Forensic Science and the Rights of the Accused

Held, on article 21 and beyond. Compulsion also violates the substantive due process required for restraining personal liberty, and does so whether the technique is administered during an investigation or for any other purpose, since the results could expose a person to adverse consequences of a non-penal nature. The techniques cannot be read into the Explanation to sections 53, 53-A and 54 of the Code by an expansive interpretation. Compulsory administration is an unjustified intrusion into mental privacy, would amount to cruel, inhuman or degrading treatment in the language of evolving international human rights norms, and conflicts with the right to a fair trial. Invocations of a compelling public interest cannot justify diluting such rights.

The order. No individual should be forcibly subjected to any of the techniques, whether in a criminal investigation or otherwise. Room is left for voluntary administration with safeguards, but even where the subject has consented the results by themselves are not admissible, because the subject does not exercise conscious control over the responses.

The distinction that decides these cases

The reason DNA and fingerprints are treated differently from narcoanalysis is not that one is more modern or more reliable. It is the testimonial line.

The Court's reasoning on the three techniques is that each produces a result that is testimonial in character even though nothing is spoken in the ordinary way. The polygraph and the BEAP test read a bodily response, but the response is a proxy for the content of the mind, so the result conveys personal knowledge. That step is the intellectual heart of the case and is what a good answer must reproduce.

The second holding, which is often missed

Even a consenting subject's test results are not admissible by themselves. The reason given is that the subject does not exercise conscious control over the responses. That is a statement about the reliability of the technique rather than about the rights of the accused, and it matters for two reasons.

It means consent does not convert the technique into ordinary evidence, so a practice of obtaining consent from persons in custody cannot be used to get the results before a court.

And it shows the Court doing something courts are often reluctant to do: assessing the scientific claim rather than accepting it. The techniques were not excluded only because using them would be unfair; they were also found not to be what they were said to be.

DNA, and where the line now sits

DNA identification is material evidence on the distinction above, so article 20(3) is not the obstacle. The questions it raises fall elsewhere and are the questions worked in [Bodily Integrity and Intervention Without Consent] and [Privacy and Surveillance]:

• Taking the sample is an interference with bodily integrity, so it needs statutory authority and proportionality.
• Retention of the profile after acquittal is an interference with informational privacy that is not justified by the aim of solving the offence charged.
• Familial searching, partial matching to identify relatives, extends the burden to persons against whom nothing is alleged and who have not consented.
• Error and interpretation: a match is a probability, and its weight depends on the size and composition of the reference database, which is a matter about which the accused must be able to cross-examine.

Worked example

An investigating officer proposes to put a suspect through a polygraph examination and, on the strength of the result, to search a location. The suspect signs a consent form at the police station in the presence of the officer.

Was the consent free? A consent given in custody to a technique proposed by the custodian raises the freedom question directly. This is the point where the consent requirements set out in [Bodily Integrity and Intervention Without Consent] do their work, and Selvi contemplates voluntary administration only with safeguards.

If the consent was valid, may the result be used? Not by itself. Selvi is express: even where the subject has consented, the results by themselves are inadmissible, because the subject does not exercise conscious control over the responses.

May the search proceed on the result? This is the practical question and it is distinct. The prohibition on compulsory administration is absolute in the sense the Court described, and the inadmissibility of the result is a rule about evidence. Whether information derived from a lawful voluntary test may direct an investigation is a separate question from whether the test itself may be led, and an answer should keep the two apart.

And what if there had been no consent? Then nothing in it is available. Compulsory administration violates article 20(3) and substantive due process under article 21, and a compelling public interest is not an answer.

What it does NOT mean

It is not a prohibition on forensic science. DNA, fingerprints and medical examination under the Code are untouched. The case is about techniques that read the mind.

Article 20(3) is not confined to the trial. Selvi holds that its protective scope extends to the investigative stage, and that read with section 161(2) it covers suspects and witnesses as well as the accused.

"It only guides the investigation" is not an answer. The Court rejected it, holding the violation complete whether the technique is administered in an investigation or for any other purpose, since the results can expose a person to non-penal adverse consequences.

And the absence of pain is not the test. The State argued that the techniques cause no bodily harm, and the Court held that the intrusion is into mental privacy, which the absence of physical harm does not answer.

Quick revision

• The line is material versus testimonial. Material evidence exists independently of the mind and may be compelled; testimonial evidence is the product of the accused's mental process and may not.
• Selvi (2010): compulsory narcoanalysis, polygraph and BEAP violate article 20(3), whose scope reaches the investigative stage and, with section 161(2), covers accused, suspects and witnesses; the results are testimonial, not material. They also violate substantive due process under article 21, are an unjustified intrusion into mental privacy, would amount to cruel, inhuman or degrading treatment, and conflict with the right to a fair trial. A compelling public interest cannot justify dilution.
• The techniques cannot be read into the Explanation to sections 53, 53-A and 54 of the Code.
• Voluntary administration is possible with safeguards, but the results by themselves are inadmissible, because the subject does not exercise conscious control over the responses.
• ICCPR article 14(3)(g): not to be compelled to testify against oneself or to confess guilt.
• DNA is material evidence, so the issues are taking, retention, familial searching and the weight of a match, not article 20(3).

Test yourself

1. State the distinction between material and testimonial evidence and explain how the Court applied it to the polygraph. Material evidence is a physical thing obtained from the body or the scene, such as blood, hair or a fingerprint; it exists independently of the accused's mind and would exist if they were unconscious, so compelling its production does not require the accused to furnish anything from their own knowledge and article 20(3) is not engaged. Testimonial evidence is the product of the accused's own mental process and conveys personal knowledge, and it is protected. The Court applied the distinction to the polygraph by looking past the fact that what is measured is a bodily response: the response is a proxy for the content of the mind, so the result conveys personal knowledge and bears a testimonial character, which is why it cannot be categorised as material evidence.

2. How far does the protection of article 20(3) extend, on the reasoning in Selvi? Its protective scope extends to the investigative stage of criminal cases, and not merely to the trial; read with section 161(2) of the Code of Criminal Procedure 1973 it protects accused persons, suspects and witnesses examined during an investigation alike; and it protects the choice between speaking and remaining silent irrespective of whether the testimony that would result proves inculpatory or exculpatory, since the aim is to prevent the forcible conveyance of personal knowledge relevant to the facts in issue.

3. Why are the results of a voluntarily administered test still inadmissible by themselves, and what is significant about that holding? Because the subject does not exercise conscious control over the responses, so the material produced is not the product of a deliberate act of communication even where the subject agreed to undergo the procedure. It is significant for two reasons. It prevents the prohibition being circumvented by obtaining consent from persons in custody, since consent secures the lawfulness of administering the test but not the admissibility of its product. And it shows the Court evaluating the scientific claim rather than accepting it: the exclusion rests not only on the unfairness of compelling the technique but on a finding about what the technique can actually establish.

4. The State argued that the techniques cause no bodily harm and are gentler than the third degree. Why did these arguments fail? The absence of bodily harm failed because the intrusion the Court identified was into mental privacy, and the integrity protected under article 21 extends to the mind as well as the body, so a technique that touches nobody may still be an intrusion. The comparison with the third degree failed because the alternative offered is itself unlawful, and the lawfulness of a practice is not established by showing that it is preferable to torture. The Court also rejected the related submission that the techniques would merely guide the investigation, holding that the violation is complete whether they are administered during an investigation or for any other purpose, because the results can expose a person to adverse consequences of a non-penal nature.

5. Since DNA identification is material evidence, what questions does it raise and where are they answered? Article 20(3) is not the obstacle, so the questions arise elsewhere. The taking of a sample is an interference with bodily integrity and requires statutory authority and proportionality. The retention of a profile after an acquittal is an interference with informational privacy that the aim of investigating the offence charged does not justify, since that aim has been exhausted. Familial searching extends the burden to relatives against whom nothing is alleged and who have given no consent, so the interference reaches persons entirely outside the process. And the weight of a match is a probability that depends on the size and composition of the reference database, which the accused must be able to test in cross-examination if the right to a fair trial is to be real. These are questions of bodily integrity, of privacy and of fair trial rather than of self-incrimination.