LLM Group 5 Criminal Law and Criminal Administration Forensic Science and Scientific Investigation of Crime 2024-25 Question Paper with Solutions

The serological sequence runs from sensitive to specific. For blood, the presumptive tests exploit the peroxidase activity of haemoglobin: the Kastle-Meyer phenolphthalein test, leucomalachite green, and luminol, which luminesces in darkness over traces of blood that have been washed away and is therefore the tool for a cleaned scene. These can exclude but cannot establish, because plant peroxidases and metal salts give false positives. Confirmation is by the microcrystal tests, Teichmann for haemin and Takayama for haemochromogen. Species is settled by the precipitin test using antiserum raised against human protein, now performed by gel diffusion or crossover electrophoresis. For semen the presumptive test is acid phosphatase, and confirmation is by microscopic identification of spermatozoa or by prostate specific antigen, which matters because it is detectable in a vasectomised or azoospermic man in whom no spermatozoa will be found. Saliva is identified by amylase.

India has no DNA statute. The DNA Technology (Use and Application) Regulation Bill, 2019 was withdrawn from the Lok Sabha in July 2023, so there is no DNA Regulatory Board, no statutory data bank and no compulsory accreditation of laboratories. The powers to take samples come from s.51 of the Bharatiya Nagarik Suraksha Sanhita, 2023, whose Explanation defines the examination of an arrested person to include blood, semen, swabs, sputum, sweat, hair and nail clippings by modern scientific techniques "including DNA profiling", from s.52 for a person arrested for rape and s.184 for the victim, and from the Criminal Procedure (Identification) Act, 2022, whose s.2(1)(b) includes biological samples and their analysis in "measurements", subject to the proviso to s.3 that a person arrested for an offence which is neither against a woman or a child nor punishable with seven years or more may not be obliged to give biological samples.

b) Forensic documents

Questioned document examination is the branch that establishes the authorship, authenticity and history of a document. Its subject matter is handwriting and signatures, alterations and additions, erasures and obliterations, indented impressions, ink and paper, typescript and printing, and security features on currency, stamps and identity documents.

Handwriting comparison proceeds on the premise that writing is a semi-automatic motor habit which is individual and which cannot be fully suppressed or fully imitated. The examiner compares class characteristics, which reflect the copybook system the writer was taught, and individual characteristics, which are personal: line quality, pen pressure and its variation, pen lifts, connecting strokes, proportions, slant, spacing, alignment, and the formation of particular letters. Adequate and contemporaneous standards are essential, and both requested specimens, written to dictation under observation, and collected specimens, written before the dispute arose, are needed, because a requested specimen alone can be deliberately distorted.

The law is specific. Section 39(1) of the Sakshya Adhiniyam makes expert opinion relevant on the identity of handwriting; s.41 makes relevant the opinion of a person acquainted with the handwriting of another; and s.72 empowers the Court itself to compare a disputed signature, writing or seal with one admitted or proved to be genuine. Section 349 of the Sanhita allows a Magistrate of the first class to order any person, including an accused, to give specimen signatures or handwriting, and a further proviso permits the order even against a person who has not been arrested, for reasons recorded in writing. That compulsion is constitutional because State of Bombay v. Kathi Kalu Oghad, AIR 1961 SC 1808 held that giving a specimen is a mechanical act furnishing material and not personal testimony, so Article 20(3) is not engaged.

The weight of the opinion is the contested part. In Magan Bihari Lal v. State of Punjab, (1977) 2 SCC 210, where a wagon of iron sheets was diverted by tampering with labels and the case rested on a handwriting expert, the Supreme Court held that expert opinion must be received with great caution, that it is unsafe to convict on it alone without substantial corroboration, and that this had almost become a rule of law.

c) Analysis of human bones

Skeletal analysis is the work of forensic anthropology and answers two sets of questions: who was this person, and what happened to them. Its material is bone recovered from a grave, a fire, a river, a mass disaster or a decomposed scene, where soft tissue no longer permits ordinary identification.

The first task is to establish that the material is bone, that it is human and not animal, and that it is of forensic rather than archaeological age, since the last determines whether there is any case at all.

Identification then rests on the four classical determinations. Sex is read most reliably from the pelvis, which is broad, with a wide sub-pubic angle and a large sciatic notch in the female, and secondarily from the skull, where the male has heavier brow ridges, a more prominent external occipital protuberance and a squarer mandible.

Identification may then be individualised by comparison with ante-mortem records: dental charts and restorations, which are highly individual, healed fractures and surgical implants, frontal sinus radiographs, which are individual, and DNA from the dense cortical bone of the femur or from tooth pulp. Where no records exist, facial reconstruction and craniofacial superimposition are used. Superimposition photographically or video-graphically overlays the skull on an ante-mortem photograph and tests whether the anatomical landmarks correspond, and its Indian standing was settled in Pattu Rajan v. State of Tamil Nadu, (2019) 4 SCC 771, where the Supreme Court accepted a superimposition result as part of the evidence, corroborated by other reliable testimony, while expressly acknowledging that the technique is not infallible.

The second set of questions concerns trauma. The bone records whether an injury was ante-mortem, showing healing; peri-mortem, occurring around the time of death, with the bone fracturing in a green and elastic state; or post-mortem, where the dry bone breaks with a different fracture pattern and colour. Sharp force, blunt force and projectile injuries leave distinguishable signatures, and the entry defect of a bullet in the skull is characteristically a clean internal bevel with external bevelling at the exit.

Conclusion. All three notes describe disciplines whose value is exactly as great as the record that accompanies the material. Forensic biology now individualises with a power no earlier technique approached, but Rahul shows that a two month gap in custody destroys it entirely. Questioned document examination remains the discipline in which the Supreme Court has been most openly divided about weight, and the Magan Bihari Lal and Murari Lal formulations are still not reconciled. Skeletal analysis produces ranges rather than facts, and the honest expression of the range, particularly in age estimation under s.94 of the Juvenile Justice Act, is the mark of a competent report.

The antecedents

The idea that a physical trace can prove a fact about a crime is old. Kautilya's Arthashastra, of about the fourth century before the common era, deals with the investigation of sudden death, the examination of the body and the detection of poisoning, and treats the interrogation and the physical examination as parts of one enquiry. The oldest surviving systematic treatment anywhere is Chinese: Song Ci's Xi Yuan Ji Lu, translated as The Washing Away of Wrongs, written in 1247, which distinguishes drowning from strangulation, describes the appearance of wounds inflicted before and after death, and records the celebrated sickle case in which flies settled on the invisible traces of blood on one reaper's sickle and identified the murderer.

In Europe the discipline begins with medicine rather than with chemistry. Ambroise Paré, the sixteenth century French military surgeon, systematically described the effects of violent death. The Italians Fortunatus Fidelis and Paolo Zacchia established legal medicine as a subject in the seventeenth century, Zacchia's Quaestiones Medico-Legales being the foundational text.

Fingerprints replaced it. Nehemiah Grew described ridge patterns in 1684 and Marcello Malpighi studied them soon after; Johann Purkinje classified nine patterns in 1823; William Herschel, a magistrate at Jungipoor in Bengal, began taking finger impressions on contracts in 1858 and satisfied himself over decades that they did not change; Henry Faulds published in Nature in 1880 proposing their use in criminal identification; and Francis Galton established persistence and individuality statistically in Finger Prints in 1892.

Systematisation came third. Hans Gross, an Austrian examining magistrate, published his Handbuch für Untersuchungsrichter in 1893, which set out for the first time how an investigation should use scientific assistance, and he is called the father of criminalistics. Edmond Locard established the first police laboratory at Lyon in 1910 in two attic rooms, and formulated the exchange principle: every contact leaves a trace, so the offender both takes something from the scene and leaves something at it. That principle is still the theoretical warrant for searching a scene at all.

Serology came fourth. Karl Landsteiner described the ABO blood groups in 1901, and Paul Uhlenhuth developed the precipitin test for species of origin in the same year, which meant that for the first time a stain could be shown to be human blood rather than animal.

The first Chemical Examiner's Laboratory was established in the Madras Presidency in 1849, under the Department of Health, principally to deal with poisoning cases. Similar laboratories followed at Calcutta in 1853, Agra in 1864 and Bombay in 1870. These are the oldest forensic institutions in the country and they were toxicological, which reflects what colonial administrators were most afraid of.

Bertillon's system reached India quickly, and an Anthropometric Bureau was established at Calcutta in 1892. It was superseded within five years, and by an Indian achievement. In 1897 the world's first Fingerprint Bureau was established at Writers' Building, Calcutta, after the Governor General's Council approved a committee report recommending that fingerprints be used to classify criminal records. Its superintendent was Edward Richard Henry, and the classification system that bears his name, which was adopted across the British Empire and much of the world and remained in use for a century, was in substance the work of two Indian sub-inspectors, Azizul Haque and Hem Chandra Bose. The point is worth making in an examination answer without overstating it: the Henry system was developed in Calcutta, by Indians, and India therefore did not import fingerprinting so much as export it.

The Directorate of Forensic Science Services under the Ministry of Home Affairs now controls seven Central Forensic Science Laboratories: Kolkata, the oldest, a centre of excellence in the biological sciences; Hyderabad, in chemical sciences; Chandigarh, in physical sciences; New Delhi, which is under the administrative control of the Central Bureau of Investigation; and Guwahati, Bhopal and Pune, which were set up as Central Forensic Institutes in 2011 and notified as laboratories in 2013.

DNA arrived in India remarkably early. The Centre for Cellular and Molecular Biology at Hyderabad, under Dr Lalji Singh, developed an indigenous probe in 1988, making India the third country in the world to develop its own DNA fingerprinting probe. Its first judicial acceptance was in Kunhiraman v. Manoj, II (1991) DMC 499, a maintenance claim begun in 1988 by a woman of Tellicherry in Kerala, in which profiling at the Centre established paternity; the High Court held that the evidence was admissible as expert opinion under what was then s.45 of the Evidence Act, on the same footing as ballistic and fingerprint opinion, and could by itself decide the dispute.

The statutory turn, 2022 to 2024

The most recent phase of the history is legislative, and it is where the answer should end, because it is the part no textbook older than 2024 contains.

The counterpoint belongs in the same paragraph. The DNA Technology (Use and Application) Regulation Bill, 2019, which would have created a regulatory board and compulsory accreditation for DNA laboratories, was withdrawn from the Lok Sabha in July 2023. So the powers have grown and the regulation has not.

Assessment

Two observations are worth making about the trajectory. The first is that the discipline has repeatedly advanced by discrediting itself: anthropometry was displaced by fingerprints, ABO grouping by DNA, and the first use of DNA in a criminal case exonerated a man who had confessed. A history that presents it as a series of triumphs misses the pattern.

The second is that India's institutional lead was early and was not sustained. A country that built the world's first fingerprint bureau in 1897 had no statute regulating forensic laboratories in 2026, and the courts have had to supply by direction what legislation has not: Kattavellai @ Devakar v. State of Tamil Nadu, 2025 INSC 845, decided on 15 July 2025, laid down the packaging, the forty-eight hour transmission rule and the Chain of Custody Register for the whole country because no statute had done so.

For full marks, cover: the single most common failure on this question is to describe INTERPOL as an international police force with officers who investigate and arrest. It has none. The answer that scores begins by saying what the organisation is not, then sets out its constitutional structure, then the four things it actually does, then the notices, then India's place in it, and then the criticism. On the Indian limb, one case does most of the work: Bhavesh Jayanti Lakhani, in which the Supreme Court held that a Red Corner Notice is not by itself a ground for arrest in India.

What INTERPOL is, and what it is not

The International Criminal Police Organization is an intergovernmental body of 196 member countries, with its headquarters at Lyon in France. It was founded at Vienna in 1923 as the International Criminal Police Commission, was effectively destroyed by its absorption into the German police apparatus during the Second World War, was reconstituted in 1946 with its seat in Paris, and took its present name and Constitution in 1956.

The National Central Bureau is the piece that makes the system work. Each member country designates a body within its own police structure to be the point of contact for all INTERPOL business. It is staffed by that country's own officers, operates under that country's own law, and is the channel through which every request passes. In India the National Central Bureau is the Central Bureau of Investigation, and it is known as NCB-New Delhi. India joined on 15 October 1949, and it is worth being accurate here, because quiz books frequently assert that India was a founding member and it was not; the organisation was founded in 1923.

Two other organs matter. The Advisers are experts appointed in a consultative capacity. The Commission for the Control of Files is an independent body that supervises the processing of personal data by the organisation and to which an individual may apply to have his data corrected or deleted, which is the only remedy an individual has against the organisation directly.

The two governing articles

Article 2 of the Constitution states the object: to ensure and promote the widest possible mutual assistance between criminal police authorities within the limits of the laws existing in the different countries and in the spirit of the Universal Declaration of Human Rights.

Third, operational police support services. Specialised units support member countries on terrorism, organised and emerging crime, cybercrime, financial crime, fugitive investigation, environmental and wildlife crime, human trafficking and the smuggling of migrants. The organisation deploys Incident Response Teams at the request of a member country after a major crime or a disaster, and its Disaster Victim Identification standards are the internationally accepted method for mass fatality identification.

Fourth, police capability building and training. The organisation trains investigators in member countries in the techniques of transnational investigation, and this is its least visible and most durable function.

The notice system

The notices are international requests for cooperation or alerts, published by the General Secretariat at the request of a National Central Bureau. There are eight, of which seven are colour coded.

The Indian position, and the case that governs it

The Indian law on what a Red Notice actually does was settled in Bhavesh Jayanti Lakhani v. State of Maharashtra, (2009) 9 SCC 551. The appellant was alleged to have removed a child in breach of a foreign court's custody orders, warrants of arrest had been issued abroad, and a Red Corner Notice had been issued at the request of the foreign authorities. The Maharashtra police proceeded on the footing that the notice authorised them to act against him.

That decision is the correct starting point for the Indian half of this question, because it locates the notice accurately: it is a request circulated among police forces, not a warrant, and it acquires legal force in India only through the Extradition Act. The practical route by which India secures a fugitive is therefore a Red Notice to locate him, followed by an extradition request under the 1962 Act, or in some cases a deportation request to the host State, which is faster and is used where the fugitive's immigration status permits it. The Fugitive Economic Offenders Act, 2018 operates alongside, allowing a Special Court to declare a person a fugitive economic offender and to confiscate his property, which is a domestic pressure applied while the international process runs.

The criticism

Article 3 is difficult to enforce and is exploited. The organisation depends on the information the requesting country gives it, and States have used Red Notices against political opponents, journalists and dissidents by presenting the case as ordinary crime. The reforms of the last decade, a strengthened Notices and Diffusions Task Force reviewing requests before publication and a reformed Commission for the Control of Files with power to order deletion, have reduced but not removed the problem.

Daya Singh Lahoria v. Union of India, (2001) 4 SCC 516, decided on 17 April 2001, is the leading Indian authority on the rule of specialty. The petitioner had been extradited to India from the United States, and Indian courts sought to try him for offences which did not appear in the extradition decree. The Supreme Court held that a fugitive brought into a country under an extradition decree can be tried only for the offences mentioned in the decree and for no other offence, and that the criminal courts have no jurisdiction to try him for any other offence until he has been returned to the surrendering State or given an opportunity to return. Section 21 of the Extradition Act, 1962 embodies the doctrine.

Conclusion. INTERPOL is not a police force but a permanent machinery for cooperation between 196 national police services, constituted by a General Assembly, an Executive Committee, a General Secretariat at Lyon and a National Central Bureau in every member country, which for India is the Central Bureau of Investigation, India having joined on 15 October 1949. Its functions are four: the secure I-24/7 network, the operational databases, specialised operational support including Incident Response Teams and Disaster Victim Identification, and training.

Its most visible product is the notice system, of which the Red Notice is the best known and the least well understood, since Bhavesh Jayanti Lakhani establishes that in India it is not a ground for arrest and that extradition depends on the Extradition Act, 1962. Its central weakness is structural: Article 3 forbids political activity, but the organisation must assess political motivation on material supplied by the very State that may be acting politically, and the individual's only direct remedy is to an internal Commission rather than to a court.

What narco-analysis is

Narco-analysis is the questioning of a subject who has been brought, by the controlled intravenous administration of a barbiturate, into a state in which the inhibitory control of speech is depressed. The drug is usually sodium pentothal, chemically thiopentone sodium, an ultra-short-acting barbiturate; sodium amytal and scopolamine have also been used. The popular name, "truth serum", is inaccurate and the inaccuracy is the whole of the scientific objection: no drug compels truth.

The pharmacology is worth stating because the legal safeguards follow it. Barbiturates depress the central nervous system in a descending order, suppressing the higher cortical functions that govern deliberation and self-monitoring before they suppress the brain-stem functions that govern respiration. There is therefore a window, the hypnotic stage between full consciousness and surgical anaesthesia, in which the subject can still speak but has reduced capacity to construct or sustain a deliberate account. The purpose of the infusion is to hold the subject in that window.

The subject is medically examined before the test, and the technique is contraindicated in cardiac disease, respiratory disease, hepatic or renal impairment, in pregnancy, and in the elderly. Deaths under barbiturate anaesthesia are a known risk of anaesthetic practice generally, and this is the reason the procedure can only be conducted in a hospital or a facility with equivalent resuscitation capacity.

Efficacy

Efficacy asks a narrow question: does the technique do the thing it is supposed to do, namely produce speech from a subject who was withholding it. On that narrow question the answer is a qualified yes, and honesty requires saying so, because an answer that dismisses the technique entirely does not explain why investigating agencies fought so hard for it.

Subjects in the hypnotic stage do speak, at length, and do disclose matters previously withheld. Investigating agencies have reported operational value in the form of leads, the location of a weapon or a body, the identity of a confederate, the disposal route of stolen property. In the Indian experience the technique was most heavily used in high profile investigations of the 2000s, including large financial frauds and terrorism cases, precisely because agencies believed it generated leads.

Confabulation. The subject fills gaps in recollection with plausible material and reports it with the confidence of genuine memory. He is not lying, and the video record will show a subject speaking without any of the signs of deception, which makes a confabulated account more persuasive to a viewer than the truth would be.

Indistinguishability of fantasy from recollection. Nothing in the output separates what the subject experienced from what he feared, imagined, or was told by others.

Absence of validation. There is no published error rate, no controlled study establishing the ratio of true to false statements, and no accepted method of scoring the output. Applying the admissibility conditions from Ramesh Chandra Agrawal v. Regency Hospital Ltd., (2009) 9 SCC 709, which require that expert evidence be based on reliable principles and given by a qualified expert in a recognised field, narco-analysis fails on the reliability limb before any constitutional question is reached.

The consequence that examiners look for is this: the technique cannot even reliably exonerate. A subject capable of confabulating an admission is equally capable of confabulating a denial, so a clean narco result proves nothing in the subject's favour either.

Selvi: the four propositions

Selvi v. State of Karnataka, (2010) 7 SCC 263, decided on 5 May 2010, disposed of a group of appeals and reversed the High Court position. Four propositions must be given.

One. The compulsory administration of narco-analysis violates Article 20(3). The reasoning is that narco-analysis produces a testimonial act. The subject is made to speak, and there is no principled reason to treat speech in a drug-induced state differently from answers given in an ordinary interrogation. It therefore falls within "to be a witness" as construed in State of Bombay v. Kathi Kalu Oghad, AIR 1961 SC 1808, which distinguished personal testimony, protected by Article 20(3), from material evidence such as a fingerprint or a handwriting specimen, which is not. This is precisely the distinction the Bombay High Court had drawn the other way in 2004.

Two. Compulsory administration also violates Article 21, as an unjustified intrusion into mental privacy and a procedure that is not fair, just and reasonable. That limb is independently important because it protects witnesses and suspects who are not persons "accused of an offence" and who therefore cannot invoke Article 20(3) at all.

• He must be informed of the legal, physical and emotional implications of the test, and he must have access to a lawyer when that information is given.
• His consent must be recorded before a Judicial Magistrate, not before the police.
• At the hearing before the Magistrate, the lawyer must be permitted to explain the implications to him, and the accused must be told that the statement made will not be a confessional statement to a Magistrate but will have the status of a statement made to the police.
• The Magistrate must consider all factors relating to detention, including the length of detention and the nature of the interrogation.
• The actual recording of the test must be done in an independent agency, such as a hospital, in the presence of a lawyer.
• A full medical and factual narration of the manner in which the information was received must be recorded, including the physical, emotional and legal condition of the subject.

Setting these out as a sequence, rather than summarising them as "safeguards", is what distinguishes an answer that has read Selvi from one that has read about it.

The comparative position is the same. In Townsend v. Sain, 372 U.S. 293 (1963), where a suspect in heroin withdrawal was given phenobarbital and hyoscine by a police physician and then confessed to murder, the United States Supreme Court held that the voluntariness standards applicable to physical intimidation and psychological pressure apply equally to a drug-induced statement, and observed that it is difficult to imagine a confession less the product of a free intellect than one brought about by a drug having the effect of a truth serum.

Conclusion. Narco-analysis is interrogation conducted while the subject is held by a titrated barbiturate infusion in the hypnotic stage between consciousness and anaesthesia. It is moderately effective at producing speech and wholly unreliable as a source of truth, because suggestibility and confabulation are properties of the very state it induces and because no error rate for it has ever been established, so it fails the reliability condition in Ramesh Chandra Agrawal independently of any constitutional objection.

For full marks, cover: two commands. "Enlist" wants a genuine list, which is worth about six marks if it is organised rather than random. "Explain any three in detail" wants three expositions of roughly five hundred words each, and the choice of three is where candidates decide their own mark. Pick devices you can attach a statute and a case to. The three explained here are the gas chromatograph with mass spectrometer, the mobile device forensic extraction system, and the body-worn camera, chosen because each carries a live Indian legal controversy.

The list, arranged by what the device is for

Two observations carry marks. First, only some of these produce anything admissible: a metal detector and a field test kit generate suspicion that justifies a search, a chromatograph and a genetic analyser generate evidence, and a polygraph after Selvi generates neither. Second, the devices in the last three rows create records about the police, and Indian courts have increasingly used them for that purpose rather than against the accused.

The legal significance, and where it bites hardest. In narcotics prosecutions the instrument does not merely establish that a substance is contraband; it fixes the sentence. The Narcotic Drugs and Psychotropic Substances Act, 1985 grades punishment by whether the quantity is small, more than small but less than commercial, or commercial, and the difference between the top and bottom bands is the difference between up to a year and ten to twenty years with a heavy fine.

The controversy is over what is weighed. In E. Micheal Raj v. Intelligence Officer, Narcotic Control Bureau, (2008) 5 SCC 161, the Supreme Court held that in the case of a mixture of a narcotic drug with a neutral substance, it is the actual content by weight of the offending drug that determines whether the quantity is small or commercial, so a large quantity of a heavily diluted preparation could fall in the lower band. That decision governed for twelve years and remains in many textbooks.

2. The mobile device forensic extraction system

How it works. A mobile extraction system is a hardware and software combination that acquires the contents of a phone or tablet without altering them. It works at three levels. A logical extraction copies the data the operating system exposes through its own interfaces: contacts, messages, call logs, photographs and app data. A file system extraction copies the underlying file structure, including databases that hold deleted records still present in unallocated slack. A physical extraction copies the raw memory bit by bit, which permits recovery of deleted material and of unallocated space, and requires exploiting or bypassing the device's protections.

The forensic discipline around it is more important than the instrument. The device is isolated from the network, in a Faraday bag or in flight mode, so that it cannot receive a remote wipe command. A hash value is computed over the acquired image at the moment of acquisition and recomputed later, so that any alteration is demonstrable. The analyst works on a copy, never the original.

Section 39(2) of the Adhiniyam is directly relevant and is new: where the Court has to form an opinion on information stored in any computer resource or other electronic form, the opinion of the Examiner of Electronic Evidence under s.79A of the Information Technology Act, 2000 is a relevant fact, and the Explanation deems him an expert. And s.193(3)(i) of the Sanhita now requires the police report to state "the sequence of custody in case of electronic device", which is a statutory chain of custody requirement specific to this class of evidence.

Limits. Full-disk encryption on modern handsets defeats physical extraction without the passcode, and whether a court may compel a passcode is unsettled in India: a passcode is arguably testimonial and so within Selvi and Kathi Kalu Oghad, while a biometric unlock is arguably material and so outside it. Extraction is indiscriminate, recovering the whole of a person's private life to prove one message, which raises a proportionality objection under K.S. Puttaswamy v. Union of India, (2017) 10 SCC 1. And an extraction report frequently runs to thousands of pages that no party reads in full.

The Indian legal setting. Two developments matter. The first is judicial. In Paramvir Singh Saini v. Baljit Singh, (2021) 1 SCC 184, decided on 2 December 2020, the Supreme Court, dealing with custodial violence, directed the installation of closed circuit television with night vision and audio at every entry and exit point, lock-up, corridor, lobby, reception area, veranda, Inspector's room, station hall and compound of every police station, with footage preserved for eighteen months and in no case less than a year, and extended the direction to the offices of central agencies that interrogate and hold accused persons, grounding all of it in Article 21. The body-worn camera is the mobile counterpart of that regime, covering the officer once he leaves the station, which is where the fixed cameras cannot reach.

The second is statutory. The Bharatiya Nagarik Suraksha Sanhita, 2023 now requires recording in several places: s.105 requires the process of search and seizure, and the preparation of the list of seized articles, to be recorded by audio-video electronic means, preferably a mobile phone, and forwarded to the Magistrate without delay; s.185 carries a similar requirement for a search by a police officer; and s.176(3) requires videography of forensic collection at the scene of a serious offence. The device that in practice discharges these duties is the officer's own phone or a body-worn camera.

The mobile device forensic extraction system produces the evidence that dominates modern investigations, but it delivers it into the strict certificate regime of s.63(4) of the Sakshya Adhiniyam as enforced by Arjun Panditrao, and it raises an unresolved question about compelling a passcode. The body-worn camera is the device whose principal subject is the police officer, and it discharges duties the Sanhita now imposes in ss.105, 176(3) and 185, complementing the station cameras directed in Paramvir Singh Saini. In every case the device is worth in court precisely what the procedure around it is worth.

Individuality. No two fingers, including those of identical twins and including two fingers of the same person, bear the same ridge configuration. Friction ridge skin forms between about the tenth and the sixteenth week of gestation, and the detailed pattern is produced by the differential growth stresses on the volar pads at that time, which are not genetically specified. That is why monozygotic twins, who share a genome, do not share fingerprints, and it is the strongest single fact in the discipline's favour.

Permanence. The pattern is fixed before birth and does not change through life except in size. Superficial injury regenerates identically; only injury deep enough to destroy the dermal papillae produces a permanent scar, and the scar is itself an individual characteristic.

Classifiability. The patterns fall into a small number of classes, which is what makes searching a large collection possible. Without this the first two would be of no practical use.

Development of latent prints is chosen according to the surface. On non-porous surfaces such as glass, metal and plastic, powder dusting is used with grey, black, magnetic or fluorescent powders, and cyanoacrylate fuming, in which superglue vapour polymerises on the ridge residue to produce a white durable ridge, is the standard laboratory method. On porous surfaces such as paper and cardboard, the reagents target the amino acids: ninhydrin, which produces the characteristic purple Ruhemann's purple; DFO, which fluoresces and is more sensitive; and physical developer for surfaces that have been wet. Iodine fuming develops fresh prints in sebaceous residue and is transient, so it must be photographed at once. Small particle reagent works on wet non-porous surfaces. Vacuum metal deposition is used for the most difficult substrates such as plastic bags. Alternate light sources are used throughout to make treated prints fluoresce against the background.

Patterns: the three classes and their subdivisions

Pattern classification depends on two landmarks. The delta is the triangular point where ridge flows diverge, at the point nearest the divergence of the type lines. The core is the approximate centre of the pattern.

Loops. One or more ridges enter from one side, recurve, and exit on the same side from which they entered, passing between the delta and the core. A loop has exactly one delta and one core. Where the ridges flow towards the ulnar side, that is the little finger, it is an ulnar loop; where they flow towards the radial side, the thumb, it is a radial loop. The distinction is made by reference to the hand from which the print came, which is why an unknown chance print cannot be classified as ulnar or radial without more.

Whorls. Whorls have two or more deltas and at least one ridge that makes a complete circuit. The plain whorl has two deltas and a recurving ridge in front of each, with an imaginary line between the deltas touching or crossing one recurving ridge. The central pocket loop whorl is a loop in which one or more ridges recurve to form a small pocket, with the line between the deltas failing to touch the inner recurving ridge. The double loop whorl has two separate loop formations and two deltas. The accidental whorl contains two or more different patterns, or conforms to none of the definitions, and is the residual class. Some older classifications, including in Indian textbooks, group whorls other than the plain whorl under the head of composites.

Examiners speak of three levels of detail. Level one is the overall pattern, which can exclude but never identify. Level two is the minutiae and their relative positions, which is where identification is made. Level three is the detail within the ridge itself: the position and shape of the sweat pores, which is poroscopy, and the shape of the ridge edges, which is edgeoscopy. Level three detail requires a high quality impression and is used where the print is small.

The comparison method is called ACE-V: analysis of the questioned print for suitability, comparison with the known print, evaluation to a conclusion of identification, exclusion or inconclusiveness, and verification by a second examiner. The number of matching minutiae required has never been fixed by any scientific rule; the older practice of demanding eight, twelve or sixteen points was a matter of national convention, and the modern position in most jurisdictions is a holistic sufficiency judgment, which is exactly the practice the critics attack.

That system has been superseded operationally by automation. The National Automated Fingerprint Identification System, launched by the National Crime Records Bureau on 17 August 2022, holds a national searchable repository, assigns each arrested person a ten-digit National Fingerprint Number, and is integrated with the Crime and Criminal Tracking Network and Systems so that a chance print from one State can be searched against records created in another. It is worth being clear that such a system returns a candidate list and not an identification; the identification is still made by a human examiner.

The law

Expert opinion on the identity of finger impressions is made relevant by s.39(1) of the Bharatiya Sakshya Adhiniyam, 2023, which names finger impressions expressly. The Director of the Finger Print Bureau is a Government scientific expert under s.329(4)(c) of the Bharatiya Nagarik Suraksha Sanhita, 2023, so his report may be used as evidence, and under the second proviso to s.330 he need not attend unless a party disputes it.

The Indian case that supplies the caution is Mohd. Aman v. State of Rajasthan, (1997) 10 SCC 44, decided on 8 May 1997. The conviction rested on a chance print developed on a brass jug recovered from the scene of a murder. The specimen prints of the accused had been taken three separate times because the Bureau kept returning them as unclear, and on none of those occasions were they taken before or under the order of a Magistrate as s.5 of the Identification of Prisoners Act then required. The jug, moreover, had been in police custody at a time when the accused was also in police custody. The Supreme Court held that in those circumstances the possibility of fabrication could not be excluded, described the gap as a glaring missing link, and acquitted.

The standing illustration is the case of Brandon Mayfield. After the Madrid train bombings of 11 March 2004, in which 191 people were killed, a latent print from a bag of detonators was matched by the Federal Bureau of Investigation to Mayfield, a lawyer in Oregon who had never been to Spain. The identification was confirmed by more than one examiner. The Spanish National Police then identified the print as that of an Algerian national, Ouhnane Daoud, and Mayfield was released after nineteen days in detention, receiving an apology and a settlement of two million dollars. The case is used across the world to make the point that verification by a second examiner who knows the first examiner's conclusion is not independent verification at all.

Conclusion. Fingerprints occur at a scene in three types, latent, patent and plastic, and the development method is chosen by the surface: powder and cyanoacrylate for non-porous, ninhydrin, DFO and physical developer for porous. Their patterns fall into three classes, arches with no delta, loops with one and whorls with two, subdivided into plain and tented arches, ulnar and radial loops, and plain, central pocket loop, double loop and accidental whorls, with ridge counting subdividing loops and ridge tracing subdividing whorls. Classification narrows the search; identification is made on the level two minutiae by the ACE-V method.

For full marks, cover: two of three, about twelve and a half marks each. All three are written out. The third is the one to prefer if you know it, because entry and exit wound differentiation is a closed topic with a definite answer, it can be tabulated, and it is easy to score highly on; the other two are broader and it is easier to write a page that says nothing. In each note, get to the practical determination the discipline actually makes for a court, and name at least one authority.

a) Forensic anthropology

Forensic anthropology is the application of physical and skeletal anthropology to medico-legal problems, and it takes over at the point where ordinary medical examination fails: where a body is skeletonised, burnt, dismembered, decomposed beyond recognition, or fragmented among the remains of many others.

Its work has four stages, and setting them out as stages is what turns a vague note into a good one.

Building the biological profile. This is the classical work and rests on four determinations: sex, principally from the pelvis and secondarily from the skull; age, from dental eruption, from the sequence of epiphyseal fusion through adolescence into the mid twenties, and thereafter from degenerative changes at the pubic symphysis, the sternal rib ends and the cranial sutures; stature, by regression from the maximum length of a long bone using population-specific formulae, with a standard error of several centimetres; and ancestry, from craniofacial morphology, which is the weakest of the four.

The Indian legal use that matters most is age estimation, and it is governed rather than free. Section 94 of the Juvenile Justice (Care and Protection of Children) Act, 2015 places the ossification test last, after the matriculation or school certificate and after the birth certificate from a corporation, municipal authority or panchayat, and permits it only in the absence of both. In Jarnail Singh v. State of Haryana, (2013) 7 SCC 263 the Supreme Court held that this procedure applies also to determining the age of a child who is the victim of an offence, which is how it reaches prosecutions under the Protection of Children from Sexual Offences Act, 2012. The anthropologist's estimate is a range, and it is least reliable in the band around eighteen years where it is most often needed.

b) Forensic toxicology

Forensic toxicology is the branch that detects and interprets poisons, drugs and their metabolites in biological material for legal purposes. It divides into three fields: post-mortem toxicology, which asks whether a poison caused or contributed to death; human performance toxicology, which asks whether a person was impaired, as in driving and workplace cases; and forensic drug testing, which asks whether a substance is a controlled drug.

The chain of work runs from collection to interpretation. At autopsy the viscera are collected and preserved: stomach with contents, a portion of small intestine with contents, liver, kidney, and separately blood and urine. The standard preservative for viscera is saturated saline, and rectified spirit is used except where alcohol is suspected, because it would destroy the very analysis required, which is a classic examination point. The samples are sealed, labelled and sent to the Chemical Examiner.

Analysis proceeds in two stages: a broad screen, by immunoassay or thin layer chromatography, which is sensitive but not specific, followed by confirmation by gas chromatography with mass spectrometry or by liquid chromatography with tandem mass spectrometry, which identifies and quantifies. The two-stage structure is the same one that governs serology and exists for the same reason.

Substantively, s.123 of the Bharatiya Nyaya Sanhita, 2023 punishes causing hurt by means of poison or any stupefying, intoxicating or unwholesome drug with intent to cause hurt or to facilitate an offence, and s.103(1) punishes murder, which is the charge where the poisoning is fatal. Section 185 of the Motor Vehicles Act, 1988 fixes the drink-driving threshold at thirty milligrams per hundred millilitres of blood. And the Narcotic Drugs and Psychotropic Substances Act, 1985 grades punishment by quantity, on which Hira Singh v. Union of India, (2020) 20 SCC 272 overruled E. Micheal Raj v. Intelligence Officer, NCB, (2008) 5 SCC 161 and held that the whole weight of the mixture, including any neutral substance, determines whether the quantity is small or commercial.

c) Entry and exit wounds by firearms

Distinguishing the entry from the exit wound is the single most consequential determination in firearm injury cases, because it establishes the direction of fire, and the direction of fire is what separates suicide from homicide, and what tests the account of any accused who claims he fired in self-defence from a particular position.

The important exception, which good answers give, is the shored exit wound. Where the skin at the point of exit is supported by a firm surface, a wall, a floor, a tight belt or a stiff garment, the everting skin is pressed against that surface and abrades, producing a false abrasion collar around an exit wound. It is broader and more irregular than a true abrasion collar, but it has been misread as an entry more than once.

Range determination is made from the entry wound alone, and it is really a second question in this topic.

Bone tells the same story more reliably than skin. Where a bullet perforates the skull, the entry defect is a clean punched-out hole on the outer table with internal bevelling, the inner table being wider; at exit the position is reversed, with external bevelling. Because bone does not retract elastically, this is often decisive where the soft tissue findings are equivocal.

The legal significance is direct. Whether a wound is entry or exit, and at what range it was inflicted, determines whether the death is consistent with the prosecution's account or with the defence's, and it is the medical evidence that either corroborates or destroys ocular testimony. Under Solanki Chimanbhai Ukabhai v. State of Gujarat, (1983) 2 SCC 174, that medical evidence is ordinarily corroborative and displaces eyewitness testimony only where it rules out the eyewitness account altogether. And Sukhwant Singh v. State of Punjab, (1995) 3 SCC 367 supplies the complementary point about the weapon: where both the firearm and the crime cartridge are recovered, the opinion of the ballistic expert is of considerable importance, and failing to obtain it damages the prosecution case to a great extent.