Chain-of-Custody Defences in NDPS Trials

An NDPS prosecution ultimately depends on proving that the substance analysed by the Forensic Science Laboratory (FSL) and identified as a narcotic drug is the same substance that was recovered and seized from the accused. This link is established through the chain of custody in NDPS cases, supported by seizure records, sampling documents, seal details, malkhana entries, forwarding documents and the FSL report.

The chain of custody under the NDPS Act is therefore more than a procedural formality. Any unexplained gap, discrepancy in weight, missing record or seal irregularity can raise a question about the identity and integrity of the seized contraband. Since the prosecution’s presumptions, quantity classification, bail consequences and sentence depend on the substance being properly identified and connected to the accused, defects in the chain of custody can strike at the foundation of the NDPS case.

The Journey the Sample Takes

Between recovery and analysis, a seized substance passes through a sequence of hands and locations, each of which should generate a record:

Seizure, recorded in the panchnama and seizure memo, with the substance described, weighed and packaged.

Sampling, drawn in accordance with the applicable standing instructions, marked and sealed at the time of drawing, with the seal described in the panchnama.

Specimen seal, prepared and forwarded separately so the laboratory can verify that the seal on the sample matches.

Deposit in the malkhana, the police or agency storehouse, recorded in the malkhana register with an entry identifying the case, the article, the seal and the date.

Despatch to the laboratory, under a forwarding memo or road certificate, carried by an identified person.

Receipt at the laboratory, recorded with the condition of the seals.

Analysis, and the report.

Certification and disposal under Section 52A, which provides for the manner in which seized narcotic drugs are to be dealt with — including the drawing of samples in the presence of a Magistrate, certification of the correctness of the inventory and samples, and disposal of the bulk. A certified inventory, photographs and samples are admissible in evidence in place of the actual substance in the circumstances the section provides.

Each link should be documented, and each document should be consistent with the others.

What Defence Counsel Actually Looks for?

The NDPS chain of custody should be examined comparatively rather than argued in the abstract. A practical defence approach is to compare the seizure memo, sampling records, malkhana register, forwarding memo and FSL report and identify any discrepancies in the substance description, weight, seals, dates, package numbers or custody records.

Description of the substance. Does the seizure memo describe what the FSL report analysed?

Weight. The weight recorded at seizure, the weight of the sample drawn, the weight received by the laboratory, and the weight recorded in the report. Discrepancies here go directly to the quantity band, and therefore to Section 37 and to sentence.

Number of packages. Whether the seizure comprised one package or several, and whether the sampling reflected that.

Marks and seals. Whether the seal impression described in the panchnama matches the specimen seal, and whether the laboratory recorded the seals as intact and tallying on receipt.

Dates and times. When the substance was seized, when sampled, when deposited, when despatched, when received. An unexplained gap between seizure and deposit, or between deposit and despatch, is among the most common and most effective points.

Identity of the custodian. Who held the article at each stage, and whether the malkhana register bears the corresponding entries.

Common Chain-of-Custody Defects in NDPS Cases

Delay in despatch. A sample seized on one date and sent to the laboratory weeks later, with no explanation and no malkhana record covering the interval.

Missing malkhana entries, or entries that do not correspond to the case number or the description.

Seal discrepancies. The panchnama describing one seal, the forwarding memo another, or the laboratory recording a seal that does not match the specimen.

Sampling not done at the time of seizure, but later, without the accused or independent witnesses present.

Inadequate sampling from multiple packages, where a single sample is drawn and the entire consignment treated as homogeneous.

Non-compliance with Section 52A, particularly where the bulk has been disposed of and the certified inventory and samples are relied upon in its place, but the certification procedure was not followed.

Independent witnesses who do not support the seizure — a frequent occurrence, and one that shifts weight onto the documentary chain precisely when it is being attacked.

How the NDPS Chain-of-Custody Argument is Framed

The framing matters, because a chain-of-custody argument in an NDPS case that reads as a list of technicalities is easily answered.

The correct proposition is that the prosecution must prove that the substance analysed is the substance seized, and that where the record does not establish that link, the foundational fact is unproved. That has two consequences.

The presumptions do not arise. Sections 35 and 54 shift the burden only once the foundational facts are established. In Gangadhar alias Gangaram v. State of Madhya Pradesh, decided on 5 August 2020, the Supreme Court held those presumptions to be rebuttable and to leave intact the prosecution’s obligation to prove the charge beyond reasonable doubt.

The quantity classification fails. If the weight cannot be reliably attributed to the substance seized, the placement of the case in the commercial band — with its mandatory minimum and its Section 37 consequences — is unsupported.

Using it at the Bail Stage

In a commercial-quantity case, Section 37 requires the court to be satisfied that there are reasonable grounds for believing the accused is not guilty. A bail application that identifies a specific, documented inconsistency — a weight discrepancy, an unexplained gap in despatch, a seal that does not tally — gives the court concrete material on which to record that satisfaction, which general submissions cannot.

This is why the documents should be obtained early rather than at the stage of defence evidence.

Practical Guidance

Apply for the complete record, including the malkhana register extract and the forwarding memo, not merely the FSL report.

Build the comparison table before framing any application. It is the single most productive exercise in an NDPS defence.

Put the specific discrepancies to the seizing officer and the investigating officer in cross-examination, with the documents, rather than asking general questions about procedure.

Consider summoning the analyst where the condition of the seals on receipt, or the method of analysis, is genuinely in issue.

Keep the argument anchored to identity. The question is not whether every rule was followed perfectly, but whether the court can be satisfied that what was analysed is what was seized.

Where the chain holds, procedural complaints rarely succeed. Where it does not, the prosecution has not proved the fact on which everything else depends.

Legal Information Disclaimer

This article is published for general legal information and educational purposes only. It reflects the position of Indian law as researched up to 10 August 2026 and may not account for subsequent amendments, notifications, standing instructions or judicial developments. NDPS matters depend closely on the substance, the quantity, the procedure followed and the record in each case. It is not legal advice, does not take into account any individual’s particular facts or circumstances, and no advocate-client relationship arises from reading it. Readers dealing with an actual matter should obtain independent professional advice from a qualified advocate of their own choosing before acting on any information contained here. Statutory provisions, notified figures, rules and case citations referred to in this article have been compiled from published legal materials and may contain errors or omissions, and may have changed since the date stated; no representation or warranty, express or implied, is given as to their accuracy, completeness or currency, and each should be independently verified against the official text or the official record before being relied upon. No liability is accepted for any loss arising from reliance on this article.

Sources / Authorities

• Narcotic Drugs and Psychotropic Substances Act, 1985 — Sections 35, 37, 42, 50, 52, 52A, 54, 55 and 57 — India Code, https://www.indiacode.nic.in
• Gangadhar alias Gangaram v. State of Madhya Pradesh, Criminal Appeal No. 504 of 2020, decided 5 August 2020 — presumptions under Sections 35 and 54 are rebuttable; prosecution’s burden undisturbed — reference as reported; verify against the official record
• Hira Singh v. Union of India, (2020) 20 SCC 272, decided 22 April 2020 — https://indiankanoon.org/doc/128615827/
• Tofan Singh v. State of Tamil Nadu, (2021) 4 SCC 1, decided 29 October 2020 — https://indiankanoon.org/doc/143202244/
• Code of Criminal Procedure, 1973 — Section 293; Bharatiya Nagarik Suraksha Sanhita, 2023 — corresponding provision on reports of Government scientific experts
• Narcotics Control Bureau — standing instructions on drawing, sealing, storage and despatch of samples