Forensic Science Review Flashcards

Vocabulary flashcards covering core concepts, key figures, processes, and databases across Death Investigation, Bloodstain Pattern Analysis, Fingerprints, and Physical Evidence.

Forensic Pathologist

Medical doctor who determines the cause of an undetermined or unexpected death, estimates postmortem interval, and conducts autopsies.

Postmortem Interval (PMI)

The time that has elapsed since death.

Autopsy

Examination of a body after death.

Forensic/Medicolegal Autopsy

An autopsy performed to determine the cause of death and confirm the manner of death.

External Examination (Autopsy)

The phase of an autopsy involving collection of physical evidence, measuring/weighing the body, checking rigor and lividity, inspecting clothing, sampling under fingernails, and extracting vitreous fluid.

Internal Examination (Autopsy)

The phase of an autopsy involving the dissection of the human body, incising, inspecting, weighing, and measuring organs, checking for pathology, and suturing the body.

Cause of Death

The physical action or injury that initiates the series of events ending in death, such as blunt force trauma, sharp-force injuries, asphyxia, gunshot wounds, or substance abuse.

Manner of Death

The determination made after cause of death that results from the entire investigation; categories include Homicide, Suicide, Accidental, Natural Causes, and Undetermined.

Asphyxia

Interference with the intake of oxygen.

Algor Mortis

The postmortem process resulting in the loss of heat and fall in body temperature until reaching ambient temperature, typically cooling at 1 to 1-1/2 degrees Fahrenheit per hour starting an hour after death.

Rigor Mortis

Latin meaning 'stiffness of death'; results in shortening of muscle tissue and stiffening of body parts, starting within 4 to 6 hours and lasting up to 24 to 48 hours.

Livor Mortis

Also known as hypostasis; the pooling of blood and discoloration in areas of the body closest to the ground due to gravity.

Lividity

Bluish-purple discoloration of the skin resulting from postmortem blood pooling.

Blanching

Whitish discoloration of skin in areas of livor mortis caused by applied pressure.

Putrefaction

Decomposition of organic matter after death, visible within 3 to 4 days, characterized by skin sloughing/blistering, marbling, and gas accumulation.

Forensic Entomology

The study of insects and their relation to a criminal investigation, used to estimate PMI based on the most developed stage of flies present on a body.

Forensic Anthropology

Identification and examination of human skeletal remains to determine age, sex, ancestry, stature, and trauma.

Antemortem Trauma

Skeletal trauma or injury occurring before death, characterized by signs of active healing.

Perimortem Trauma

Skeletal trauma or injuries occurring near or around the time of death.

Postmortem Trauma

Damage or trauma occurring to the body or skeleton after death.

Crime Scene Reconstruction

The process of seeking to establish all actions associated with a crime or incident and, when possible, ordering those actions chronologically.

Bloodstain Pattern Analysis (BPA)

The examination of the physical characteristics of bloodstains (dispersion, shape, volume, pattern, number, and size) to define what caused them in a scene.

Alexandre Lacassagne

French military surgeon who studied gunshot wounds and founded the Lacassagne School of Criminology at the University of Lyons.

Surface Tension (Blood)

The force that pulls surface molecules of liquid blood together, decreasing surface area to form a spherical drop held by cohesive forces.

Contact and Collapse Phase

The first phase of blood drop impact where the droplet hits the target surface and collapses from the bottom upward.

Displacement Phase

The second phase of blood drop impact where the sphere collapses against the target surface and the majority of blood volume is displaced outward into the boundary.

Dispersion Phase

The third phase of blood drop impact where blood is forced into the boundary rim and dimples that rise upward and opposite to the direction of original momentum.

Retraction Phase

The fourth phase of blood drop impact where surface tension attempts to pull the fluid of the stain back into a single form.

Impact Phases

The four distinct sequential events occurring when a blood droplet impacts a surface: Contact/Collapse, Displacement, Dispersion, and Retraction.

Angle of Impact

The acute angle formed by the direction of a blood drop and the plane of the surface it strikes, calculated using $\sin(\theta) = \frac{\text{Width}}{\text{Length}}$.

Low Velocity Spatter

Bloodstain pattern produced by low velocity force (~5 feet/second or less), resulting in large drops with diameters of 4 millimeters or more.

Medium Velocity Spatter

Bloodstain pattern produced by medium velocity force (~5-25 feet/second), resulting in small drops with diameters of 1 to 4 millimeters (e.g., blunt-force trauma).

High Velocity Spatter

Bloodstain pattern produced by high velocity force (~100 feet/second), resulting in fine drops with diameters less than 1 millimeter (e.g., gunshot exit wounds or explosions).

Cast-Off Spatter

Bloodstain pattern created when a blood-covered object flings blood in an arc onto a nearby surface, with stain tails pointing in the direction of object movement.

Arterial Spray Spatter

Bloodstain pattern resulting from blood exiting the body under pressure from a breached artery or the heart.

Expiratory Blood Pattern

Blood expelled under pressure from the mouth, nose, or respiratory system, which may contain air bubbles or appear diluted with saliva or mucous.

Void Pattern

An area devoid of blood spatter created when an intermediate object or person blocks the deposition of blood onto a surface.

Transfer Pattern

A bloodstain pattern created when an object bearing wet blood comes into direct contact with another object.

Swipe Pattern

The transfer of blood onto a surface not already contaminated with blood, typically featuring a feathered edge indicating direction of motion.

Wipe Pattern

A bloodstain pattern created when an object moves through an existing bloodstain, removing blood and altering its appearance.

Skeletonization

The phenomenon where the outer edges of a bloodstain dry to the surface first, remaining intact even if the central blood is later disturbed.

Fly Spots

Small pattern-like bloodstains resulting from fly activity, tracking, and regurgitation around a bloodied object.

Alphonse Bertillon

French police expert who introduced the first systematic identification system in 1883 using portrait parlé and anthropometry.

Portrait Parlé

A verbal description of a perpetrator's physical characteristics combined with full-length and profile photography, developed by Bertillon.

Anthropometry

A system of personal identification based on 11 precise body measurements, developed by Alphonse Bertillon.

Sir Francis Galton

English scientist who published Finger Prints in 1892, establishing the uniqueness, permanence, and three main pattern types of fingerprints.

Sir Edward Henry

Developer of the fingerprint classification system based on ridge patterns in 1897, which remains in wide use across English-speaking countries.

Minutiae

Specific, detailed ridge characteristics on friction skin that determine fingerprint uniqueness.

Ridge Ending

A minutiae point where a friction ridge terminates or stops abruptly.

Bifurcation

A minutiae structure where a single friction ridge splits or forks into two separate ridges.

Enclosure (Lake)

A minutiae structure where a single friction ridge splits into two ridges and quickly re-joins to form a single ridge.

Ridge Dot (Island)

A small, isolated fragment of a friction ridge that matches the approximate size of a single ridge unit or pore.

Spur

A fingerprint minutiae feature characterized by a short ridge branching off a longer friction ridge.

Crossover (Bridge)

A short friction ridge that connects two parallel ridges.

Dermal Papillae

The boundary layer between the epidermis and dermis that determines the form and pattern of friction ridges on skin.

Latent Fingerprint

An invisible impression left on a surface by sweat, perspiration, and body oils transferred from friction ridges.

Loop Pattern

A fingerprint pattern class where ridge lines enter from one side, curve around, and exit on the same side; must contain exactly one delta.

Whorl Pattern

A fingerprint pattern class that is generally rounded or circular in shape and contains two or more deltas.

Arch Pattern

A fingerprint pattern class where ridge lines enter from one side of the pattern and flow out the opposite side.

Fingerprint Patterns

The three primary visual classification groups of friction ridge arrangements: Loop, Whorl, and Arch.

Delta (Fingerprint)

The ridge point nearest the divergence of type lines where three ridge lines meet to form a triangular shape.

AFIS

Automated Fingerprint Identification System; computer database software that scans, digitizes, and matches fingerprint minutiae.

Livescan

An inkless digital capture device that records finger and palm print impressions pressed against a glass platen.

Visible Print

A fingerprint impression made when friction ridges contact a colored material such as blood, paint, grease, or ink.

Plastic Print

A three-dimensional fingerprint impression left on a soft material such as putty, wax, soap, or dust.

RUVIS

Reflected Ultraviolet Imaging System; a device that uses invisible UV light to locate latent fingerprints on nonabsorbent surfaces without chemicals.

Iodine Fuming

The oldest latent print fuming method in which solid iodine crystals sublimate into gas to reveal temporary prints on porous/nonporous items.

Ninhydrin

A chemical reagent that reacts with amino acids in sweat to visualize latent fingerprints as a purple-blue color on porous materials like paper.

Superglue Fuming

A latent print technique that uses cyanoacrylate ester vapors in an enclosed chamber to produce a white print on nonporous items.

Physical Evidence

Any object that can establish that a crime has or has not been committed or can link a crime and its victim or its perpetrator.

Identification (Evidence)

The process of determining a substance's physical or chemical identity with near absolute certainty permitted by analytical techniques.

Comparison Analysis

An examination subjecting a suspect specimen and a standard/reference specimen to identical tests to determine if they share a common origin.

Individual Characteristics

Properties of evidence that can be attributed to a single common source with an extremely high degree of probability (e.g., DNA, fingerprints, bullet striations).

Class Characteristics

Properties of evidence that can only be associated with a group or category rather than a single source (e.g., ABO blood type, paint chips).

CODIS

Combined DNA Index System; the national database that enables crime laboratories to exchange and compare digital DNA profiles.

NIBIN

National Integrated Ballistics Information Network; a forensic database used to acquire, digitize, and match markings made by firearms on bullets and cartridge casings.

PDQ

International Forensic Automotive Paint Data Query; an international database containing chemical and color information on original factory automotive paints.

SICAR

Shoeprint Image Capture and Retrieval; a computer database system used for storing and matching footwear impression patterns.

NamUs

National Missing and Unidentified Persons System; a national resource providing free forensic services (odontology, fingerprints, anthropology, DNA) for missing and unidentified person cases.