Navigating Scientific and Technological Evidence in Criminal Justice

Science and technology have transformed how crimes are investigated and prosecuted. From DNA profiling to digital forensics, courts today regularly encounter evidence that would have seemed science fiction just a few decades ago. But this raises a critical procedural question: how does a court – staffed by legal professionals, not scientists – decide whether a particular scientific theory or technological method is reliable enough to influence a verdict? The answer lies in a set of established procedures that govern how the criminal justice system evaluates and incorporates scientific and technological evidence, with judicial notice at the center of it all.

The foundational challenge: science in a legal arena 🔗

Courts operate on rules of evidence, not peer-reviewed consensus. Yet criminal trials increasingly depend on forensic analysis, digital data, biometric identification, and expert opinion. The primary goal of using scientific evidence is to ensure that justice is administered fairly – to punish the guilty rather than the innocent. But achieving that goal demands that courts carefully screen what qualifies as reliable science.

The Indian judicial system is built on the principle Ei incumbit probatio qui dicit, non qui negat – a person is innocent unless proven guilty. The legal system promises to safeguard an innocent person even if it means letting a hundred offenders go free. Scientific evidence, when properly verified, is one of the most powerful tools for realizing this promise. When it is poorly verified, it becomes a serious threat to it.

What is judicial notice? 🔗

Judicial notice is a rule in the law of evidence that allows a fact to be introduced into evidence if the truth of that fact is so notorious or well-known, or so authoritatively attested, that it cannot reasonably be doubted. Facts admitted under judicial notice are accepted without being formally introduced by a witness or other rule of evidence.

In the context of scientific and technological evidence, judicial notice works as follows: once a particular scientific theory and its application has gained general acceptance within its relevant professional community, courts can take notice of that theory without requiring fresh proof every time it is used. This prevents the justice system from re-litigating settled science case after case.

Section 57 of the Indian Evidence Act provides that the court shall take judicial notice of certain facts. The purpose of this section is to provide that the court shall take judicial notice of those facts rather than exhaust the category of facts of which the court may, in appropriate cases, take judicial notice. Recognition of facts without formal proof is an act of expediency. This principle is vital when it comes to universally accepted forensic and scientific methods – courts do not need a fresh expert to prove that fingerprinting is reliable every single time fingerprint evidence is presented.

The general acceptance standard: where it all started 🔗

The idea that courts should accept scientific evidence only when it has earned broad acceptance in its relevant community traces back to the landmark American case Frye v. United States (1923). The Frye Standard held that an expert’s opinion is admissible if the scientific technique it relies upon is generally accepted as reliable in the relevant scientific community.

The general premise in Frye v. United States states that an expert opinion is admissible if the scientific technique on which the opinion is based is “generally accepted” as reliable in the relevant scientific community. This standard dominated legal proceedings for decades and continues to be applied in several jurisdictions today.

While Frye is a US precedent, its underlying logic – that courts should defer to the scientific community’s consensus before admitting novel evidence – resonates deeply with how Indian courts approach the judicial notice of scientific theories. Once the relevant expert community reaches a consensus that a method is reliable, courts can recognize it without requiring fresh proof in each case.

The Daubert standard: a more rigorous gatekeeping framework 🔗

In 1993, the US Supreme Court introduced a more comprehensive framework in Daubert v. Merrell Dow Pharmaceuticals, Inc. that expanded beyond just “general acceptance.” The Daubert Standard provides a systematic framework for a trial court judge to assess the reliability and relevance of expert witness testimony before it is presented to a jury. It transformed the landscape of expert testimony by placing the responsibility on trial judges to act as “gatekeepers” of scientific evidence.

Under this framework, the trial court considers the following factors to determine whether the expert’s methodology is valid: whether the technique or theory in question can be and has been tested; whether it has been subjected to publication and peer review; and whether it has attracted widespread acceptance within a relevant scientific community.

Although Daubert is a US standard, its influence on Indian judicial thinking – particularly in how courts assess novel forensic evidence – cannot be overlooked. The main goal of the Daubert Standard is to prevent the admission of “junk science” into a court. Evidence must be reliable, reproducible, and from studies conducted to sound scientific standards with reasonable error rates.

How India’s legal framework handles scientific evidence 🔗

In India, the primary legislative framework governing scientific and expert evidence is found in the Indian Evidence Act, 1872. Sections 45 to 51 of the Indian Evidence Act specify the conditions under which expert opinions are considered relevant, while Section 293 of the Code of Criminal Procedure deals with the reports of government scientific experts. This framework emphasizes the necessity of expert testimony being both relevant and competent, ensuring that scientific evidence presented in court meets established legal standards for reliability and relevance.

Under Section 45, opinions of experts on matters of foreign law, science, art, or the identity of handwriting or finger impressions are relevant. This is the core provision through which forensic scientists, medical examiners, DNA analysts, and digital forensics experts find their way into Indian courtrooms. However, in India, scientific evidence is taken only as opinion evidence and is hardly decisive. The Supreme Court of India has stated that unless there is something really defective in the medical report, the court cannot reject it. The expert’s opinion is taken as corroborative evidence, not conclusive proof.

Expert evidence is not substantive evidence; it is generally used as a piece of evidence for corroboration or for countering the veracity of oral evidence. The evidence of an expert only aids and helps the court as advisory material. In this process, the court is the expert of experts.

The role of Section 293, CrPC 🔗

Section 293 of the Code of Criminal Procedure (now corresponding provisions under the Bharatiya Nagarik Suraksha Sanhita, 2023) allows reports of government scientific experts – such as those from the Central Forensic Science Laboratory, chemical examiners, and serologists – to be used as evidence without the expert necessarily appearing in court to testify. This is a practical application of the judicial notice principle: the court essentially takes notice that reports from designated government experts carry sufficient institutional reliability to be admitted without oral testimony, unless specifically challenged.

Judicial notice and general acceptance: how they work together 🔗

The concept of judicial notice and the general acceptance standard are two sides of the same coin. Once a scientific or technological method achieves general acceptance, courts begin taking judicial notice of it as a reliable tool. This evolution happens gradually, through judicial decisions that build a body of precedent.

The Supreme Court’s judgments have had a profound impact on the use of forensic evidence. Guidelines were laid down for DNA testing in paternity disputes, which have since been applied in criminal cases as well. Each case that leverages forensic evidence serves to refine the legal principles and practices surrounding its admissibility and application.

For example, DNA profiling has emerged as a powerful forensic tool in Indian criminal investigations. The Supreme Court has recognized the value of DNA evidence in several cases, including Dharam Deo Yadav v. State of Uttar Pradesh (2014), where it acknowledged DNA testing as a sophisticated scientific technique providing accurate results. Through repeated judicial recognition, DNA testing has effectively acquired the status of generally accepted science, which means courts can now take judicial notice of the reliability of the method itself – while still requiring specific evidence on whether the protocol was correctly followed in a particular case.

The problem of junk science 🔗

Not all evidence that enters courtrooms under the label of “science” deserves that label. Junk science refers to claims or methods that mimic the appearance of scientific rigor but lack genuine empirical validity. Distinctions like “good science,” “bad science,” and “pseudo-science” began long before 1923. Some scholars used these terms to describe knowledge claims not generally accepted or not in the mainstream of knowledge. Others focus upon the purported unreliability or non-experimental nature of junk science.

Junk science was becoming a problem in the courts, leading to unjust legal outcomes, driving products off the market, preventing innovation, and more. The challenge of screening junk science from valid science remains one of the most pressing issues for judges today.

Regarding the issue of admissibility, there are many challenges before the Indian judiciary. It is not easy for the judiciary to evaluate the multifarious aspects of expert evidence that have a bearing on science or technology. Legal scholars have long been confronted with the important question of who should evaluate scientific evidence – the judge or the scientific community. If the job is completely assigned to the scientific community, it would definitely affect the traditional role of judges. At the same time, judges are not supposed to act as amateur scientists.

This tension – between judicial authority and scientific expertise – is precisely why the procedures of judicial notice and general acceptance testing are so important. They create a structured mechanism for courts to rely on scientific consensus without either surrendering their adjudicative role or pretending to expertise they don’t have.

The Bharatiya Sakshya Adhiniyam, 2023: a new legislative chapter 🔗

The Indian Evidence Act, 1872 has now been replaced by the Bharatiya Sakshya Adhiniyam (BSA), 2023, which came into force in July 2024. The BSA retains the essential structure governing expert opinion and judicial notice but introduces updated provisions that acknowledge electronic and digital evidence more explicitly. This legislative modernization reflects the judiciary’s ongoing effort to keep its evidentiary framework aligned with technological progress – precisely the kind of adaptive mechanism that judicial notice of scientific theories is meant to serve.

Why this matters for criminal justice in India 🔗

The procedures by which courts appreciate scientific and technological theories – judicial notice, general acceptance, expert testimony standards, and gatekeeping – are not abstract legal technicalities. They are the mechanisms that determine whether a DNA report can convict a murderer, whether digital surveillance data can place a suspect at a crime scene, or whether a forensic toxicology result can prove poisoning. Forensic science serves as the backbone of modern legal systems, providing a factual basis for the investigation and prosecution of crimes. Its emergence has revolutionized the criminal justice landscape, transitioning from a reliance on witness testimony to an evidence-based approach that can objectively link suspects to crimes – or exonerate the innocent.

The future of forensic science in India is likely to see a shift towards more specialized fields such as neuroforensic science. The judiciary’s openness to adopting new scientific methods, as long as they meet admissibility standards, signals a progressive trajectory for forensic science in the Indian justice system. As courts continue to encounter AI-generated evidence, predictive analytics, and cyber forensics, the frameworks of judicial notice and general acceptance will become even more critical in distinguishing reliable science from noise.

The goal, ultimately, is that expert testimony is crucial to the resolution of complicated criminal cases, but its use must be carefully considered and controlled to make sure that it advances rather than impedes the right administration of justice.

What do you think? Given that Indian judges are not trained scientists, should there be a dedicated independent body – similar to the UK’s proposed Forensic Science Advisory Council – to help courts evaluate the general acceptance and reliability of novel forensic methods before they are admitted in criminal trials? And with the rapid rise of AI-generated forensic analysis, how should the principles of judicial notice and general acceptance evolve to address evidence that no traditional “scientific community” has yet fully validated?

References

1. https://www.indiacode.nic.in/bitstream/123456789/15351/1/iea_1872.pdf
2. https://www.indiacode.nic.in