The Kastle-Meyer test utilizes reduced phenolphthalein in an alkaline medium. In the presence of blood haemoglobin (peroxidase activity) and hydrogen peroxide, it oxidizes to pink phenolphthalein.

Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 (BSA) governs the admissibility of expert opinion regarding science, art, handwriting, or fingerprint impressions.

Takayama test utilizes a reagent composed of pyridine, glucose, and sodium hydroxide to generate salmon-pink rhombic crystals of pyridine hemochromogen.

Acid phosphatase, secreted by the prostate gland, occurs in seminal plasma in concentrations up to 400 times higher than in other bodily fluids.

STR markers consist of tandemly repeated short DNA sequences ranging from 2 to 6 base pairs (tetranucleotide repeats are most common in forensic kits).

Strychnine acts as a competitive antagonist of the inhibitory neurotransmitter glycine in the spinal cord, leading to uncontrolled spinal reflex stimulation and opisthotonos.

Marquis reagent contains 1 part formaldeyde (37-40%) mixed with 9 parts concentrated sulfuric acid, producing an immediate purple-violet chromophore with opiates.

In distant-range gunshot wounds (typically beyond 1 to 1.5 meters for handguns/rifles), unburned propellant flakes lose kinetic energy and cannot deposit on the skin or target.

The Modified Griess test detects burned and partially burned gunpowder particles containing nitrites by forming an orange-red azo dye with sulfanilic acid and alpha-naphthylamine.

A plain arch is the simplest fingerprint pattern; its friction ridges enter from one side, flow across with a gentle upward wave, exit the other side, and have zero deltas and cores.

Ninhydrin reacts with primary alpha-amino acids present in perspiration on porous substrates (such as paper) to produce the purple-coloured diketohydrindylidene-diketohydrindamine (Ruhemann's purple).

Mass Spectrometry separates ions based on their mass-to-charge (m/z) ratios. Coupled with Gas Chromatography (GC-MS), it provides definitive structural fingerprinting.

Section 63 of BSA 2023 requires a written certificate signed by a person occupying an official position in relation to the management of the relevant activities or lawful custody of the computer.

SHA-256 (Secure Hash Algorithm 256-bit) generates a unique 64-character hexadecimal digest. Any 1-bit alteration in digital exhibits changes the entire hash.

Algor mortis is the progressive decrease in body temperature following cessation of metabolic thermogenesis, governed by Newton's law of cooling.

Diatoms are unicellular algae with silica cell walls. In drowning, water enters lungs and diatoms penetrate alveolar capillaries into systemic circulation and bone marrow.

Cyanide produces a bitter almond odour recognizable in gastric contents and brain tissue, inhibiting cytochrome c oxidase and halting cellular respiration.

The cortex is the main body of the hair shaft and contains spindle-shaped cortical cells embedded with pigment granules (eumelanin and pheomelanin).

MDMA is 3,4-methylenedioxymethamphetamine, a synthetic entactogen and amphetamine derivative listed under the NDPS Act, 1985.

Oblique (side-angle) lighting casts shadows across microscopic depressions on paper sheets, revealing indented writing impressions left from overlying pages.

ESDA applies an electrostatic charge across a document covered with mylar film; toner particles adhere preferentially to areas with microscopic paper surface damage caused by pressure.

Birefringence is the optical property of having refractive index dependent on polarization and propagation direction of light, characteristic of crystalline and synthetic polymer fibers.

Retention time (tR) is the time required for a particular solute to elute through the column from injection to detection, serving as a characteristic qualitative identifier.

The Florence test uses Florence reagent (potassium iodide and iodine in water) to react with choline present in seminal fluid, forming dark brown rhombic choline periodide crystals.

Human saliva contains exceptionally high levels of alpha-amylase (salivary isoenzyme HSA), which digests starch into maltose and is screened via Phadebas or iodine starch assays.

Chronic arsenic toxicity causes Aldrich-Mees lines (transverse white bands on nails), raindrop pigmentation, and palmoplantar hyperkeratosis due to high affinity for keratin sulfhydryl groups.

Carbon monoxide binds to hemoglobin with an affinity >200 times higher than oxygen, forming carboxyhemoglobin which imparts a characteristic bright cherry-red color to blood and tissues.

Rifling consists of helical grooves cut into the bore of a firearm barrel, imparting gyroscopic spin to the bullet for aerodynamic flight stability.

Striated tool marks occur when a tool slides across an object (e.g. pry bar or screwdriver scrape), creating parallel minute scratch patterns unique to microscopic tool defects.

Section 66 of the IT Act penalizes computer-related offences (including hacking and fraudulent data manipulation) with imprisonment up to 3 years or fine up to 5 lakh rupees.

The anagen phase is the active hair growth period lasting 2 to 7 years. Pulled anagen hairs contain a rich follicular tag of nucleated cells optimal for nuclear DNA typing.

Crossover electrophoresis drives antigen (negatively charged) and antibody (moving by electroendosmosis) towards each other in an electric field, forming a precipitin line at origin.

Approximately 90-95% of ingested ethanol is metabolized in hepatocytes of the liver, oxidized by alcohol dehydrogenase (ADH) into acetaldehyde.

Concentric fractures form circular fracture rings around the center of impact. Per the 3R rule, concentric fracture stress ridges form at right angles on the front (loaded) surface.

Dithiooxamide (DTO or rubeanic acid) reacts with copper residues to form a dark green to olive-black copper rubeanate complex.

In the Henry Primary Classification system, only whorl patterns receive numerical values (16, 8, 4, 2, 1) based on paired finger positions, while loops and arches receive 0.

Under the Bharatiya Nyaya Sanhita, 2023, cheating and dishonestly inducing delivery of property is governed under Section 318(4), replacing IPC Section 420.

Yellow Oleander contains powerful cardiac glycosides (thevetin A, B, and thevetoxin) that inhibit cardiac Na+/K+-ATPase pumps, causing fatal arrhythmias.

Barberio's test utilizes a saturated aqueous solution of picric acid to react with spermine, precipitating distinctive yellow needle-like crystals of spermine picrate.

Internal standards compensate for analyte loss during extraction, injection volume variations, and instrument drift, providing robust quantification.

Resolution (Rs) measures how well two adjacent chromatographic peaks are separated; a baseline resolution of Rs >= 1.5 is standard in forensic chromatography.

Calibre refers to the internal diameter of the firearm bore, measured between diametrically opposing lands (or grooves) and expressed in inches or millimeters.

Ricinus communis seeds contain ricin, a ribosome-inactivating protein (RIP) of extreme toxicity that halts cellular protein synthesis by cleaving adenine from 28S rRNA.

Abrus precatorius seeds contain abrin, an extremely potent ribosome-inactivating toxalbumin used in village crimes to prepare small dried spikes (suis) to kill cattle.

RDX is chemically cyclotrimethylenetrinitramine, also designated as cyclonite or hexogen, a military high explosive with high detonation velocity.

Clause 7.4 of ISO/IEC 17025 specifies requirements for transportation, receipt, handling, protection, storage, retention, and disposal of test items, ensuring evidence integrity.

A write blocker intercepts any write commands sent from the host computer to the evidence drive, allowing only read commands and guaranteeing forensic image integrity.

Lucknow is home to premier scientific institutions including CDRI, NBRI, IITR (Indian Institute of Toxicology Research), and CIMAP.

Loops are the most common fingerprint pattern globally (approx. 60-65%), followed by whorls (30-35%), and arches (approx. 5%).

Entrance wounds show inward inversion of skin edges with a characteristic marginal abrasion collar (contusion ring); exit wounds show outward eversion with lacerated stellate edges and absence of abrasion/tattooing.