29 Questions
Which of the following is a type of physical pattern evidence?
Fingerprints
What is the main focus of physical pattern examination?
Reconstruction
Which approach is the most widely used for individualization using physical patterns?
Physical matching
What is the term used for identification based on structural features in physical pattern recognition?
$Morphological$ identification
What affects the size of a bloodstain pattern and its edge configuration?
Original droplet size, surface texture, surface resilience, surface porosity/absorbency, speed at moment of impact
What produces more ragged edges in a bloodstain pattern?
Higher velocities and rougher surfaces
What is the formula for the angle of incidence in terms of the minor and major diameter?
$\theta = \arccos\left(\frac{d}{D}\right)$
What kind of bloodstain pattern emanates in a radial pattern from repeated blows?
Patterns from blows
What is the average volume of droplets formed slowly?
~0.05 mL
"Patterns from artery spurts" result from what type of blood activity?
"Spurting blood in rhythm with pulsating contractions of the heart"
"Contact patterns and transfers" are useful for revealing what kind of characteristics?
"Class or individual characteristics (fingerprints, footprints, fabric imprints)"
"Blood patterns from shooting" result in what kind of droplet travel pattern?
"Conical pattern in general direction of bullet"
'Preserving and interpreting bloodstain patterns' requires careful documentation to reconstruct what kind of relationships?
'Geometric and spatial relationships between people and objects'
What are acceptable techniques for capturing footwear impressions in snow?
Highlighting with colored aerosol sprays, using a combination of snowprint wax with dental stone, and sulfur casting
What information is included in footwear outsole databases?
Manufacturer, model, size, and production dates
What are considered individualizing characteristics for both footwear and tire track impressions?
Wear patterns, irregularities, damage, cuts, and accidental or intentional marks
What does laboratory examination of physical pattern evidence require consideration of?
Class and individualizing characteristics, cast shrinkage, movement when the pattern was left
Where can physical pattern evidence also be found?
Blood spatter
What can bloodstain patterns be valuable in reconstructing?
A crime scene
What does interpretation of blood droplet dynamics include understanding?
Terminal velocity
What do tire track imprints/impressions have as class characteristics?
Zigzag pattern
What is involved in exemplar preparation for footwear impression evidence?
Imprint methods such as inked prints and oil/black powder prints
What information do tire track imprints/impressions provide?
Zigzag pattern characteristics
Which method is used for documenting footwear patterns from outsoles?
Photography
What is the recommended method for collecting dry dust shoeprints?
Lifting with adhesive tape
Which type of pattern evidence can be classified based on wheelbase and track widths?
Tire tracks
What is used for recording the general location and orientation of pattern evidence?
Long and medium-range photographs
What is the purpose of casting materials in pattern evidence collection?
Creating 3-D reproductions
What is involved in indirect physical matches of pattern evidence?
Impressions and striations examination
Study Notes
Pattern Evidence Collection and Analysis
- Pattern evidence includes direct physical matches, indirect physical matches, and general form comparisons.
- Direct physical matches involve physical fits and definitive individualizations, and should not be attempted in the field to prevent damage to the evidence.
- Indirect physical matches include imprints, indentations, and striations, which are examined in the lab for continuity of patterns and surface markings.
- Documentation, collection, and preservation of pattern evidence involve thorough documentation through photographs, notes, and sketches prior to any collection or preservation.
- Collection and preservation methods for physical pattern evidence include lifting of imprint patterns, casting materials, and 3-D pattern reproductions.
- Tire tracks can be classified based on wheelbase, front, and rear track widths, and careful measurement can identify the manufacturer of the vehicle involved.
- Footwear patterns from outsoles are documented with photography, and electrostatic lifting is used for shoeprints in dry dust.
- Documented examples of pattern evidence include fingerprints, blood spatter analysis, firearms and toolmarks evidence, glass reconstruction, and footwear imprints and impressions.
- Long and medium-range photographs are used to record general location and orientation of pattern evidence, while close-up photos record detail and irregularities.
- Pattern evidence individuations are subjective in nature and include hair comparisons, facial recognition, handwriting, dental x-rays, and voiceprint comparisons.
- The degree of individualization in pattern evidence depends on the number and type of features present in the mark and the relationship of the mark to the case.
- Pattern evidence collection and analysis methods are outlined in the book "Crime Investigation" by P.L. Kirk.
Test your knowledge about footwear impression evidence including detection, recovery, and examination techniques. Learn about electrostatic lifting and casting of shoeprints.
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