1. Introduction

Crime investigation genetic testing refers to the collection, examination, comparison, storage and use of biological samples and DNA profiles for identifying suspects, victims, missing persons and deceased individuals in criminal investigations.

DNA (Deoxyribonucleic Acid) testing is an important forensic technique because it can help establish whether biological material recovered from a crime scene originated from a particular individual.

Common biological samples include:

Blood and bloodstains.

Saliva and saliva traces.

Hair containing roots.

Semen and other bodily fluids.

Skin cells and biological material recovered from objects.

Bone, teeth and other human remains.

Buccal swabs collected from the inside of the mouth.

Genetic testing can assist in investigating murder, rape, sexual assault, kidnapping, human trafficking, unidentified bodies and other serious offences.

However, the use of genetic information creates important legal questions concerning privacy, bodily autonomy, self-incrimination, consent, evidentiary reliability, wrongful identification and protection against misuse of personal genetic information.

In India, crime investigation genetic testing is governed by constitutional protections, criminal procedure legislation, evidence law, forensic standards and judicial decisions.

2. Constitutional framework governing genetic testing

A. Article 20(3): Protection against self-incrimination

Article 20(3) of the Constitution of India provides that no person accused of an offence shall be compelled to be a witness against himself or herself.

This protection becomes relevant when investigating authorities require an accused person to provide biological samples for DNA examination.

An important legal distinction exists between:

Testimonial evidence, such as compelled statements, confessions and personal knowledge.

Physical evidence, such as fingerprints, handwriting specimens and bodily samples used for forensic examination.

DNA evidence is generally treated as physical or scientific evidence rather than testimonial communication.

Nevertheless, compulsory collection must comply with applicable statutory authority and constitutional safeguards.

B. Article 21: Right to life, dignity and privacy

Article 21 protects personal liberty, dignity and privacy.

Genetic information is particularly sensitive because it may reveal information concerning:

Biological identity.

Familial relationships.

Hereditary characteristics.

Genetic predispositions.

Biological parentage.

Consequently, genetic testing should satisfy legality, legitimate investigative purpose, necessity and proportionality.

C. Article 14: Equality and non-arbitrariness

Investigating authorities must apply genetic-testing procedures fairly and without arbitrary discrimination.

Selective testing, discriminatory genetic profiling and arbitrary retention of DNA profiles may raise constitutional concerns.

D. Article 22: Procedural safeguards

Where genetic testing forms part of an arrest or criminal investigation, applicable constitutional protections concerning arrest and legal representation must also be respected.

3. Statutory framework governing genetic testing in India

A. Criminal Procedure (Identification) Act, 2022

The Criminal Procedure (Identification) Act, 2022 is an important statute governing the collection and preservation of identification records for criminal investigation.

It replaced the Identification of Prisoners Act, 1920.

Its provisions are particularly relevant to biological samples and forensic identification.

Important provisions:

Section 2 – Definition of measurements

The expression measurements includes:

Physical and biological samples.

Analysis of biological samples.

Fingerprints and palm prints.

Photographs.

Iris and retina scans.

Other specified identification characteristics.

Section 3 – Taking of measurements

The section authorises the collection of measurements from specified categories of persons, including arrested persons and convicted persons.

An important proviso protects certain arrested persons from being obliged to provide biological samples under this section. The exception does not apply to offences against women or children or offences punishable with imprisonment of at least seven years.

This is an important distinction: the provision does not create an unrestricted power to collect DNA from every person arrested for every offence.

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Section 4 – Collection, storage and preservation

The National Crime Records Bureau (NCRB) is empowered to:

Collect measurement records.

Store and preserve records.

Process records with relevant criminal records.

Share records with law-enforcement agencies.

Destroy records in accordance with applicable provisions.

The Act provides for digital retention for 75 years from the date of collection, subject to its statutory provisions and exceptions.

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Section 5 – Power of Magistrate

A Magistrate may direct a person to provide measurements when satisfied that doing so is expedient for an investigation or proceeding.

Section 6 – Resistance or refusal

The Act provides for consequences where a person resists or refuses the taking of measurements in circumstances covered by the legislation.

Section 7 – Legal protection

The Act provides legal protection for actions undertaken in good faith under its provisions.

Legal significance: The Act establishes a statutory framework for collecting, processing and preserving identification information. Its application must nevertheless be consistent with constitutional protections and the specific conditions imposed by law.

B. Criminal Procedure (Identification) Rules, 2022

The Central Government notified the Criminal Procedure (Identification) Rules, 2022, on 19 September 2022.

These Rules establish procedures concerning:

Collection of measurements.

Identification of authorised personnel.

Recording and preservation of measurements.

Transmission of information to the NCRB.

Storage and processing of records.

Sharing of identification records.

Destruction and disposal of records.

The Rules also provide for technical and administrative procedures concerning the handling of identification records.

The NCRB has an important role in administering the national record-management framework.

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C. Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS)

The Bharatiya Nagarik Suraksha Sanhita, 2023 came into force on 1 July 2024 and replaced the Code of Criminal Procedure, 1973.

Its provisions directly address scientific examination during criminal investigations.

Section 51 – Examination of accused by medical practitioner

This provision permits medical examination of an arrested accused where reasonable grounds exist to believe that examination may provide evidence relating to the offence.

Its explanation expressly includes modern scientific techniques such as DNA profiling.

Biological materials covered include:

Blood and bloodstains.

Semen.

Swabs in sexual offences.

Sputum and sweat.

Hair samples.

Fingernail clippings.

The examination must be reasonably necessary for discovering relevant facts.

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Section 52 – Examination of a person accused of rape

This provision governs the medical examination of a person arrested on a charge of rape and includes procedures for collecting relevant forensic material.

It is important in cases involving sexual assault, identification of biological material and comparison of DNA profiles.

Section 53 – Examination of arrested person by medical practitioner

This provision concerns medical examination of an arrested person by a registered medical practitioner and provides an additional procedural framework for such examination.

Section 349 – Power to order specimen signatures or handwriting

A Magistrate may order a person to provide specimen signatures or handwriting for investigation or proceedings.

Although this provision principally concerns identification specimens rather than DNA, it demonstrates the wider statutory framework for obtaining scientific comparison material.

D. Bharatiya Sakshya Adhiniyam, 2023 (BSA)

The Bharatiya Sakshya Adhiniyam, 2023 governs the admissibility and evaluation of evidence in criminal proceedings.

Section 39 – Opinions of experts

Section 39 makes expert opinions relevant when the Court must form an opinion on scientific questions or other specialised matters.

DNA experts, forensic scientists and laboratory specialists may provide expert opinions concerning:

DNA profiling.

Genetic comparisons.

Biological identification.

Interpretation of laboratory results.

Scientific limitations of DNA testing.

The Court must evaluate the expert opinion rather than automatically accepting it as conclusive proof.

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Section 45 – Evidence as to character or previous conduct

This is not the governing provision for DNA expert opinion under the new BSA. The relevant expert-opinion provision is Section 39.

Important transitional point: For proceedings governed by the earlier Indian Evidence Act, 1872, Section 45 was the corresponding expert-opinion provision.

4. Procedure for genetic testing during criminal investigation

A lawful and scientifically reliable DNA investigation ordinarily requires several stages.

Identification of biological evidence

Investigators identify possible biological material at the crime scene, on clothing, weapons, vehicles or other relevant objects.

Collection of samples

Trained personnel collect samples using appropriate protective equipment and contamination-control procedures.

Documentation

Investigators document the location, condition, date, time and circumstances of collection.

Sealing and labelling

Samples are separately packaged, labelled and sealed to prevent contamination or substitution.

Chain of custody

Every transfer of evidence must be documented, including the identity of the person handling it.

Laboratory examination

A qualified forensic laboratory extracts DNA and develops a genetic profile using appropriate validated procedures.

Comparison and interpretation

The crime-scene profile is compared with the reference sample and the scientist evaluates the statistical significance of any match.

Preparation of forensic report

The laboratory prepares a report explaining the methodology, results, limitations and conclusions.

Judicial examination

The Court considers the DNA report together with the chain of custody, expert testimony and other evidence.

5. Major legal principles governing crime investigation genetic testing

A. Principle of informed consent and lawful compulsion

Consent is an important safeguard in genetic testing, especially where samples are collected from victims, witnesses or persons who are not legally required to provide them.

However, consent is not an absolute requirement in every criminal investigation.

Where legislation authorises compulsory collection, the investigating authority must satisfy the statutory conditions.

A DNA examination must not become a method of arbitrary bodily intrusion.

B. Principle against self-incrimination

The Constitution distinguishes between compelled testimonial communication and the collection of physical evidence.

A DNA sample is ordinarily physical evidence. Its collection does not automatically violate Article 20(3).

However, involuntary investigative techniques that extract testimonial responses may violate constitutional protections.

C. Principle of scientific reliability

A DNA match is not automatically proof of criminal guilt.

Courts must consider:

Accuracy of the laboratory method.

Possibility of contamination.

Quality of the biological sample.

Possibility of mixed DNA profiles.

Statistical interpretation.

Laboratory errors.

Alternative explanations for the presence of DNA.

D. Principle of chain of custody

The prosecution must establish that the biological material tested by the laboratory is the same material collected during the investigation.

An unexplained break in the chain of custody may seriously weaken the evidentiary value of the DNA report.

E. Principle of proportionality and privacy

Genetic testing should be limited to legitimate investigative objectives.

The collection, storage, comparison and disclosure of genetic information should not extend beyond what the applicable law permits.

F. Principle of fair trial

The accused must have a meaningful opportunity to examine and challenge the forensic evidence relied upon by the prosecution.

This includes access, subject to applicable legal procedures, to relevant laboratory documentation and the opportunity to question the expert.

6. Important Supreme Court judgments on genetic testing

1. Selvi v. State of Karnataka (2010) 7 SCC 263

Leading constitutional authority

Facts:

The Supreme Court considered the constitutional validity of involuntary administration of:

Narcoanalysis.

Polygraph examinations.

Brain Electrical Activation Profile (BEAP) tests.

The issue concerned the right against self-incrimination under Article 20(3) and personal liberty under Article 21.

Judgment:

The Supreme Court held that the involuntary administration of these techniques violates constitutional protections.

Importantly, the Court distinguished DNA samples from testimonial statements.

It explained that collecting and retaining DNA samples, being physical evidence, does not ordinarily encounter the same Article 20(3) constitutional obstacle as compelled testimonial responses.

Legal principles:

Physical evidence is distinguishable from testimonial evidence.

Compelled testimonial responses receive constitutional protection.

DNA profiling can serve identification and comparison purposes.

Scientific investigation must respect personal liberty.

Importance: This judgment provides the constitutional foundation for distinguishing compulsory DNA collection from prohibited testimonial compulsion.

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2. Santosh Kumar Singh v. State through CBI (2010) 9 SCC 747

Facts:

The case concerned the rape and murder of Priyadarshini Mattoo.

DNA examination was used to connect biological material recovered during the investigation with the accused.

Judgment:

The Supreme Court accepted the DNA evidence and approved the High Court's conclusions concerning its evidentiary value.

The Court considered the forensic expert evidence and the scientific examination undertaken.

Legal principles:

DNA evidence can provide powerful corroboration.

Expert testimony must be properly evaluated.

Courts should not reject scientific evidence without a proper evidentiary basis.

The defence must have an opportunity to challenge the forensic findings.

Importance: The judgment demonstrates how genetic testing can play a significant role in proving sexual offences and identifying perpetrators.

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3. Dharam Deo Yadav v. State of Uttar Pradesh (2014) 5 SCC 509

Facts:

The case concerned the murder of a foreign national. Her skeletal remains were recovered, and scientific testing, including DNA examination, was used to establish identity.

Judgment:

The Supreme Court considered DNA evidence along with other circumstantial evidence.

The scientific examination helped establish the identity of the deceased.

Legal principles:

DNA examination is an important forensic identification technique.

Scientific evidence can support circumstantial evidence.

DNA evidence must be evaluated in the context of the entire prosecution case.

Scientific investigation can assist in identifying unidentified human remains.

Importance: This decision is particularly relevant to missing-person investigations, murder investigations and identification of skeletal remains.

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4. Pattu Rajan v. State of Tamil Nadu (2019) 4 SCC 771

Facts and legal issue:

The Supreme Court examined the evidentiary value of scientific and expert opinion in criminal proceedings.

Judgment:

The Court explained that DNA evidence, like other expert opinion, is not infallible.

Its probative value depends on the circumstances of the individual case and the other evidence available.

Legal principles:

DNA evidence is opinion evidence.

Scientific accuracy does not mean absolute infallibility.

A DNA match must be evaluated alongside other evidence.

The absence of DNA evidence does not automatically justify an adverse inference.

Importance: This judgment prevents courts from treating DNA results as unquestionable proof of guilt.

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5. Manoj v. State of Madhya Pradesh (2023) 2 SCC 353

Facts:

The case involved a criminal prosecution in which the Supreme Court examined the quality and reliability of scientific evidence, including DNA testing.

Judgment:

The Court emphasised the need for proper forensic procedures, quality control and safeguards against contamination.

It highlighted the importance of reliable collection, preservation and examination of biological evidence.

Legal principles:

DNA testing must be scientifically reliable.

Proper chain of custody is essential.

The possibility of contamination must be addressed.

Forensic reports should be scrutinised rather than accepted mechanically.

Courts should examine the methodology and evidentiary foundation of DNA results.

Importance: This is a particularly significant authority on forensic accountability and the reliability of DNA evidence in Indian criminal trials.

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7. Additional judicial authorities relevant to genetic testing

A. Justice K.S. Puttaswamy v. Union of India (2017) 10 SCC 1

Facts: The Supreme Court considered whether privacy is a constitutionally protected fundamental right.

Judgment: A nine-judge Constitution Bench recognised privacy as a fundamental right under Article 21 and other freedoms in Part III of the Constitution.

Application to genetic testing:

Genetic information can reveal highly personal information about an individual and their biological relatives.

Therefore:

Genetic data collection requires a lawful basis.

Its use must pursue a legitimate purpose.

Intrusion must be necessary and proportionate.

Unjustified disclosure and misuse may violate privacy.

Importance: This judgment provides the constitutional foundation for privacy protections in criminal genetic investigations.

B. State of Bombay v. Kathi Kalu Oghad AIR 1961 SC 1808

Facts: The Supreme Court examined whether obtaining specimen handwriting and fingerprints from an accused person amounted to compelling that person to be a witness against himself.

Judgment: The Court distinguished physical identification evidence from testimonial evidence.

Application: DNA samples, when used as physical identification material, generally fall outside the prohibition under Article 20(3).

Importance: This judgment provides an important constitutional foundation for the later distinction explained in Selvi.

C. Sharda v. Dharmpal (2003) 4 SCC 493

Facts: The Court considered whether a court could direct a medical examination of a party in matrimonial proceedings.

Judgment: The Supreme Court recognised that a court may, in appropriate circumstances and under lawful authority, direct medical examination.

However, such orders must be justified by the circumstances and cannot be issued arbitrarily.

Application: The judgment is relevant to the balancing of bodily privacy and legitimate judicial requirements for scientific examination.

D. Manu Sharma v. State (NCT of Delhi) (2010) 6 SCC 1

Legal relevance: The decision addresses fair-trial requirements and the importance of disclosure of relevant material.

Its principles are relevant when an accused seeks access to material necessary to challenge the prosecution's forensic evidence.

The accused should receive a meaningful opportunity to contest evidence relied upon for conviction.

8. Legal safeguards for victims, suspects and accused persons

Crime investigation genetic testing must protect the rights of different categories of persons.

A. Protection against genetic discrimination

Genetic information must not be misused to discriminate against individuals in employment, insurance, education or other social activities.

B. Confidentiality of genetic records

Investigating authorities should restrict access to genetic information to authorised persons and legitimate investigative purposes.

C. Protection against wrongful identification

A genetic match should not be treated as sufficient proof of guilt without examining the reliability of the collection, testing and interpretation process.

D. Protection of children

DNA collection involving children requires particular attention to legal authority, parental or guardian involvement where applicable, best interests and confidentiality.

E. Protection against secondary use

Genetic information collected for one criminal investigation should not automatically be used for unrelated purposes without appropriate legal authority.

9. Major legal challenges in crime investigation genetic testing

1. Unlawful collection of DNA samples

Collection without proper legal authority may create constitutional and procedural challenges.

2. Contamination of biological evidence

Improper handling can produce misleading results or undermine the reliability of the prosecution's case.

3. DNA database privacy

Large-scale retention of DNA profiles raises questions concerning privacy, surveillance and the possibility of misuse.

4. Familial DNA searching

A DNA profile may indirectly identify biological relatives who have never been suspects in a criminal investigation.

This creates difficult questions about third-party privacy and proportionality.

5. False or misleading DNA matches

A statistical match does not necessarily establish when, how or why biological material came into contact with an object or crime scene.

6. Mixed DNA profiles

Samples containing biological material from multiple individuals can create interpretation difficulties.

7. Laboratory accountability

Errors in extraction, amplification, interpretation, documentation and reporting can undermine forensic reliability.

8. Delayed forensic examination

Delays can result in deterioration of biological evidence and difficulties in completing investigations.

9. Disclosure of laboratory documentation

Failure to provide relevant laboratory records can prevent the accused from effectively challenging forensic findings.

10. Long-term storage of genetic information

The 75-year retention framework under the Criminal Procedure (Identification) Act, 2022, raises questions about necessity, proportionality and the protection of people who are subsequently acquitted or discharged.

The statutory deletion provisions and applicable exceptions must therefore be carefully observed.

10. Evidentiary limitations of DNA testing

The legal significance of DNA testing must be understood through the distinction between a scientific match and proof of criminal responsibility.

Important principle: DNA evidence can be highly probative, but it does not independently establish every element of a criminal offence.

11. Important recent Supreme Court judgment

Irfan alias Bhayu Mevati v. State of Madhya Pradesh (2025 INSC 150, decided 16 January 2025)

Important recent authority

Facts:

The case involved the conviction of two accused persons in a serious sexual assault case involving a child. DNA evidence was a major part of the prosecution case.

The accused challenged the reliability of the DNA report and requested access to complete laboratory documentation and examination of the forensic experts.

Issues before the Supreme Court:

Whether the accused had received adequate access to DNA laboratory records.

Whether the DNA experts should be examined.

Whether the accused could meaningfully challenge the forensic methodology.

Whether reliance on an inadequately tested DNA report violated the right to a fair trial.

Judgment:

The Supreme Court allowed the application and directed that the scientific experts involved in preparing the DNA report be summoned with supporting laboratory documentation.

The Court ordered a fresh trial process with appropriate opportunities for examination and cross-examination.

It also set aside the earlier conviction and High Court judgment.

Important legal principles:

A DNA report cannot be treated as unquestionable scientific truth.

Mere exhibition of a DNA report does not necessarily prove its contents.

The accused must receive meaningful access to relevant laboratory documentation.

Chain-of-custody records are important.

Scientific experts must be available for examination where necessary to establish the reliability of the evidence.

A fair trial under Article 21 requires a genuine opportunity to challenge forensic evidence.

Importance: This judgment is particularly significant because it establishes the importance of laboratory transparency, expert accountability and meaningful defence access in DNA-based criminal prosecutions.

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12. International legal perspective

Genetic testing in criminal investigations is also regulated through international human-rights principles.

These instruments provide important standards for evaluating the legitimacy and proportionality of criminal genetic investigations.

13. Recommendations for improving India's genetic-testing framework

The following reforms could strengthen the legal framework:

1. Independent forensic oversight: Establish effective independent monitoring of forensic laboratories.

2. Clear consent standards: Clarify when consent is necessary and when compulsory collection is legally authorised.

3. Strict chain-of-custody procedures: Introduce uniform documentation and tracking systems.

4. Laboratory accreditation: Strengthen accreditation, proficiency testing and quality-control requirements.

5. DNA database safeguards: Establish clear rules concerning access, retention, correction and destruction of genetic records.

6. Protection against genetic discrimination: Prevent unauthorised use of genetic information for discriminatory purposes.

7. Defence access: Ensure access to laboratory notes, raw data, electropherograms and relevant testing documentation.

8. Protection of children and victims: Strengthen confidentiality and privacy safeguards.

9. Independent review: Provide procedures for reviewing disputed or scientifically questionable DNA results.

10. Judicial training: Improve judicial understanding of statistical interpretation, mixed DNA profiles, contamination and forensic limitations.

14. Conclusion

Crime investigation genetic testing is an essential component of modern forensic criminal justice. DNA profiling can assist in identifying suspects, establishing the identity of victims, investigating sexual offences, solving murder cases and identifying unidentified human remains.

However, the scientific usefulness of DNA evidence must be balanced against constitutional rights, personal privacy, bodily autonomy and the right to a fair trial.

The Indian legal framework consists principally of the Criminal Procedure (Identification) Act, 2022, the Criminal Procedure (Identification) Rules, 2022, the Bharatiya Nagarik Suraksha Sanhita, 2023 and the Bharatiya Sakshya Adhiniyam, 2023.

The Supreme Court decisions in Selvi, Santosh Kumar Singh, Dharam Deo Yadav, Pattu Rajan, Manoj and Irfan alias Bhayu Mevati establish important principles concerning the legality, reliability and evidentiary value of genetic testing.

The fundamental legal position is that DNA testing is a powerful investigative instrument, but scientific evidence must remain subject to constitutional safeguards, transparent forensic procedures and independent judicial scrutiny.

15. Important case-law revision table

Most important judgments for academic examination: Selvi (2010), Pattu Rajan (2019), Manoj (2023), and Irfan alias Bhayu Mevati (2025).

These cases collectively provide a strong foundation for studying the constitutional, procedural and evidentiary dimensions of genetic testing in criminal investigations.