Fingerprints and ACE-V Methodology Quiz 4 Flashcards
Rideology
Study of friction ridge formation, in sequence, with sufficient detail to individualize.
Skin
Classified as an organ. Largest organ in the body. Two main layers: Epidermis (outer layer). Dermis (inner layer).
Epidermis
Made up of several smaller layers.
Innermost layer most important because it is “genereting layer”.
Dermis
Layer of skin in animals that leather comes from.
Contains blood vessels, glands, and nerves.
Provides generating layer with nutrients.
Creating Scars
Cuts through epidermis that reach dermal papillae will leave scar as healthy skin cells cannot be regenerated due to damage to generating cell layer.
Papillae
Double rows of peg-like areas in dermis that provides nutrients to “generating” layer.
Fetal Fingerprint Development
12 weeks friction ridges start to form.
Tension and pressure created by volar pads shape and alter patterns.
Volar Pad Development
At 6 weeks some pad start to appear.
At 10 weeks pads are prominent and thumb is rotated.
Volar Pad Patterns
Arches usually have low pads.
Whorls believed to form from high-centered pads.
Loops form from intermediate pads.
Secondary or Incipient Ridges
Contain no sweat pores.
Look like misprints or smaller, underdeveloped ridges.
Can use for identification.
Pattern Percentages
Loops 65%.
Whorls 30%.
Arches 5%.
Loops
ANY recurve at all is a loop.
1 core, 1 delta.
Arches
Run one side to the other, with no backward turn.
2 types: Plain and Tented.
0 cores, 0 deltas.
Plain Arch
Even ridge flow from side to side.
No significant “up thrust”.
Tented Arch
Have significant up-thrust and don’t have same “easy” flow pattern as plain arches.
Whorls
Some ridges make a turn through at least one circuit.
Any pattern with 2 or more deltas.
Types of Whorls
Plain Whorl.
Central Pocket Loop Whorl.
Double Loop Whorl.
Accidental Whorl.
Plain Whorl
One or more ridges which make or tend to make a complete circuit.
1 core, 2 deltas.
Central Pocket Loop Whorl
At least one recurving ridge or obstruction at right angles to line of flow.
Ridges make one complete circuit which may be spiral, oval, circular, or any related variant.
1 core, 2 deltas.
Double Loop Whorl
2 separate and distinct loop formations with 2 separate and distinct shoulders for each.
One or more ridges make complete circuit.
2 cores, 2 deltas.
Accidental Whorl
Consists of two types of patterns with the exception of the plain arch.
1+ cores, 2+ deltas.
Print Value
Sufficient unique details present that when compared a conclusion can be reached.
Determining Print Value
Substrate. Matrix. Development medium. Deposition pressure. Anatomical orientation.
No Value Prints
Analysis for no value conducted prior to and regardless of whether comparisons will be conducted.
Can still be used for exclusions.
Level 1 Detail
Ridge Flow.
Cores, Deltas, Scars, Pattern Classification, and Orientation.
Individualization CANNOT occur at this level, but exclusions can.
Level 2 Detail
Ridge Path.
Characteristics (ending ridge, bifurcation, dot).
Location, type, direction, and relationship.
Individualization CAN occur at this level, as well as exclusions.
Galton Details
Ridge Ending. Bifuracation. Dot. Island. Enclosure.
Level 3 Detail
Ridge Attributes.
Edge/end shapes, width, angles pores.
Friction ridge morphology (secondary creases, ridge breaks, etc.)
Individualization CAN occur at this level.
Target Group
Area within print that appeals or stands out to you.
Never choose delta or core.
Determine unique characteristics.
All levels of detail.
ACE-V Methodology
Provides structure and guides examiner through analysis.
Based on sound scientific principles.
Conclusions are objective.
Assure validity and reliability of conclusions.
Include both qualitative and quantitative methods.
ACE-V Methodology: Application
Applied regardless of the combination of impressions types (ie unknown vs. known, known vs. known, unknown vs. unknown).
Analysis
Assessment of friction ridge impression to determine “value” by using levels of detail.’
First latent prints, then known exemplar(s).
Quality-Influencing Factors
Residue/Matrix. Deposition (pressure). Surface/Substrate. Environment. Development medium. Preservation method. Condition of friction ridge skin.
Comparison
Direct or side-by-side observation of detail to determine whether details match based on similarity, sequence, and spatial relationship.
Evaluation
Forming a conclusion based on analysis and comparison of friction ridge impressions.
Evaluation Conclusions
All conclusions are reproducible.
Can declare individualization, exclusion, or inconclusive.
Individualization
Identification.
Comparisons of sufficient quality (clarity) and quantity of friction ridge detail in agreement.
Two impressions orginated from the same source, to the exclusion of all others.
Exclusion
Comparisons of sufficient quality (clarity) and quantity of friction ridge detail NOT in agreement.
Determined to have originated from different sources.
Inconclusive
Examiner unable to individualize or exclude source of impression due to lack of sufficient details.
This conclusion must NOT be construed as statement of probability.
Conclusions of Probability
Probable, possible, or likely identification conclusions are outside the acceptable limits of this science.
Verification
Independent examination by another qualified examiner.
ALL individualizations (identifications) must be verified.
Exclusion or inconclusive results may also be verified.
Verification Steps
Supervisor selects verifying examiner. Provides all info from first examiner. Verifier reviews info. If conflicting opinions arise, conflict resolution. Info returned to orginal examiner.
Verifying Examiner
Also uses ACE-V method.
Documents their process.
Returns all info to Supervisor.
Blind Verification
Independent examination of impression by another qualified examiner who does NOT know conclusion of first examiner.
Can be conducted on individualizations, exclusions, and inconclusives.
Anatomical Origin
Palm, finger, toe, etc.
Substrate
Surface type (glass, tape, paper, etc.)
Matrix
Material covering friction ridge skin that is left behind when object is touched (oil, sweat, paint, etc.)
Development Medium
What was used to visualize latent print (forensic light source, chemicals, powders, etc.)
Pressures
Deposition pressure (downward). Lateral pressure (slippage).
