or temporary. Sometimes tattoo marks may be superimposed over the old ones to obscure the identity.
11. Occupation Marks: Occupational marks are helpful in identifying a person as certain occupational work leave marks on hand/feet by which individuals involved in them may be identified e.g. horny and rough hands are noticed among the persons who do hard manual labour.
12. Handwriting: Handwriting is another good source of identification, especially in case of questioned or altered documents. Alterations in handwriting can be noticed in case of mental and nervous disease, tremors, and rheumatic diseases of joints of hand. Different patterns of handwriting are also noticeable in case of variations in nationality, occupations and ethnicities.
13. Clothes and Personal Article: Clothes and ornaments can provide a valuable source of identification in case of mass disaster. In living persons, clothes and personal articles do not form any essential piece of evidence for identification as the individuals can change them at will.
14. Speech and Voice: Peculiarities of speech e.g. stammering, stuttering, lisping and nasal twang assist in the process of identification. Voice is also affected in nervous diseases, such as cerebrovascular episodes, general paralysis of the insane and disseminated sclerosis.
15. Gait: An individual can also be recognized from his gait or body contour but it may be altered by an accident or disease such as locomotor, hemiplegia, spastic paraplegia.
16. Tricks of manner and habit: This form of identification is generally hereditary e.g. repetitive jerky movement of the shoulder or muscle of the face.
17. Mental Power, Memory and education: Identification based on these points are also helpful in establishing the identity of person especially in case of imposture.
18. Miscellaneous Methods of Identification: Electrocardiogram or vectocardiogram may be useful in the identification of individuals as no two cardiograms are alike. DNA fingerprinting and lip prints are other modern methods of identification.

Recent trends in Personal Identification

Physical Biometrics:

A biometric which recognizes an individual on the basis of his physical characteristics is referred as physical biometric. Examples of physical biometrics include face, fingerprint, hand geometry, palm print, iris and DNA. A brief introduction to these biometrics is given below:

Face: Facial appearance is used as a primary means for recognizing humans. Face recognition is the most acceptable tool of biometrics because of its non-intrusive method and naturalness. The most popular approaches to face recognition (Stan and Jain, 2005)are based on either (i) the location and shape of facial attribute, such as eye, eyebrows, nose, lips, chin, and their spatial relationships, or (ii) the overall (global) analysis of the face image that represents a face as a weighted combination of a number of canonical faces. In order for a facial recognition system to work properly, it should automatically (i) detect whether a face is present in the acquired image (ii) locate the face, if it is present; and (iii) identification of the face from a general viewpoint (i.e. from any pose) under different lighting conditions. The face recognition system is also influenced by variations in facial expressions.
Fingerprint: Fingerprinting has a long history as an important tool of biometrics. A fingerprint is the pattern of friction ridges and valleys on the surface of a fingertip. The formation of fingerprint is determined during first seven months of foetal development. Each individual has a unique pattern of fingerprint. Even the identical twins do not have the similar pattern of finger prints. The types of information that can be collected from a fingerprint friction ridge impression include the flow of the friction ridges, the presence and the absence of features along the individual friction ridge path and their sequence, and the intricate detail of a single ridge. The process of fingerprint feature extraction typically starts by examining the quality of the input image. Multiple fingerprints of a person (e.g. ten digits used in integrated automatic fingerprint identification system) provide additional information to allow for large scale identification involving multiple of identities. The process of fingerprint feature extraction typically starts by examining the quality of the input image. The local ridge orientation is then used to tune and filter parameters for image enhancement and ridge segmentation. From the segmented ridges, a thinned image is compared to locate the minima features. The machine representation of a fingerprint is critical to the success of the matching algorithm (Bolle et al., 2004).
Hand Geometry: Hand geometric biometric system consists of a number of measurements taken from the human hand, including its shape, size of palm, and the lengths and widths of the fingers. This technique is simple, easy to use and inexpensive. The authentication accuracy of hand geometry is not influenced by the environmental factors such as dry weather but show variations during the growth period of children. In addition, an individual’s jewellery (e.g. rings), or limitations in dexterity (e.g. from arthritis), may pose challenges in extracting the correct hand geometry information. The size of hand geometry biometric is large and it cannot be embedded in small screen devices. A number of other authentication system is also available that are based on the measurements of a few fingers such as index and middle finger. These devices are smaller than the hand geometry devices and are easy to use.
Palm prints: The palms of the human hands also contain unique pattern of valley and ridges. The area of palm is much larger than the area of a finger, and as a result, palmprints are expected to be even more distinctive than fingerprints (Zhang et al., 2003). Palms of the human hands consists of many unique features that can be used for personal identification such as principle lines, wrinkles, ridges, minutiae points, singular points and texture. These features can be extracted at different image resolutions. For civil and commercial applications, low resolution palm print devices are more suitable due to their small size and shorter computation time.
· Iris: Iris texture is a unique and reliable biometric trait for personal identification. The iris is the annular region of the eye bounded by the pupil and sclera (white part of the eye). It is formed during foetal development and stabilizes during first two years of life. The accuracy and speed of currently deployed iris-based recognition system is promising and support the feasibility of large scale identification system based on iris information. It is also possible to detect contact lenses printed with a fake iris (Daugman, 1999). Every individual has a unique pattern of iris and even the identical twins do not have the similar patterns.
Retina: Retina recognition seeks to identify a person by comparing the pattern of blood vessels in the back of the human eye. Retina is protected in an eye itself and it is not easy to change or replicate the retinal vasculature. The retinal biometric system requires the eye to be placed close to the sensor, therefore it also implies cooperation of the subject. This system uses a camera with an electromechanical sensor which measures from a short distance (<3 cm) the natural reflective and absorption properties of the retina. A 7 –mW bulb illuminates the retina and the vein pattern is recorded with visible light and near infrared. (Bolle et al., 2004) · Ear: Ear were originally a part of the Bertillon system of human identification. The shape of the ear and structure of cartilaginous tissue of the pinna are distinctive. Matching the distance of salient points on the pinna from a landmark of the ear is used as a method of recognition. Ear recognition is not as reliable as face recognition. The combined recognition based on ear and face offers improved accuracy in identification.
DNA: DNA (Deoxyribose nucleic acid) identification (National Research council, 1992 & 1996) is often cited as ultimate biometrics, since DNA codes identify information in a digital form that is available from every cell in the body. The basis of DNA identification is the comparison of alternate forms (alleles) of DNA sequences found at identifiable points (loci) in nuclear genetic material. For identification, a set of loci is examined to determine which alleles are present at each chromosome. Any difference between enrolled and test samples indicates identity difference, while consistent identity between the samples indicate identity or a coincidence whose probability can be determined (Bolle et al., 2004). This method has some drawbacks: (a) contamination and sensitivity, since it is easy to steal a piece of DNA from an individual and use it for an un-disclosed purpose (b) no real-time application is possible because DNA matching requires complex chemical methods involving expert’s skills, (c) privacy issues since DNA sample taken from an individual is likely to show susceptibility of a person to some disease (Delac and Grgic, 2004).

Behavioural Biometrics:

Behavioural biometrics is based on the behavioural trait of an individual. The most common behavioural biometrics is signature, voice, gait and key stroke recognition. Brief introductions to this biometrics are given:
Signature: Signature is a simple, concrete expression of unique variations in human hand geometry. The way a person signs his or her name is known to be characteristic of that individual. Although signature requires contact with the writing instrument and an effort on the part of the user, they have been accepted in government, legal and commercial transaction as a method of authentication. With the proliferation of PDAs and tablet PCs, online signature may emerge as the biometric of choice in these devices. Signatures are a behavioural biometric that change over a period of time and are influenced by physical and emotional conditions of a subject. In addition to the general shape of the signed name, a signature recognition system can also measure pressure and velocity of the point of the stylus across the sensor pad (Jain et al., 2007).
Voice: Voice is a combination of both physical and behavioural biometric characteristics (Campbell, 1997). An individual’s voice is based on the physical characteristics such as vocal tracts, mouth, nasal cavities and lips that are used in creating a sound. These physical biometric characteristics are invariant but the behavioural aspect of human speech changes over time due to age, medical conditions e.g. cold, emotional state etc. Voice is also not very unique and appropriate in large scale identification. It has two approaches: Text dependent (recognition based on the fixed predetermined phrases) and text independent (recognition is independent of what a person is speaking). A text independent system is more difficult to design than text dependent voice recognition system. Speaker recognition is most useful in telephone based applications but the voice signal is typically degraded in the quality by the communication channel.
Gait: Gait refers to the peculiar way one walks and it is a complex spatio-temporal biometrics. It can be used to identify a person from a distant point. Therefore, this biometric is appropriate in surveillance scenario where the identity of a person can be superstitiously established. Recognition based on gait is somewhat newer biometrics and needs to be researched in detail. Gait is a behavioural biometric and is influenced by a number of factors such as body weight, walking surface, footwear, nature of clothing etc.
Keystroke: It is believed that each individual types on a keyboard in a unique way. This biometric is also not very distinctive and unique in identification but assists in recognition of an individual by offering sufficient discriminatory information. Keystroke pattern is also influenced by emotional state, keyboard position, type of keyboard etc. Advantage of using keystroke behaviour for recognition is that it can be easily observed unobtrusively as that person is keying the information. This biometric permits “continuous verification” of an individual’s identity over a session after the person logs in using a stronger biometric such as fingerprint or iris.
Odour: Each object spreads around an odour that is characteristic of its chemical composition and this could be used for distinguishing various objects. This would be done with an array of chemical sensors, each sensitive to a certain group of compounds. Deodorants and perfumes could lower the distinctiveness. (Delac and Grgic, 2004)