FM12.1-6,FM14.{7,19} | Forensic Laboratory, Trace Evidence & Recent Advances — Glossary

An individual who secretes ABO blood group antigens into body fluids (saliva, semen, vaginal secretions, tears); approximately 80% of the population are secretors; allows blood grouping from non-blood forensic specimens.

A sensitive forensic method for blood group determination from small or aged stains; the stain absorbs antibody from a known antiserum; the antibody is then eluted by heating and detected with indicator cells; preferred for older or very small stains.

The quality of evidence that allows it to be received and considered by a court in legal proceedings; evidence lacking admissibility (e.g. due to broken chain of custody or biased report) cannot be used regardless of its scientific content.

The visible clumping of red blood cells caused by the cross-linking of surface antigens with their complementary antibodies; the fundamental reaction read in blood grouping.

Not applicable to this SDL; vitreous humour (posterior) is the forensically relevant specimen, not the anterior chamber.

An automatic, tamper-evident log maintained by an EMR system recording every access, modification, and deletion event with the user account, timestamp, and nature of the action; used in forensic examination to detect unauthorised or undisclosed modifications to medical records.

The legislation that replaced the Code of Criminal Procedure (CrPC) 1973 in India; governs criminal procedure including provisions for medical examination of persons in custody.

An exact, bit-for-bit copy of a storage medium, including deleted files and unallocated space; the gold standard for digital evidence acquisition; created using write-blocker hardware to preserve the original.

An EEG-based forensic technique measuring the P300 event-related potential in response to crime-specific stimuli; theoretically detects concealed crime-specific knowledge; results not admissible as evidence in India per Selvi (2010); voluntary consent required.

A sterile swab rubbed vigorously on the buccal (cheek) mucosa to collect epithelial cells carrying nuclear DNA; the standard non-invasive reference DNA sample collection method for living persons.

The continuous, documented record of possession and transfer of a forensic exhibit from the moment of collection to its presentation in court; a break in this chain renders evidence inadmissible.

Indian legislation replacing the 1986 Act that governs consumer rights and deficiencies of service; applies to healthcare, including the right of patients to access their medical records and receive services free from negligence.

The formal letter accompanying specimens dispatched to the Forensic Science Laboratory; must specify FIR details, a numbered exhibit list with specimen condition, specific tests requested with rationale, and relevant case history.

The inadvertent transfer of DNA from one person, object, or exhibit to another; can cause false inclusion of an individual in a DNA match; prevented by fresh gloves per exhibit, air-drying, and not opening multiple exhibits simultaneously.

A fixed-length string generated from a digital file by a mathematical hash function (e.g. MD5, SHA-256); any alteration to the file changes the hash completely (avalanche effect); used to verify that a digital exhibit has not been modified since its lawful acquisition.

The application of scientific methods to identify, preserve, examine, and present digital evidence (electronic records, communications, metadata) in a legally admissible form.

A colloquial term for DNA profiling; originally referred to the RFLP method introduced by Sir Alec Jeffreys in 1984; now commonly used to mean STR-based profiling.

Indian legislation proposing to establish a National DNA Database (NDNA) governed by a DNA Regulatory Board, with defined consent, privacy, and access provisions for forensic DNA use; had not received full parliamentary enactment as of the knowledge cutoff.

A purple/lavender-capped blood collection tube containing ethylenediaminetetraacetic acid (EDTA) as anticoagulant; the correct container for blood specimens intended for DNA profiling; does not interfere with DNA extraction or PCR.

A digital version of a patient's medical history created and maintained by a healthcare institution; admissible as forensic evidence when accompanied by a Section 65B certificate; subject to privacy protections under IT Act 2000 and NMC Act 2020.

A reference DNA sample from the examining doctor, paramedic, or other handler provided to the laboratory alongside case exhibits; used to identify and subtract any DNA inadvertently transferred from the handler to the exhibit during collection or examination.

A unique sequential identifier assigned to each item of forensic evidence collected in a case; used to track the item through the chain of custody and cross-reference it in FSL reports and court proceedings.

A person with specialist knowledge in a field whose opinion evidence a court may receive; distinct from a witness of fact who testifies only to personal observations.

A forensic technique of approximating a face from skeletal (skull) remains using tissue-depth tables, anatomical landmarks, and clay or digital modelling; used as an investigative lead-generation tool, not as proof of identity.

First Information Report; the police document recording the initial complaint about a cognisable offence; its number is cross-referenced on all forensic specimen labels in Indian practice.

A preservative for blood specimens intended for chemical (especially alcohol) analysis, consisting of sodium fluoride (NaF, inhibits bacterial glycolysis) and potassium oxalate (anticoagulant).

The professional principle that a forensic medical officer's findings and opinions must be recorded and expressed accurately and impartially, irrespective of the interests of the party requesting the examination; the duty runs to the court.

Government-designated laboratory that receives and analyses biological and physical evidence from crime scenes and medicolegal autopsies and issues reports used in criminal proceedings.

The active agent in formalin fixative; cross-links proteins and chemically modifies organic molecules, destroying volatile and non-volatile toxic compounds sought in toxicological analysis — hence formalin is absolutely contraindicated for chemical analysis specimens.

ABO blood grouping by testing the patient's red blood cells against known anti-A and anti-B antisera; determines which antigens are present on the RBC surface.

A treated paper card onto which a drop of blood is spotted and air-dried; the card chemically lyses cells and stabilises DNA at room temperature, allowing long-term storage and transport without a cold chain; commonly used for reference DNA samples.

A measure of skin electrical conductance reflecting eccrine (sweat gland) activity driven by sympathetic nervous system arousal; one of the physiological parameters measured in polygraph examination as a correlate of emotional arousal during questioning.

The logical conclusion drawn from an interpretation in the specific context of the case — what the scientific meaning implies about the events under investigation.

India's primary legislation governing electronic records, electronic contracts, digital signatures, and cybercrimes; amended significantly in 2008 to add provisions on privacy (Section 66E), data security (Section 43A), and data disclosure (Section 72A).

The scientific meaning of an analytical finding — what the FSL result signifies in terms of biological, chemical, or physical processes.

The principle that if an ABO antigen is present on a person's red blood cells, the corresponding antibody will be absent from their serum, and vice versa; forms the logical basis for ABO blood group determination by forward and reverse grouping.

Forensic principle attributed to Edmond Locard stating that every physical contact between two objects results in a bidirectional exchange of trace material; the foundation of trace-evidence science.

A formal medical document produced in response to a legal requisition, documenting examination findings, evidence collection, and a professional opinion intended for use in legal proceedings.

Data automatically recorded about a digital file by the creating system, including creation timestamp, last-modified timestamp, authoring user account, and system IP address; used in forensic examination to verify or challenge the claimed provenance of a digital document.

DNA present in mitochondria; maternally inherited; less discriminating than nuclear STR profiling but useful for identification of degraded specimens (hair shafts, old bone) where nuclear DNA is insufficient.

A forensic method for blood group determination from dried stains; the stain material reacts with typing antiserum, and indicator cells of known group are then added; agglutination around stain particles under microscopy indicates the presence of the specific antigen.

Forensic technique involving intravenous administration of a sub-anaesthetic dose of sodium pentothal (thiopentone) to reduce critical inhibitions and elicit verbal responses; results are not admissible as evidence in Indian courts per Selvi (2010); can only be administered with voluntary informed consent.

The National Medical Commission Act 2020, which replaced the Indian Medical Council Act 1956; governs medical education, registration, and professional conduct of medical practitioners in India, including obligations regarding patient records and confidentiality.

The forensic medical officer's professional conclusion derived from interpretation and inference, expressed in probability language and confined to the Opinion/Conclusion section of the ML report.

An electrophysiological brain response occurring approximately 300 milliseconds after a relevant or surprising stimulus, reflecting cognitive recognition; the neurological basis underlying brain mapping in forensic investigation.

A digital system for storing, retrieving, and transmitting medical imaging data (radiological and pathological images in DICOM format); PACS data can be a forensic exhibit in cases involving altered, falsified, or backdated imaging reports.

Protection of Children from Sexual Offences Act 2012; governs sexual offences against persons under 18 years of age in India; requires child-friendly examination environments and specific documentation standards.

A device that simultaneously records multiple physiological parameters (blood pressure, respiration, galvanic skin response) during questioning to assess autonomic arousal as a correlate of deception; results are not admissible as evidence in Indian courts per Selvi (2010).

Computed tomography scanning applied to a deceased body for forensic examination; provides excellent detail of skeletal injuries, fracture patterns, projectile paths, and gross organ morphology; limited for soft-tissue injury and cannot replace histopathology.

The phenomenon by which drug/toxin concentrations in post-mortem blood differ from ante-mortem concentrations due to tissue leakage, gastric re-diffusion, and microbiological activity after death; can elevate measured concentrations falsely.

Graduated terminology used in forensic medical opinions to express the degree of certainty — 'consistent with', 'probable', 'possible', 'not consistent with' — matched to the level of scientific support from the findings.

The capacity of evidence to prove or disprove a fact in issue in legal proceedings; forensic evidence with a broken chain of custody loses probative value because its integrity cannot be assured.

95% ethanol; used as a fallback preservative for viscera only when saturated NaCl is unavailable; the FSL must be informed as it may interfere with alcohol assays.

A formal written request from a legal authority (police, court, or magistrate) directing a doctor to conduct a medicolegal examination and produce a report; the medicolegal examination begins from this authority.

ABO blood grouping by testing the patient's serum against known Group A and Group B indicator cells; determines which antibodies are present in the serum; must be concordant with forward grouping.

A false-positive artefact in blood grouping in which RBCs stack in coin-like columns due to high plasma protein concentration; disperses with saline dilution and must be distinguished from true antigen-antibody agglutination.

Saturated sodium chloride (saline) solution used as the primary preservative for visceral specimens (liver, brain, kidney, stomach contents) submitted for toxicological analysis.

A formal declaration required under Section 65B of the Indian Evidence Act for electronic records to be admissible as primary evidence in Indian courts; provided by the person responsible for the computer system, attesting to the record's authenticity and the computer's proper functioning; held mandatory by the Supreme Court in Arjun Panditrao Khotkar v Kailash Kushanrao Gorantyal (2020).

Supreme Court of India ruling that compulsory administration of polygraph, narcoanalysis, or brain mapping violates Articles 20(3) and 21 of the Constitution; results of these techniques are not admissible as evidence even with voluntary consent; only voluntary administration is permitted.

The standardised documentation form for recording findings from an examination of a sexual assault survivor; includes history, physical examination findings, specimen collection details, and an opinion section.

The current standard method for forensic DNA profiling; analyses the number of repeats at multiple independent STR loci across the genome using PCR amplification and capillary electrophoresis to generate an individual's unique DNA profile.

Small quantities of physical or biological material transferred between objects or persons during contact; detectable by forensic analytical methods.

Post-mortem examination using non-invasive imaging technologies (PMCT, PMMRI, photogrammetry, post-mortem angiography) to document internal structures and injuries without conventional dissection; supplements but does not replace conventional autopsy.

The gel-like fluid in the posterior chamber of the eye; relatively protected from post-mortem redistribution and bacterial contamination, making it a valuable alternative specimen for drug and electrolyte analysis when other specimens are compromised.

A physical seal applied over the stopper/closure of a specimen container using wax and an official stamp; its integrity is the material evidence that the container has not been opened since collection.

Specialised hardware used in digital forensics to prevent any data from being written to the original storage medium during evidence acquisition; ensures the original is not modified during the copying process.