Practice with national-level exam (FACT, FACT Plus, NET, CUET, etc.) mocks, learn from structured notes, and get your doubts solved in one place.
What the IO collects at a suspected poisoning scene, how the forensic team handles vomitus, food, foils and prescriptions, and the BNSS 2023 and BSA Section 63 chain of custody that holds it in court.
A suspected poisoning scene is the only kind of death scene where the toxicology starts before the autopsy. Most of what the FSL bench will eventually analyse is collected by the investigating officer in the first hour, often before anyone knows whether the death is suicidal, accidental or homicidal. If the IO walks past a half-eaten tiffin to focus on the body, or pours formalin into a stomach-contents jar, the case is effectively over before the viscera ever reach the lab.
This topic walks through what an IO does between arrival and dispatch. The body slumped over a dinner plate, the celphos foil under the bed with a faint garlic odour, the steel tumbler with an unknown liquid, the woman brought in unconscious with a near-empty bottle of monocrotophos beside her. Each of those scenes has a different sample list, a different set of physical risks for the responder, and a different evidentiary path through BNSS 2023 and BSA Section 63 to the trial court.
The first ten minutes decide what the FSL gets.
A poisoning death rarely announces itself. The IO is summoned to a residence or a hospital ICU with a vague initial classification: sudden death, unnatural death, suspected suicide. The poisoning hypothesis usually emerges from one of a handful of physical signs that a trained first responder reads quickly.
Three scene patterns recur often enough that every IO who works rural and peri-urban India will see them inside the first year of posting.
Each of these tells the IO which samples to prioritise and which physical risks the responding team needs to manage before disturbing anything. The chain of custody starts here, not at the malkhana. The first photograph the IO takes is already an exhibit. The first conversation with the family is already a witness statement in the making. Treating the first ten minutes as administrative is the most expensive habit an IO can develop on the poisoning beat.
Six steps from arrival to dispatch.
One container per sample, every time.
The toxicology bench can only analyse what arrives in a recognisable, intact form. The IO's job is to put each suspect material into the right container with the right preservative, and to keep food samples separate from biological samples, and biological samples separate from each other.
The standard scene sample list for a suspected poisoning, in the order it tends to be collected:
The mechanics that hold up under cross-examination.
The single most preventable mistake at a poisoning scene is the wrong preservative. Formalin destroys most analytes the toxicology bench wants to look at. Polythene degrades volatile poisons. A glass jar with an ill-fitting cork lets phosphine escape on the way to Madhuban.
| Sample | Preservative | Container | Why |
|---|---|---|---|
| Vomitus, stomach contents, viscera | Saturated sodium chloride | Wide-mouthed glass jar, screw cap | NaCl inhibits putrefaction without altering most poisons. Formalin destroys alkaloids, OPs, alcohols and many drugs and is wrong for almost every toxicology sample. |
| Blood for ethanol | Sodium fluoride + potassium oxalate | Glass vial, rubber stopper | NaF stops microbial fermentation that would generate post-mortem ethanol. Oxalate prevents clotting. Critical under Section 185 Motor Vehicles Act work. |
| Blood for carbon monoxide | Sodium fluoride alone | Glass vial, rubber stopper, filled to top | NaF stabilises carboxyhaemoglobin. Filling the vial to the top minimises headspace where CO can off-gas. |
| Whole blood for drug screening |
The chain only matters at trial.
Sealed packets travel from the police station malkhana to the FSL by official courier or by an authorised constable, accompanied by the Form 65 BNSS forwarding memo and the relevant FSL form annexures. The dispatch window most state FSLs work to is 48 to 72 hours from seizure. Anything longer becomes a chain-of-custody gap the defence will press.
State workflows vary in routing but converge on the documentation. A poisoning case from rural Sonipat goes to FSL Sector 14 Madhuban in Haryana. A case from Mumbai's western suburbs goes to FSL Kalina. A Chandigarh case lands at CFSL Sector 36. A Hyderabad city case goes to FSL Rasayan Bhavan at Red Hills. Each of those labs has its own intake form, its own malkhana register and its own deposit-slip format, and the IO is expected to know the local version.
Once the FSL completes the analysis, the report is forwarded to the IO under cover of a certificate. Under BSA Section 63, the certificate is what makes the FSL's electronically generated report admissible at trial. The certificate identifies the device, the analyst, the date range of the analysis and the integrity of the record. The chain of custody documentation accompanies the certificate; if the chain is broken at any link, the certificate cannot rescue the report.
The leading authority on the certificate requirement is Arjun Pandit Rao Khotkar v Kailash Kushanrao Gorantyal (2020), decided by a three-judge bench of the Supreme Court. Khotkar held that the Section 65B certificate (now Section 63 BSA) is a mandatory pre-condition to admissibility of electronic records, and that oral testimony of the analyst cannot substitute for the certificate. For toxicology, that means the FSL report, the chromatogram, the mass spectrum and the worksheet are admissible only if the BSA 63 certificate travels with them. An analyst stepping into the witness box without the certificate cannot fix the omission from the box.
The other provision the IO and the FSL need to know is BNSS Section 349, which governs the production of an expert witness. The defence is entitled to call the analyst and to cross-examine on the worksheet, the calibration record and the chain. An IO who has prepared a clean chain has very little to defend at this point; an IO who took a shortcut on the wax seal has a long afternoon ahead.
The five most common failures, none of them rare.
The same handful of mistakes appears in the appellate record over and over. None of them are mysterious; all of them are preventable at the scene.
An IO arrives at a suspected aluminium phosphide poisoning scene and finds a crushed Celphos foil on the floor. What is the correct primary precaution before lifting the foil?
The walkthrough above is the version that holds in court. The version that loses in court is the one where the IO photographs after moving the body, signs the seizure list before the panchas arrive, or pours everything into a single jar because there was only one jar in the kit. Each of those shortcuts feels minor at 0800 in a tense farmhouse; each becomes the central exhibit of a defence appeal eighteen months later. The cleanest mental model for the IO is that every shortcut taken at the scene becomes a question the analyst will not be able to answer from the witness box, no matter how strong the analytical result on paper.
| Plain EDTA (purple top) |
| Vacutainer or glass vial |
| EDTA preserves the blood for routine drug panels without interfering with HPLC or LC-MS/MS work. |
| Urine | None if frozen; 1% NaF if not | Plastic urine container, screw cap | Most drugs and metabolites are stable in frozen urine. Where freezing is not available before dispatch, NaF buys 48-72 hours. |
| Suspected phosphide foil or residue | None; airtight glass | Glass vial with PTFE-lined screw cap, sealed in a second airtight outer | Phosphine off-gasses on exposure to moisture. The double seal protects the residue and the courier. |
| Tissue for metal analysis (As, Pb, Hg) | None; rinsed and frozen | Acid-washed glass or trace-metal-clean plastic | Preservatives add their own metal background. Metal-clean containers and freezing are the only safe combination. |
The labelling on every container is what links it to the case. The standard label carries: case number, FIR number, police station, date and time of collection, IO name, sample description, weight or volume of sample, and signatures of IO, panchas and (where present) the medical officer. Each label is on the container, not on the outer packet, because the outer is often discarded at the FSL intake.
The outer packaging itself is its own document. A wide-mouthed glass jar with a screw cap, wrapped in a clean cloth or paper, tied with thread in a way that crosses the cap, sealed with melted wax at the knot, and impressed with the IO's personal seal. The seal impression is captured on the Form 65 BNSS forwarding memo at the time of sealing, not later. The packet is then cushioned with thermocol or cotton in a cardboard outer for transport.