Criminal Investigation – Core Vocabulary

A set of 100 vocabulary flashcards covering foundational terms, procedures, forensic concepts, and specialized topics from the lecture on Criminal Investigation, crime-scene work, homicide inquiry, and sex-crime investigation.

Criminal Investigation

Systematic process of identifying, locating, and proving the guilt of an offender through the collection, preservation, and evaluation of facts.

Three-fold Aim of Investigation

1) Identify the suspect, 2) Locate the suspect, 3) Provide evidence of guilt.

Six Cardinal Points of Investigation

Essential questions: what, how, who, where, when, and why the offense was committed.

Investigator Qualities

Persevering, intelligent, incorruptible, resourceful, observant, with integrity, patience, psychological insight, imagination, and photographic memory.

Recognition (Investigative Process)

Detecting and acknowledging information or objects that relate to the crime.

Collection (Investigative Process)

Gathering all relevant information and evidence for later processing and court use.

Preservation (Investigative Process)

Protecting collected evidence from alteration, loss, or contamination.

Information (Tool of Investigation)

Organized or unorganized data obtained from people, places, or things used to identify criminals and their activities.

Interrogation

Forceful or vigorous questioning of uncooperative persons, usually suspects or associates.

Interview

Cooperative questioning of willing informants or witnesses to obtain information.

Instrumentation

Use of scientific methods and forensic technologies (e.g., ballistics, fingerprints) to detect crime and link suspect, crime, and scene.

Golden Rule in Criminal Investigation

Do not touch, alter, or remove anything at a crime scene until it is measured, sketched, and photographed.

Phase I of Investigation

Identify the suspect through confession, eyewitnesses, circumstantial or associative evidence.

Phase II of Investigation

Locate and apprehend the identified suspect.

Phase III of Investigation

Gather and present evidence that proves the accused’s guilt in court.

Fact of Existence of Crime

Element prosecutors must prove to establish that an offense actually occurred.

Elements of a Specific Crime

Legally required components that define a particular offense; must be known by the investigator.

Photographs (Recording Method)

Still images documenting scenes, evidence, and conditions for later reference and courtroom presentation.

Crime Scene Sketch

Scaled drawing showing spatial relationships of evidence and scene features.

Written Notes

Investigator’s contemporaneous narrative of observations, actions, and times at the scene.

Fingerprint Lifting

Developing and collecting latent prints from surfaces for identification purposes.

Physical Evidence

Tangible objects linking suspect, victim, and crime; collected for analysis and court presentation.

Plaster Cast

Mold made of impressions (e.g., footprints, tire tracks) for preservation and study.

Crime Scene Search

Methodical examination of a scene to locate evidence and reconstruct events.

Processing a Crime Scene

Recognizing, identifying, preserving, and collecting items of evidentiary value.

Protecting Crime Scene

Securing area and evidence against contamination, loss, or unauthorized access.

Jurisdictional Investigation

Inquiry conducted by the police unit responsible for the territory where the crime occurred.

Police Blotter

Hard-bound logbook recording all incidents, arrests, and significant events in a police station.

Team Leader (Investigation Team)

Officer who directs crime-scene activities and decisions of the investigative group.

Evidence Custodian

Team member responsible for labeling, securing, and tracking physical evidence.

First Responder

Initial officer on scene; validates incident, secures area, aids victims, and preserves evidence.

Dying Declaration

Admissible statement made by a victim believing death is imminent, describing cause or circumstances of death.

Chain of Custody

Documented, unbroken transfer of evidence from collection through analysis to courtroom.

Booking Procedure

Fingerprinting, photographing, medical exam, and record-checking of an arrested person.

Waiver (Article 125 RPC)

Signed relinquishment extending detention beyond legal period, executed in the presence of counsel.

Spot Report

Initial, brief written account of an incident submitted within 24 hours.

Case Investigation Plan (CIPLAN)

Coordinated operational blueprint for probing sensational, high-profile, or heinous crimes.

Investigator’s Notebook

Personal log where investigators record detailed case notes to refresh memory in court.

Corpus Delicti

Body or substance of the crime; proof that an offense has been committed.

Method of Operation (M.O.)

Characteristic manner in which a suspect commits a crime, useful for identification.

Somatic Death

Clinical death; complete, irreversible stoppage of respiration, circulation, and brain function.

Molecular Death

Cellular death occurring gradually after somatic death as individual cells cease function.

Apparent Death

Temporary cessation of vital signs mimicking death; also called suspended animation.

Algor Mortis

Cooling of the body after death due to halted metabolism.

Post Mortem Caloricity

Transient rise in body temperature shortly after death from rapid decomposition or internal changes.

Rigor Mortis

Post-mortem stiffening of muscles, starting 3–6 hours after death and lasting up to 36 hours.

Post Mortem Lividity (Livor Mortis)

Settling of blood in dependent body parts, causing purplish discoloration 3–6 hours post-death.

Putrefaction

Decomposition stage where tissues break down, producing gas and color changes.

Marbling

Reddish discoloration tracing superficial veins during decomposition.

Mummification

Drying and preservation of a body due to rapid dehydration in hot, dry environments.

Adipocere

Waxy, soap-like substance formed when body fat converts during decomposition in moist conditions.

Maceration

Softening of tissues in fluid without putrefaction, often seen in still-born fetuses.

Entomology of Cadaver

Study of insect activity on a body to estimate time of death.

Medicolegal Autopsy

Comprehensive post-mortem examination of a body to determine cause and manner of death for legal purposes.

Hanging

Asphyxial death from suspension of the body by a ligature around the neck using body weight as force.

Ligature Hanging

Hanging where a rope or similar object tightens around the neck; force is body weight.

Suicidal Hanging

Self-inflicted hanging; default assumption unless evidence indicates otherwise.

Homicidal Hanging

Hanging inflicted by another person, indicated by signs of struggle, injuries, or defensive wounds.

Strangulation

Asphyxia from external compression of the neck by ligature or hands, not reliant on body weight.

Manual Strangulation (Throttling)

Compression of the neck using hands or forearm; usually homicidal.

Garroting

Tightening a ligature around the neck, often with a stick or twisting device, to strangle.

Mugging (Strangle Hold)

Assailant compresses victim’s neck from behind with forearm or stick.

Smothering

Suffocation by blocking external air passages, such as mouth and nose.

Choking

Obstruction of internal airways by a foreign body, causing asphyxia.

Suicide

Intentional self-destruction, achieved by methods like hanging, firearms, poisoning, or drowning.

Accidental Death

Fatality occurring without intent and outside the victim’s control, e.g., lightning strike.

Contusion

Bruise; blood seepage under skin from blunt force causing discoloration.

Hematoma

Localized collection of blood in a newly formed cavity within tissues.

Abrasion

Removal of superficial skin layers through friction with a rough surface.

Incised Wound

Clean cut produced by a sharp-edged instrument; length exceeds depth.

Stab Wound

Penetrating injury where depth exceeds length, caused by pointed instrument.

Punctured Wound

Deep penetration by sharp, narrow object such as a nail or ice pick.

Lacerated Wound

Tear in skin and tissues from blunt trauma, producing irregular edges.

Defense Wound

Injury on victim’s hands or arms incurred while attempting to fend off an attack.

Linear Abrasion

Single scratch-like injury in a straight line.

Graze Abrasion

Broad superficial scrape from tangential contact with rough surface.

Imprint Abrasion

Patterned injury reflecting shape or texture of the object causing impact.

Coup Injury

Damage occurring directly beneath the site of blunt force impact.

Contra-coup Injury

Damage on the side opposite to where the force was applied.

Gunshot Wound

Open wound produced by a bullet entering (and possibly exiting) the body.

Abrasion Collar

Rim of rubbed skin around gunshot entrance due to bullet friction.

Powder Burns

Blackening, tattooing, or burning around entrance wound from close-range discharge.

Shotgun Wound

Injury from multiple pellets; pattern varies with distance from muzzle.

Rat Hole (Shotgun)

Serrated, scalloped shotgun entrance wound produced at 3–4 feet range.

Odd and Even Rule (Gunshot)

Even number of entrance and exit wounds suggests no bullet retained; odd number implies lodged projectile.

Virginity

State of a female who has not engaged in sexual intercourse; anatomically intact hymen may indicate but not prove it.

Defloration

Rupture or laceration of the hymen resulting from first sexual intercourse.

Hymen

Fold of mucous membrane partially covering vaginal opening; varies in shape and elasticity.

Satyriasis

Excessive, uncontrollable sexual desire in males.

Nymphomania

Excessive, uncontrollable sexual desire in females.

Pedophilia

Compulsive sexual attraction to pre-pubescent children.

Bestiality

Sexual activity between a person and an animal; also called zoophilia.

Necrophilia

Sexual attraction to or intercourse with a corpse.

Masochism

Deriving sexual gratification from receiving pain or humiliation.

Sadism

Deriving sexual gratification from inflicting pain or humiliation on others.

Fetishism

Sexual arousal requiring a specific object, body part, or scenario not typically considered erotic.

Voyeurism

Sexual gratification from secretly watching others undress or engage in intimate acts.

Exhibitionism

Obtaining sexual arousal by exposing one’s genitals to unsuspecting strangers.

Transvestism

Wearing clothing of the opposite sex for erotic or psychological gratification.

True Hermaphroditism

Rare condition where an individual possesses both ovarian and testicular tissue.