IAI CCSI flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Chain of custody

A chronological, documented record of every person who handled an item of evidence, with dates, times, and purposes of transfer, used to prove integrity from collection to courtroom presentation.

Grid search pattern

A search method that runs parallel lines in one direction, then repeats them perpendicular, giving double coverage of an area and reducing the chance of missed evidence.

Spiral search pattern

A search that moves in ever-widening circles from a central point outward, or inward toward a focal point, suited to confined or roughly circular scenes.

Zone search pattern

A method dividing the scene into labeled sectors searched individually, commonly used for large areas, buildings, and vehicles where one continuous pattern is impractical.

Triangulation measurement

Locating an item by measuring from two fixed reference points to the item, producing intersecting distances that fix its position in a horizontal plane.

Baseline coordinate method

A measurement technique establishing a straight reference line through the scene, then recording each item by perpendicular distance from that line and distance along it.

Rough sketch

An initial hand-drawn diagram made at the scene showing item locations, measurements, and reference points; it is later refined into a finished scale drawing.

Finished sketch

A precise, scaled drawing prepared from the rough sketch and field notes, typically including a legend, scale, orientation, and all measured evidence positions.

Photographic scale

A ruler or reference marker placed beside evidence in close-up photographs to allow accurate size determination; it must lie in the same plane as the item photographed.

Overall photograph

A wide view capturing the entire scene and its surroundings, establishing context and the relationship of the scene to adjacent areas before closer views are taken.

Mid-range photograph

A view showing a grouping of evidence or a specific area within the scene, bridging the overall context photo and the close-up detail photo.

Close-up photograph

A detailed image of a single item of evidence, taken both with and without a scale, filling the frame to record identifying features and condition.

Latent print powder

A fine powder applied with a brush to nonporous surfaces, adhering to oily residue left by friction ridge contact, then lifted with tape onto a contrasting backing card.

Cyanoacrylate fuming

A method where heated cyanoacrylate glue vaporizes and polymerizes on latent print residue, forming a white deposit on nonporous surfaces that can be enhanced with dye stains.

Ninhydrin development

A reagent sprayed or dipped onto porous surfaces such as paper that reacts with amino acids in print residue, producing a purple color after heat and humidity treatment.

Physical developer

A silver-based reagent used on porous surfaces, particularly items that were wet or previously processed, that deposits on print residue to reveal ridges.

Iodine fuming

A sublimation technique where iodine crystals vaporize and are absorbed by latent print residue, producing temporary brownish ridges that fade and must be photographed or fixed.

Angle of impact formula

For an elliptical bloodstain, the impact angle is the arcsine of the ratio of stain width to stain length; a circular stain indicates a perpendicular drop.

Area of convergence

The two-dimensional point found by drawing lines through the long axes of several related bloodstains; it indicates where the blood source was located in the horizontal plane.

Area of origin

The three-dimensional location of a blood source, calculated by combining impact angles with the area of convergence and back-projecting along the trajectories of the stains.

Directionality of bloodstain

The pointed or scalloped end of an elongated bloodstain indicates the direction of travel, with the tail pointing away from the source and toward the surface struck.

Transfer bloodstain pattern

A pattern created when a wet, bloody object contacts a surface, leaving a mirror-image impression such as a bloody shoe print, handprint, or fabric texture.

Cast-off pattern

Blood flung from a swinging weapon or limb, producing a linear series of stains whose direction and spacing help infer the number and direction of swings.

Void pattern

An absence of bloodstaining in an otherwise stained area, indicating that an object or person occupied that space during the bloodshed and was later moved.

Paper packaging for biology

Biological evidence is placed in breathable paper containers and air-dried; sealed plastic traps moisture and promotes bacterial growth and DNA degradation.

Reference sample

A known sample collected from a person, victim, or object for comparison with questioned evidence, packaged and labeled separately to prevent cross-contamination.

Substrate control

A sample of unstained material adjacent to a stain, collected to show what the surface alone contains and to support interpretation of test results on the stain.

Locard exchange principle

The principle that contact between two objects results in transfer of material between them, underpinning the search for trace evidence at scenes.

Scene security log

A written record of all persons entering and leaving the scene, with names, agencies, times, and reasons, supporting scene integrity and later testimony.

Alternate light source

A high-intensity or filtered light used to reveal evidence such as biological fluids, latent prints, hairs, and fibers that are not visible under ordinary lighting.

Questioned document packaging

Documents are handled by edges, placed between rigid supports or in paper folders, and kept away from moisture and folding to preserve indented writing and trace material.

Firearm evidence collection

Weapons are unloaded safely and secured with the muzzle pointed away; cartridges and casings are packaged separately and labeled by location to preserve pattern interpretation.