IAI CBPA key terms

The forensic discipline of examining the size, shape, distribution, and orientation of bloodstains to reconstruct events that produced them, such as the type of force, direction, and number of impacts.

A trained examiner who documents stains, classifies patterns, and offers opinions about the physical events that created the deposition, often distinguishing between possible and probable mechanisms.

The standardized vocabulary and definitions adopted by the scientific working group for bloodstain pattern analysis, used so that reports and testimony carry consistent meaning across examiners and jurisdictions.

A stain created when a wet, blood-bearing object contacts a surface and leaves a recognizable image or smear, such as a bloody handprint, footwear impression, or fabric texture.

A transfer stain produced by direct contact between a blood-covered object and a receiving surface, often preserving the shape of the object or a portion of it.

A transfer pattern made when a blood-bearing surface moves across a non-bloody surface, producing a smeared streak whose direction can sometimes be inferred from feathering or edge detail.

A pattern created when an object moves through a wet bloodstain already present on a surface, altering or removing it and often leaving streaks that indicate the direction of movement.

A radiating group of small stains produced when a force strikes a blood mass, sending droplets outward from the point of impact; the pattern helps estimate the area of origin.

The three-dimensional region in space from which blood droplets in an impact pattern are calculated to have traveled, estimated by projecting droplet trajectories backward along their angles of impact.

The two-dimensional region on a target surface, found by extending the long axes of individual stains backward, where the lines intersect and indicate the horizontal location of the blood source.

The acute angle between a droplet's flight path and the target surface, calculated from the ratio of stain width to stain length and used to reconstruct trajectory in three dimensions.

A bloodstain whose length exceeds its width because the droplet struck the surface at an oblique angle, with the narrow end generally pointing in the direction of travel.

The feature of a bloodstain or pattern that indicates the direction blood was moving when it was deposited, often shown by a tapering tail, scalloped edge, or spine pointing along the flight path.

A narrow ridge or line of blood extending from the edge of a stain, typically on the side opposite the direction of travel, formed as the droplet spreads and rebounds on impact.

Small droplets that separate from a parent stain and land nearby when a droplet strikes a surface, often appearing ahead of the parent in the direction of travel.

A line or arc of droplets thrown from a blood-bearing object such as a weapon when it is swung, with each swing producing a separate linear pattern whose number can suggest swing count.

A pattern of droplets ejected under pressure from a breached artery, often appearing as a repeating arc or spray whose size and spacing reflect the victim's pulse and movement.

Blood forced from the mouth or nose by exhaled air, producing fine droplets often mixed with saliva or mucus and frequently showing bubble rings or a lighter appearance.

A stain formed when blood falls under gravity and strikes a surface, typically circular when the surface is horizontal and elongated when the surface is inclined.

A group of stains produced by blood dripping from a source such as a wound, weapon, or clothing, often arranged in a line or cluster reflecting movement of that source.

A bloodstain created by blood falling under gravity alone, without added force, resulting in a relatively circular stain on a horizontal surface with little spatter.

An accumulation of liquid blood on a surface, which may spread and later dry with a characteristic edge; its location and shape help infer body position and movement.

An area free of bloodstains surrounded by staining, indicating that an object or person occupied that space when blood was deposited and was later moved.

Any change to a bloodstain or pattern after deposition, such as wiping, dilution, saturation, or decomposition, that can obscure the original pattern and must be documented.

A dried bloodstain whose center flakes away or is removed, leaving a ring-like outline; this indicates the stain was dry when disturbed and helps sequence events.

The interval needed for a bloodstain to dry, influenced by volume, surface porosity, temperature, and humidity; it is used cautiously to estimate how much time has passed.

The airborne travel of a blood droplet, governed by gravity, air resistance, and initial velocity, which determines its size, shape, and the pattern it produces on impact.

The technique of stretching string or cord through the long axes of selected stains to visualize convergence and to estimate the area of origin in three dimensions.

The receiving surface on which blood is deposited; its texture, porosity, and angle strongly affect stain size, shape, and the interpretation of the resulting pattern.

The location where a blood droplet or blood-bearing object first contacts a surface, distinct from the area of origin, which lies back along the droplet's flight path.

The primary stain formed by a droplet striking a surface, from which smaller satellite droplets may separate and land nearby during the same impact event.

The examiner's process of grouping stains by shared physical characteristics such as size, shape, distribution, and orientation, then assigning them to a recognized category.

The systematic recording of bloodstain evidence through notes, photography with scale, sketches, and measurements, forming the basis for later analysis and courtroom presentation.

The documented, unbroken record of who collected, handled, and stored bloodstain evidence, used to show that items were not altered or contaminated before analysis.

A screening test, such as luminol or a chemical color change, that indicates blood may be present but is not confirmatory and must be followed by specific laboratory testing.

A reagent that emits light when it reacts with the iron in hemoglobin, used to locate latent or cleaned bloodstains; its glow is presumptive and can be affected by other substances.

The path a droplet or blood-bearing object followed before deposition, inferred from stain shape, tails, spines, and the arrangement of satellite droplets around a parent stain.