IAI SP5 key terms

The three-dimensional point in space from which blood drops traveled before striking a surface, estimated by projecting the long axes of stains backward along their angles of impact.

The acute angle between a blood drop's flight path and the target surface, calculated from the ratio of stain width to length; a circular stain indicates roughly 90 degrees.

The two-dimensional region on a surface where lines drawn through the long axes of several related stains intersect, indicating where the blood source was located relative to that surface.

Small droplets that separate from a larger parent drop and land around it, typically caused by surface tension breaking up as the parent drop spreads on impact.

A linear trail of bloodstains produced when blood flung from a moving object, such as a swinging weapon or limb, leaves the object along its arc of travel.

Blood droplets driven outward when a force strikes a blood source or a bloodied surface, with droplet size generally decreasing as the energy of the impact increases.

Blood droplets projected backward toward the source of a force, such as onto a shooter's hand or weapon when a close-range gunshot or blunt impact creates a wound.

An absence of bloodstains in an otherwise stained area, indicating that an object or person blocked the blood from reaching the surface and was later removed.

A stain created when a blood-bearing object or surface comes into direct contact with another surface, often preserving the shape or texture of the contacting item.

A bloodstain resulting from direct contact between a bloodied object and a surface, including swipe and wipe patterns that record motion or the outline of the object.

The documented, unbroken chronological record of who collected, handled, transferred, and stored each item of evidence, used to show it has not been altered or substituted.

The systematic recording of a crime scene through notes, sketches, photographs, and measurements, capturing conditions and item locations before anything is moved or collected.

A hand-drawn, not-to-scale diagram made at the scene showing the layout, fixed reference points, and approximate positions of evidence, later refined into a finished scale drawing.

A measurement technique that fixes evidence positions by recording perpendicular distances from a single straight reference line established between two known points at the scene.

A measurement approach that locates an item by recording distances from two fixed reference points, whose intersection places the item precisely on a scaled diagram.

The selection of appropriate containers, such as paper bags for biological items and sealed rigid containers for sharps, that preserve integrity and prevent loss, contamination, or degradation.

A sample of unstained material collected from near a questioned stain, used to show whether the surface itself, rather than the stain, produced a test result.

Features shared by a group of manufactured items, such as a shoe size or tread pattern, that can narrow a source to a category but cannot identify a single item.

Random, incidental features such as cuts, nicks, and wear marks acquired during use, which can support an association between a specific shoe or tool and an impression.

A known impression made from a suspected shoe or tool under controlled conditions, used for comparison with a questioned impression recovered from the scene.

The design and arrangement of raised and recessed elements on the outsole of a shoe, recorded in an impression and compared to determine make, model, and size.

A hard, fast-setting gypsum-based casting material used to capture three-dimensional impressions in soil, snow, or soft ground with minimal distortion of detail.

A sheet of gelatin-coated material pressed onto a surface to lift dust impressions or residue, then placed on a contrasting backing for preservation and examination.

A device that applies a static charge to a lifting film so dry dust impressions on hard surfaces transfer to the film without disturbing the underlying material.

A specialist who produces demonstrative exhibits, courtroom illustrations, reconstructions, and composite or postmortem images to communicate evidence clearly to investigators and jurors.

A facial image built from a witness's description, combining recalled features into a likeness used to generate investigative leads rather than to serve as identification.

The use of facial reconstruction, photographs, or sketches to identify deceased persons whose features are obscured, decomposed, or otherwise not visually recognizable.

The examination of photographs and digital images for authenticity, enhancement, measurement, and interpretation, often supporting comparisons of persons, objects, or scenes.

The technique of deriving accurate measurements and three-dimensional relationships from photographs, using known reference points or camera geometry to map a scene.

The apparent change in size, shape, and spacing of objects caused by camera angle, lens focal length, and distance, which must be controlled when comparing images.

The range of distance in front of and behind the focused subject that remains acceptably sharp, controlled by aperture, focal length, and camera-to-subject distance.

A ruler, label, or known-size object placed in a photograph so that dimensions of depicted items can be verified and measured later by a viewer or examiner.

A wide view showing the whole scene or a major area, establishing the relationship of evidence items to the surroundings before closer midrange and close-up images are made.

The process of establishing that a digital image is what it purports to be, examining metadata, file structure, and artifacts for signs of alteration or manipulation.

The number of images recorded per second in a video, which determines temporal resolution and must be known when timing events or comparing footage from different sources.

Aligning clocks or timestamps across video, audio, and other records so events captured by different systems can be placed in a single consistent timeline.

Processing such as stabilization, frame averaging, contrast adjustment, or demultiplexing applied to footage to improve visibility, with each step documented to preserve reproducibility.

The NTSC analog video standard whose visible picture area is commonly cited as 704 by 480 pixels, with 720-pixel frames including overscan and timing information.

The study of friction ridge skin that evaluates pores, edges, and ridge shapes to assess print clarity and support conclusions about whether two impressions share a common source.

Individual ridge features such as ridge endings, bifurcations, and dots, used at the second level of detail to compare the configuration of two friction ridge impressions.

The finest friction ridge features, including pore position, ridge width, incipient ridges, and edge shape, used when first- and second-level detail are insufficient for a conclusion.

A comparison method with four stages: Analysis of each impression, Comparison of their features, Evaluation of similarities and differences, and Verification by an independent examiner.

The application of reagents such as ninhydrin, DFO, or physical developer to porous or nonporous surfaces to make latent friction ridge residue visible for photography.

A latent print development method in which fine powder is applied with a brush or atomizer to adhere to oily residue on nonporous surfaces, then lifted with tape.

A standardized record containing rolled impressions of all ten fingers plus plain impressions, used for identification, enrollment, and comparison with latent prints.

A tenprint filing system that assigns values to pattern types on each finger to produce a numerical formula for manually locating records in a fingerprint file.

The overall configuration of friction ridges in a print, classified as arch, loop, or whorl, with subcategories used for filing and for exclusion during comparison.

An electronic tenprint capture system that scans fingers directly to produce digital records, replacing ink-and-paper cards and enabling rapid transmission to databases.

An Automated Fingerprint Identification System that encodes and searches friction ridge features against a database to return candidate records for human examiner review.