With the advancement of science and technology, there has been a noticeable shift in the way criminal investigations are conducted. Conventional methods of criminal investigation have made way for scientific methods of investigation. Narco-analysis, brain mapping, polygraph, and neuro-imaging, to name a few, have revolutionized the criminal justice system's dynamics. The current study evaluates the diagnostic utility and legality of Narco-analysis and brain mapping in India. Additionally, it discusses a historic case in which the Supreme Court of India considered its importance and promulgated relevant regulations.

Finally, the Indian law of evidence offers no definitive statement regarding the admissibility of evidence gathered from Narco-analysis testing. Although a few laws convey the law's position on the technique, in this regard, an investigation will be conducted to determine whether the results of the Narco-analysis and brain mapping tests can and should be treated as definitive evidence, or whether they should be dismissed.
 
Introduction
The law is founded on the principle of justice. Criminal law, in particular, is a collection of standards for preserving social order in an ever-changing society[1]. In a democratic country such as India, the governing system is founded on the concept of 'Rule of Law,' which states that the law is supreme, that all people are equal before the law, and that justice is to be achieved through it[2].

Police investigation is the cornerstone of the Indian criminal justice system. In many cases, police officers act independently and according to their own procedures, which include resorting to third-degree tactics that are not permitted in a civil society governed by the rule of law. India has long held the belief that no form of evil can defeat evil[3]. As a result, all of this must take place within the legal framework[4]. As a bridge between science and law, it is here that we may seek scientific evidence's assistance in ensuring the successful administration of justice.

The fundamental premise guiding the use of scientific aids in investigation is the rule of fair play, an objective attitude, and an open mind throughout the gathering, analysis, and application of these scientific evidences by investigators and forensic professionals. Tests for Deception Detection are a critical scientific technique for criminal investigation. DDT techniques, such as narco-analysis and brain mapping, have profound scientific, ethical, and legal consequences.

The DDTs are advantageous for obtaining information about criminal activity. This knowledge is frequently critical for criminal investigations because it is unique to the individual[5]. Law enforcement agencies have made extensive use of DDTs. However, investigators are aware that the information gathered cannot be used in court. They argue that it is more secure than some investigators"third degree approaches.' Recently, despite a dearth of compelling data, these approaches have been marketed as more accurate and superior to all others. Investigative authorities have conducted tests in a number of high-profile cases.

These scientific methods of investigation have the potential to develop into a viable alternative to third-degree physical torture in police custody very quickly. As the Supreme Court stated in D. K. Basu v. State of West Bengal[6], scientific techniques for investigating and interrogating accused persons are necessary, as custodial deaths and torture are flagrant violations of the rule of law.

However, when the rule of law is considered in relation to the same, another issue arises in relation to certain constitutional mandates that must be analysed in context. The Supreme Court, in Selvi v. State of Karnataka[7], expressed grave reservations about involuntary brain mapping tests on the grounds that they violate the 'Right against self-incrimination' guaranteed by Article 20(3)[8] of the Constitution, which states that no person charged with an offence shall be compelled to testify against himself/herself, and the Right to life and personal liberty guaranteed by Article 21[9], which was interpreted to include Notably, an accused person may invoke article 20(3) only if and only if he is compelled to testify against himself[10].

The question is whether such technologies and tests will violate Constitutional mandates. Thus, the present article examines the extent to which human rights and constitutional mandates retain their value when scientific methodologies are used by state agencies to gather evidence and enforce the law.
 
Issues Addressed

1. Whether involuntary use of DDT techniques violates Article 20 (3) of the Constitution's prohibition on self-incrimination.
2. Whether the involuntary administration of the procedures is a reasonable restriction on personal liberty as defined in Article 21 of the Constitution.

Research Objective
In this paper, the research objective is to examine the interplay between the constitutional mandates of Articles 20(3) and 21 of the Indian Constitution, as well as the limits to which human rights and constitutional mandates can be applied in the context of scientific methodologies used by state agencies for the purpose of adducing evidence and enforcing the law.

Research Methodology
This paper's Research Methodology incorporates both doctrinal and empirical methods of research. The primary legal sources consulted for this paper include relevant case law, officially filed petitions, as well as statutes and regulations from both India and elsewhere. There have also been references to secondary sources of law, such as reports, journals, and academic articles.
 
Conclusion And Recommendations
In conclusion, DDT methods (Brain Mapping, Narco-Analysis, and Lie-detection tests) are immature in India, and their reliability is unknown. On the other hand, such procedures are critical in today's criminal investigation and are necessary for a timely and efficient investigation. The tests have come under fire on numerous occasions, and it is still unclear to what extent they can be used to exhume hidden knowledge in practical real-world scenarios.

The Supreme Court has ruled that involuntary DDT use has no place in the legal system. Rather than that, it will disrupt procedures, cause delays, and generate other issues, all of which will result in a process with no more degree of certainty than already exists. DDT formulations currently in use require extensive testing in normative and pathological populations.

Outside of research environments, these technologies should not be implemented prematurely. Furthermore, it is crucial to understand these tests' sensitivity and specificity. DDT operations should be standardized. However, in the authors' opinion, the involuntary nature of the tests should not preclude their admission during the Investigation Stage.

As in the Petlawad Blasts Case[11], where the evidence is so contradictory, such tests should be undertaken regardless of authorization, as the Criminal Justice System's prime objective is to bring the truth and serve justice to the people, not to merely close cases by reaching a judgement. Thus, there is little doubt that forensic evidence is crucial in bridging gaps in criminal investigations and assisting courts in arriving at consistent conclusions.

Thus, medical and forensic evidence should be promoted through the progress of medico-legal professionals to the level of assistance to the court. Additionally, the legislature must establish new legislation and amend the Evidence Act to make the necessary adjustments. The Information Technology Act and the Criminal Procedure Code have been updated to improve their forensic compatibility and to keep pace with modern technological breakthroughs. As a result, similar behaviors must be recreated.

End-Notes:

1. Joel. B. Grossman and Richard. S. Wells, "Constitutional Law and Judicial Policy Making", New York: John Wiley and Sons, 1972, pp 14-16.
2. C. K. Takwani, "Lectures on Administrative Law", Lucknow: Eastern Book Company, 3rd edition, 2001, pp 16-21.
3. Jitendra Mishra, "Custodial Attrocities, Human Rights and Judiciary", Journal of the Indian Law Institute, vol.47, 2005, p 510.
4. N. K. Jain, "Custodial Crimes: An Affront to Human Dignity", Human Rights Year Books, 2000, p 64.9  R.P.S.
5. Nose I, Murai J, Taira M. Disclosing concealed information on the basis of cortical activations. Neuroimage. 2009;44:1380–6
6. D. K. Basu v. State of West Bengal, AIR 1997, SC 610.
7. Selvi v. State of Karnataka, AIR 2010 SC 1974.
8. India Const., art. 20(3).
9. India Const., art. 21.
10. Dastagir v. State of Madras, AIR 1960 SC 756; RK Dalmia v. Delhi Adm., AIR 1962 SC 1821.
11. Madhya Pradesh Blasts, "Madhya Pradesh blast toll 88, gelatin stored in house could be reason", The Indian
    Express, (13th September, 2015), Retrieved from feared-dead-in-gas-cylinder-explosion-in-mp/#sthash.XTtYlDfa.dpuf>.