Bombay HC: What is importance of rule of chain of custody while appreciating DNA Evidence?

[VI] In Ananda Vs. The State of Maharashtra; MANU/MH/3781/2024 : 2024:BHC-AUG:11669-DB, one of the evidence was in the nature of DNA reports and it is observed as under :

"39. The question is, based on the DNA reports, whether the conviction and/or sentence passed by the trial court would be sustainable. We have gone through the impugned judgment. The trial court has relied on the evidence of each and every witness. It also relied on the evidence of the medical officer who collected blood of the appellant for DNA analysis, even in breach of protocol in that regard. The reason assigned for relying on the said evidence is that the said witness is uninterested and independent one. Before appreciating the evidence relating to DNA, we must have a look at the guidelines for collection, storage and transportation of the crime- scene DNA samples. Those have been placed on record by learned counsel for the appellant. Item No.10 therein speaks of maintaining the chain of custody. It describes what chain of custody means. Same reads as under:-

10. Maintaining the chain of custody:

• Chain of custody is a process used to maintain and document the chronological history of the evidence.

• A `chain of custody' document should be maintained which should include name or initials of the individual collecting the evidence, each person or entity subsequently having custody of it, dated the items were collected or transferred, agency and case number, victim's or suspect's name and the brief description of the item.

Those were the guidelines issued by The Central Forensic Science Laboratory, Chandigarh. PW 18 Vaishali admitted in cross-examination that the C.FS.L., Chandigarh and Hyderabad are best in India."

18. The relevant observations from the judgment in Kattavellai @ Devakar (supra) are reproduced as under :

DNA- A NECISSITATED ADDENDUM:

43. As we have discussed earlier in this judgment, the DNA evidence collected has been rendered unusable. It suffers from various shortcomings in as much as there is large amount of unexplained delay; the chain of custody cannot be established; possibility of contamination cannot be ruled out etc. 

44. This lack of a common procedure to be followed, is concerning. As such, we issue the following directions which shall be followed henceforth, in all cases where DNA Evidence is involved:

1. The collection of DNA samples once made after due care and compliance of all necessary procedure including swift and appropriate packaging including a) FIR number and date; b) Section and the statute involved therein; c) details of I.O., Police station; and d) requisite serial number shall be duly documented. The document recording the collection shall have the signatures and designations of the medical professional present, the investigating officer and independent witnesses. Here only we may clarify that the absence of independent witnesses shall not be taken to be compromising to the collection of such evidence, but the efforts made to join such witnesses and the eventual inability to do so shall be duly put down in record.

2. The Investigating Officer shall be responsible for the transportation of the DNA evidence to the concerned police station or the hospital concerned, as the case may be. He shall also be responsible for ensuring that the samples so taken reach the concerned forensic science laboratory with dispatch and in any case not later than 48- hours from the time of collection. Should any extraneous circumstance present itself and the 48-hours timeline cannot be complied with, the reason for the delay shall be duly recorded in the case diary. Throughout, the requisite efforts be made to preserve the samples as per the requirement corresponding to the nature of the sample taken.

3. In the time that the DNA samples are stored pending trial appeal etc., no package shall be opened, altered or resealed without express authorisation of the Trial Court acting upon a statement of a duly qualified and experienced medical professional to the effect that the same shall not have a negative impact on the sanctity of the evidence and with the Court being assured that such a step is necessary for proper and just outcome of the Investigation/Trial.

4. Right from the point of collection to the logical end, i.e., conviction or acquittal of the accused, a Chain of Custody Register shall be maintained wherein each and every movement of the evidence shall be recorded with counter sign at each end thereof stating also the reason therefor. This Chain of Custody Register shall necessarily be appended as part of the Trial Court record. Failure to maintain the same shall render the I.O. responsible for explaining such lapse.

The Directors General of Police of all the States shall prepare sample forms of the Chain of Custody Register and all other documentation directed above and ensure its dispatch to all districts with necessary instruction as may be required.

 IN THE HIGH COURT OF BOMBAY (AURANGABAD BENCH)

Criminal Appeal No. 821 of 2022, Criminal Application No. 3125 of 2025 in Criminal Appeal No. 821 of 2022

Ganesh Vs. The State of Maharashtra and Ors.

Hon'ble Judges/Coram:

Neeraj P. Dhote, J.

Decided On: 13.10.2025

Citation: 2025:BHC-AUG:28711,MANU/MH/6676/2025.

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Karnataka HC: Whether Session court can convict accused under Pocso Act if DNA test comes positive even though Victim has turned hostile?

As per Ex.P33, PW.22 stated that the victim is the biological mother and accused is the biological father of the baby born to the victim. However, PW.12-victim, her grandmother, father and other relatives, unequivocally deposed that the accused did not commit any sexual act on the victim. In such circumstance, the oral testimony of victim and her relatives goes contrary to the medical evidence. No doubt, evidentiary value can be attached to the DNA report issued by the expert as per Section 45 of the Indian Evidence Act. However, if the same does not corroborate the testimony of victim, in such circumstance, the Court has to test the veracity of the report based on facts and evidence of the case on hand.

16. Thus, applying the findings of the Hon'ble Apex Court and the Co-ordinate Bench stated supra to the facts and circumstances of this case, except the DNA report, absolutely no other corroborative piece of evidence is available on record to connect the accused with the alleged offence. The victim herself firmly stated that the accused did not have any sexual intercourse with her. She is not aware who the father of her child is. Even her parents and relatives also deposed similarly. In such circumstance, the DNA report cannot be solely relied to convict the accused since as per the survey and study of National Forensic Science Laboratory (NFSL) in India and as per the report of International Journal of Indian Science and Research (E-ISSN 2584-0924) published in JLFJ Volume:1, Issue:1, July 2022, the legal stands on DNA profiling considered, STR (short Tandem Repeat) testing is highly reliable method for human identification in Forensic Science and it is not strictly 100% accurate in India or globally.

 IN THE HIGH COURT OF KARNATAKA (DHARWAD BENCH)

Criminal Appeal No. 100570 of 2022 (A)

Decided On: 10.07.2025

State of Karnataka Vs. Nagesh

Hon'ble Judges/Coram:

Nataraj Rangaswamy and Rajesh Rai Kallangala, JJ.

Author: Rajesh Rai Kallangala, J.

Citation:  MANU/KA/2295/2025.

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How to appreciate DNA evidence?

 DNA evidence constitutes opinion evidence as contemplated under Section 45 of the Indian Evidence Act, and like any other opinion evidence, its probative value varies from case to case. The courts must evaluate DNA evidence with appropriate scrutiny while considering its scientific foundation and procedural compliance.

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Beyond the Double Helix: Supreme Court's Emphasis on Random Match Probability and Chain of Custody in DNA Evidence Analysis

 In the case of Manoj v. State of Madhya Pradesh (2022) , the Supreme Court of India emphasized significant concerns surrounding the trustworthiness of DNA evidence, specifically the potential for contamination. The Court determined that the lack of a random occurrence ratio in the DNA analysis could give rise to substantial uncertainties regarding the precision and dependability of the evidence. The significance of this ratio is in its ability to offer a statistical indication of the likelihood of encountering a specific DNA profile within the overall population. The credibility of the DNA evidence is impaired if we do not take into account the 'random match probability', which measures the possibility of a DNA profile randomly matching someone other than the suspect. The Court emphasized the need of including this statistical probability in order to build a strong and scientifically valid foundation for DNA matches. This ensures that the evidence can withstand scrutiny and serve as a dependable basis for judicial decisions.

 IN THE SUPREME COURT OF INDIA

Criminal Appeal Nos. 248-250 of 2015

Decided On: 20.05.2022

Manoj and Ors. Vs. State of Madhya Pradesh

Hon'ble Judges/Coram:

U.U. Lalit, S. Ravindra Bhat and Bela M. Trivedi, JJ.

Author: S. Ravindra Bhat, J.

Citation: MANU/SC/0711/2022.

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Supreme Court: From Crime Scene to Courtroom: DNA Evidence Collection, Analysis and Legal Requirements

 DNA evidence constitutes opinion evidence as contemplated under Section 45 of the Indian Evidence Act, and like any other opinion evidence, its probative value varies from case to case. The courts must evaluate DNA evidence with appropriate scrutiny while considering its scientific foundation and procedural compliance.

DNA Profiling: Scientific Methodology and Process

Nature of DNA Evidence

·       DNA (Deoxyribonucleic acid) is genetic material present in cell nuclei, composed of four nucleotides: Adenine (A), Guanine (G), Thymine (T), and Cytosine (C).

·       Only 0.1% of DNA differs between individuals, with forensic scientists analyzing variable regions to generate unique DNA profiles

·       Current genetic markers of choice for forensic purposes are Short Tandem Repeats (STRs)

DNA Profiling Methodology

The DNA profiling process involves four sequential steps:

·       Isolation, purification and quantitation of DNA

·       Amplification of selected genetic markers

·       Visualizing fragments and genotyping

·       Statistical analysis and interpretation

Statistical Analysis and Interpretation Standards

Three Possible Outcomes of Profile Comparison:

·       Match: DNA profiles from two samples are indistinguishable

·       Exclusion: Profile differences indicate different biological sources

·       Inconclusive: Data insufficient for definitive conclusion

Random Match Probability (RMP): Statistical calculations must support any declared "match" by estimating the frequency of the particular DNA profile in a population.

Collection and Preservation Requirements

Legal and Scientific Prerequisites

DNA evidence must be properly documented, collected, packaged, and preserved to meet legal and scientific requirements for court admissibility. Contamination risks require heightened attention during:

·       Location and identification of biological specimens

·       Collection and packaging procedures

·       Chain of custody maintenance

·       Laboratory transmission protocols

Evidentiary Standards and Judicial Scrutiny

Quality Control Requirements

Courts have emphasized that DNA profile validity and reliability depend on quality control and quality assurance procedures in the laboratory. The mere exhibition of DNA reports without examining their underlying basis renders such evidence "highly vulnerable".

Burden of Proof Standards

·       DNA evidence may be more useful for investigation purposes than for raising presumptions of identity in court

·       Courts must examine whether DNA techniques were reliably applied by experts

·       Possibility of sample tampering during storage periods affects evidential weight

Precedential Guidelines

International Standards: Following R v. Dohoney & Adams, courts should require:

·       Scientist testimony on DNA comparisons with random occurrence ratio calculations

·       Prosecution disclosure of calculation methodologies to defense

·       Defense expert access to databases underlying the calculations

Judicial Observations: DNA testing provides "powerful new evidence unlike anything known before" and can determine biological tissue matches "with near certainty," while simultaneously serving to exonerate wrongly convicted individuals and confirm valid convictions.

Legal Principle Established

DNA evidence, while scientifically advanced and potentially conclusive, requires strict adherence to collection protocols, chain of custody procedures, and quality control standards. Courts must scrutinize both the scientific methodology employed and the procedural compliance achieved before according probative value to such evidence in criminal proceedings.

 IN THE SUPREME COURT OF INDIA

Criminal Appeal Nos. 611, 612-613 and 614-615 of 2022

Decided On: 07.11.2022

Rahul Vs. State of Delhi, Ministry of Home Affairs and Ors.

Hon'ble Judges/Coram:

U.U. Lalit, C.J.I., S. Ravindra Bhat and Bela M. Trivedi, JJ.

Author: Bela M. Trivedi, J.

 Equivalent Citations

2022 SCC ONLINE SC 1532,2023 SCC 1 83,2022 AIR SC 5661,2022 INSC 1176, MANU/SC/1455/2022

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DNA Evidence in Criminal Proceedings: Scientific Foundations and Legal Framework

 Introduction

DNA evidence has revolutionized forensic science and criminal investigations, providing unprecedented accuracy in identifying biological materials and establishing connections between suspects, victims, and crime scenes. However, the admissibility and probative value of DNA evidence in criminal proceedings requires careful judicial scrutiny of both its scientific methodology and procedural compliance.

Legal Classification: DNA as Opinion Evidence

DNA evidence constitutes opinion evidence under Section 45 of the Indian Evidence Act, and like any other opinion evidence, its probative value varies from case to case. This classification requires courts to evaluate DNA evidence with the same rigorous standards applied to expert testimony, ensuring that the scientific foundation and methodology meet established legal requirements.

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