Finger Impression and Fingerprint Evidence under the Bharatiya Sakshya Adhiniyam, 2023: Admissibility, Comparison and Evidentiary Value

Finger impressions are one of only two forms of identification expressly named in Section 39, and they have been received by Indian courts for longer than almost any other scientific evidence. The reason is that the discipline rests on two propositions nobody seriously disputes: that the friction ridge pattern on a finger is unique to the individual, and that it does not change from birth to death. What is disputed, and what decides most cases, is everything that happens between the finding of a mark and the giving of an opinion about it.

1. The Statutory Basis

Finger impressions are named expressly, so no question arises whether the discipline is a 'science' within the section. The grounds of the opinion are relevant under Section 45, and facts supporting or contradicting it are relevant under Section 40, which is what allows the method of comparison to be probed in cross-examination.

The closing words are important and are frequently overlooked. Section 72 permits comparison of a disputed finger impression with one admitted or proved to be genuine, and permits the court to direct a person present in court to give an impression for that purpose. The court may therefore make its own comparison, though in practice it does so only where the difference is gross or where it confirms an opinion already given.

2. The Basis of the Discipline

Friction ridges form on the fingers, palms and soles before birth, and the pattern they produce is determined by conditions in the womb rather than by inheritance. Two propositions follow, and together they are the whole foundation of the evidence.

Permanence. The pattern does not change with age, growth or wear. Superficial injury heals in the original pattern; only injury deep enough to destroy the dermal layer leaves a permanent scar, and a scar is itself an identifying feature.

Individuality. No two persons, including identical twins, have been found to share a pattern. Identical twins share their DNA but not their fingerprints, which makes the discipline capable of doing something DNA cannot.

Patterns are classified into broad families — loops, whorls and arches — which are class characteristics and serve only to narrow the field. Identification depends on the ridge characteristics or minutiae within the pattern: the points at which a ridge ends, divides into two, forms an island, or takes some other identifiable course. It is the number, type and relative position of these characteristics that an examiner compares.

3. Kinds of Marks and Their Collection

Marks found at a scene fall into three kinds, and the differences matter both to how they are recovered and to what they are worth.

Patent prints are visible to the eye, left in a substance such as blood, ink, grease or dust. They are photographed in position before anything else is done.

Plastic prints are impressions in a soft material — wet paint, putty, wax, soap. Like patent prints they are visible, and they are photographed and where possible preserved with the object.

Latent prints are invisible, left by the natural secretions of the skin, and must be developed before they can be seen. This is the commonest kind found at a scene and the most vulnerable to error, because development, photography and lifting all involve handling that may damage or destroy the mark.

Whatever the kind, the matters that must be established are the same: where the mark was found, described with precision; when it was found and by whom; what was done to develop it; that it was photographed in position before lifting; and how the lift was preserved, labelled and transmitted. A print produced without evidence of where it came from establishes nothing at all.

4. Taking Specimen Impressions

Comparison requires a known specimen, and the taking of specimens raises two questions — whether a person may be compelled, and under what authority.

On the statutory side, the position has been consolidated by the Criminal Procedure (Identification) Act, 2022, which replaced the Identification of Prisoners Act, 1920. The 2022 Act permits the taking of 'measurements' from persons in the categories it specifies, and the expression is defined widely enough to include finger impressions, palm prints, footprint impressions, photographs, iris and retina scans, physical and biological samples and their analysis. It also provides for the storage and preservation of such records.

Section 72 of the Adhiniyam supplies a further and narrower power: the court may direct a person present in court to give an impression for the purpose of enabling the court to make a comparison. That power is exercisable by the court in a proceeding before it, and is distinct from the investigative power under the 2022 Act.

5. Evidentiary Value

Fingerprint identification is an individual characteristic, and this places it among the small group of forensic disciplines capable of identifying a single source rather than merely narrowing the field. Where a chance print from the scene is properly recovered, and a properly taken specimen matches it, the identification is treated as reliable, and there is no rule requiring corroboration.

What the identification establishes, however, is narrower than is often assumed. It establishes that the person touched the surface. It says nothing about when he touched it, and nothing about why. A latent print may survive for a long period on a protected surface, and its presence is consistent with contact at any time during that period.

The consequence is that the value of a fingerprint depends almost entirely on where it was found. A print on the inside of a window frame forced open, on a weapon recovered from a concealed place, on a cash box, or on a surface within a room the accused had no occasion to enter, is powerful because there is no innocent explanation for the contact. A print on a portable article, on a common surface, or on an object the accused might lawfully have handled establishes contact without establishing anything relevant.

6. Limitations and Lines of Attack

Five weaknesses recur, and each should be put to the expert in a contested case.

Partial and smudged prints. A chance print is rarely a full impression. Where only a portion of the pattern is available, the number of comparable characteristics falls, and the confidence of the identification falls with it. The expert should be asked how much of the pattern was available and how many characteristics were compared.

No indication of time. The discipline offers no method of dating a latent print. Where the accused had lawful access at some earlier time, the print is consistent with that access.

Innocent transfer and handling. Where an article was handled by police personnel, witnesses or others before it was examined, a print may have been deposited after the occurrence. The record of who handled the article, and when, is therefore material.

Absence proves little. The failure to find the accused's prints at a scene is not evidence that he was not there. Most contacts do not leave usable prints, surfaces may be unsuitable, and prints may be destroyed by handling or weather.

The examiner's judgment. Comparison is a judgment about whether characteristics correspond, and although the discipline is well established, the conclusion is an opinion and not a measurement. An examiner who states a conclusion without stating the number of characteristics, without producing enlargements, and without addressing any apparent differences has given the court nothing to test, and Jai Lal applies to him as to any other expert.

7. Proving the Evidence

The links that must be established are the same as in any forensic case, and the failure is ordinarily at one of them rather than in the science.

1. Discovery of the mark — the person who found it, where, when and in what condition, and that the place was under observation from the time of the occurrence.
2. Photography in position before any attempt at lifting, so that the location of the mark is beyond dispute.
3. Development and lifting — the method used and by whom, and the preservation and labelling of the lift.
4. Sealing and custody of the lift or the article bearing the mark, with the seal described and the article kept in safe custody.
5. Taking of the specimen — by whom, in whose presence, and whether attested by a Magistrate.
6. Transmission of both to the bureau in sealed condition, and the condition of the seals on receipt.
7. The comparison — the method, the number of matching characteristics, whether enlargements were prepared, and whether any difference was observed and how it was explained.

8. The Position Stated Shortly

1. Finger impressions are expressly named in Section 39(1), so no question arises about whether the discipline qualifies.
2. Section 72 permits comparison by the court and empowers it to direct a person present in court to give an impression, since the section applies to finger impressions with necessary modifications.
3. Article 20(3) does not protect against giving an impression, because an impression conveys no personal knowledge — Kathi Kalu Oghad.
4. The Criminal Procedure (Identification) Act, 2022 supplies the investigative power to take measurements, including finger and palm impressions.
5. Identification rests on ridge characteristics, not on the broad pattern, and no fixed number is prescribed — what is required is sufficient matching characteristics with no unexplained difference.
6. A print establishes contact, not time and not purpose, and its value therefore depends almost entirely on where it was found.
7. The integrity of both the chance print and the specimen must be proved — Mohd. Aman — and specimens taken before a Magistrate remove the standard objection.
8. Absence of prints proves very little, since most contacts leave no usable impression.

9. Related Topics and Provisions