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Hottawa Stuff > Week 2 > Flashcards

Week 2 Flashcards

1
Q

Health and Safety

A

Employer must supply adequate training and protective equipment.

Employee must:
1) know the materials being used (read SDS)

2) Use protective equipment

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2
Q

Personal protectice equipment for fingerprint powders

A

1) Dust mask (half face with P100 dust cartridge

2) Protective clothing
- Lab coat
- Coveralls
- Appropriate clothing

3) Latex/Nitrile gloves
4) Eye protection when using UV or FL

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3
Q

Markings for developing impressions

A

1) Develop the latent impression
2) Make notations on scale (data tab)

3) Apply scale beside the fingerprint
- Beside/above/below at right angle

4) Apply:
- ‘R’ or ‘F’ number
- Date
- Initials
- File number

5) Circle the cluster, palmprint or footwear impression and markings
6) Powder over the markings

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4
Q

Three types of latent impressions

A

1) Latent
- Need to be enhanced

2) Visible
- in blood, dust, paint, etc

3) Molded
- in clay, grease, paint, etc

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5
Q

Factors to consider to determine whether and which powder to use

A

1) Presence of foreign material
2) Type of substrate

3) Probable age of print
- Cannot be determined by its appearance

4) Monetary or sentimental value
5) Portability

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6
Q

Purpose of powders

A

1) Make latent impressions visible
2) Enable contrast with background
3) Enable impressions to be photographed
4) Potentially enable the impressions to be lifted

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7
Q

Factors that affect the longevity of fingerprints

A

1) Atmospheric conditions
2) Substrate

3) Composition of Matrix
- Sweat, oil, blood…

4) Amount of matrix
5) Contamination

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8
Q

Types of development powders

A

1) Regular
2) Fluorescent
3) Magnetic (Regular and Fluorescent)

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9
Q

Bench notes begin at scene

A
  • Anatomical factor
  • Substrate
  • Matrix
  • Development medium
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10
Q

Black Powder

A

Best used on:

  • light coloured background items
  • porcelin, china, wood, painted wood, metal, gloss paper, cardboard
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11
Q

Silver/Lightning Grey

A

Use with caution!

Best used on:
- dark surfaces, clear glass, silverware, chrome / nikel / plated surfaces

DO NOT use on:

  • anything remotely porous
  • varnished/coated surfaces
  • oily finishes
  • floors
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12
Q

Chemist Grey

A

Easiest to use

Less effective on older prints

Can enhance or clean up latent prints developed with silver/lightning powder

BEST ON:

  • slightly oily, greasy or sticky surfaces
  • polished furniture
  • black hard plastic
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13
Q

Fluorescent powders

A

Used when desireable to eliminate background interference

MUST BE applied under UV light source

Applied with feather duster in vaccum cabinet

BEST ON:

  • multi-coloured surfaces
  • cut crystal
  • mirrors and highly reflective surfaces
  • glossy magazine covers
  • photographs
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14
Q

Magnetic Powders

A

Limited volatility

Can be applied to wood, paper, leather and other porous surfaces

  • may be used to enhance FP developled with other powders

DIFFICULTY:

  • verticial surfaces
  • porous surfaces
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15
Q

Friction Rodge Identification Process - Premises

Exam Question

A

1) Friction Ridges develop in the fetus in definitive form before birth
2) Friction Ridges are Persistent, except for permanent scarring
3) The specific Friction patterns and the details in small areas of Friction Ridges are unique and never repeat
4) Friction Ridges vary within patterns which allows them to be classified

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16
Q

Friction Rodge Identification Process - The Philosophy

Exam Question

A

Friction Ridge identification is established through the agreement of Friction Ridge formations in sequence

17
Q

Difference betwen:

Quantitative / Qualitative

Exam Question

A

Quantitative:
When the quality of detail is HIGH, the tolerance for dissimilarities is LOW and the requirement for quantity DECREASES

Qualitative:
When the quality of detail is LOW, the tolerance for dissimilarities is HIGH and the requirement for quantity INCREASES

18
Q

Dissimilarity

A

Difference in appearance between two Friction Ridge impressions

IE: Explainable difference

Pressure of deposition can cause Friction Ridges to look like a bifurcation

19
Q

Discrepancy

A

Presence of Friction Ridge detail in one impression that does not exist in the corresponding area of another impression

IE: Something you cannot explain

20
Q

Friction Ridge Identification process

A

ACE-V

Analysis
Comparison
Evaluation
- 
Verification
21
Q

ACE-V: Analysis

A

Gathering of objective information regarding the unknown impression to determine if the impression is suitable for comparison by assessing if there is sufficient quantity and quality of detail in the impression

22
Q

7 factors of the Analysis phase of ACE-V

A

1) Anatomicial factors
How object was handled
Digit determination

2) Substrate
Surface the impression was deposited
Any interference in shape of surface (curve)

3) Matrix (residue on finger)
Material that is deposited onto substrate
Most common is sweat/sebaceous glands

4) Development medium
Used to render impression or create contrast
Powders / chemicals

5) Deposition Pressure
Amount of pressure exerted on Friction Ridges when in contact with substrate
Can vary throughout impression

6) Lateral distortion
Movement of finger after contact with substrate
- initial contact
- maintained contact
- leaving the substrate

7) Clarity / Tolerance
2 functions:
- dictates level of detail (1,2,3) avail for comp
- dictates level of tolerance for dissimilarities

23
Q

Level 1 detail

A

Friction Ridges visible

Flow of Friction Ridges

Sometimes enough info for pattern type

Can be used to exclude
- Not used when heavy distortion

24
Q

Level 2 detail

A

Specific Friction Ridge paths

Major Ridge deviations
- endings, bifurcations, flexion creases

Can be used to exclude OR identify

25
Q

Level 3 detail

A

Consists of Intricate shapes that are present within the Friction Ridges
- relative pore locations, ridge unit shape, alignment or mis-alignment of ridge units

Can add weight to Identification

Cannot be used as basis for exclusion

Not as reliable as level 2 detail

26
Q

Tolerance

A

The tolerance for dissimilarities is dictated by the objective analysis of the questioned impression and by viewing all three levels of detail

Based on your OBJECTIVE analysis, you will give the Friction Ridge impression a subjective assessment for the tolerance towards discrepencies

27
Q

GYRO

A

System developed to provide a process of documentating the analysis and comparison phase of ACE-V

Uses system of: green, yellow, red, orange

In the unknown impression:

Green = highly confident will be in known

Yellow = moderate confidence in known

Red = great deal of uncertainty

Orange = used in comparison phase to indicate features not initially observed in analysis phase

28
Q

SWGFAST

A

High:
Level 1 distinct
Level 2 distinct
Abundant of Level 3

Medium-High:
Level 1 distinct
Most Level 2 distinct
Minimal Level 3

Medium-Low:
Level 1 distinct
Few Level 2 distinct
Minimial Level 3

Low:
Level 1 may not be distinct
Most Level 2 indistinct
No distinct Level 3

29
Q

ACE-V: Comparison

A

Side by side comparison

2 Stages:

1) Level 1; what class characteristics are present? (digit determination)
2) Can we reduce the donor source

Determine agreement based on:

  • Similiarity
  • Sequence
  • Spatial relationships

Comparitive measurements of all types of:

  • Details
  • Sequences
  • Configurations

Considers tolerance for variations in appearance

OBJECTIVE description of visual differences and agreeement

30
Q

ACE-V: Evaluation

A

Conclusion based on:

1) Analysis
2) Comparison

Provide explanation on differences when applicable

Clear statement of opinion

MUST be able to answer these 2 questions:
1) Is there AGREEMENT of FR detail between the unknown and known sample

2) Is there SUFFICIENT agreement in the FR detail to identify

31
Q

Pattern Force

A

The anticipated appearance of certain minutiae (ridge endings, bifurcations) in specific parts of a patterns ridge flow due to stresses placed on the developing friction skin in those locations

Loops:
Ridges flow in one side, recurve and flow out that same side. Tendency for ridge endings to develop in outflowing ridges

Whorls:
Not uncommon to find series of bifurcations below the core

Deltas:
Short ridges commonly found in/near a delta

32
Q

Objectivity

  • VS -

Subjectivity

A

Objectivity:
What you can see and explain as a result of your analysis

Subjectivity:
Personal decision based on your knowledge, training and experience

33
Q

3 Conclusions in ACE-V

A 
1) Identification:
Donors are the same: 
Sufficient features in agreement 
Originated from the same source
Likelyhood that impression is made by another source is so remote, considered practical impossibility

2) Exclusion:
Donors are not the same:
Sufficient features in disagreement
Originated not from same source

3) Inconclusive:
Cannot identity or exclude:
Must provide a reason:
1) Not enough information in agreement 
    - 5 Green, 2 Yellow and 2 Orange

2) Terrible quality known standard
- Cannot compare the ridges
- ie: tip of impression not recorded on C-216

34
Q

ACE-V: Verification

A

Should be a blind process!!

Verification is the independant examination by another qualified examiner

35
Q

Bias

A

Cognitive:
Effect of perpetual or mental processes on the reliability and validity of one’s observations

Contextual:
Effect of information or outside influences on the evaluation and interpretation of data

Confirmation:
Tendency to search for data or interpret information in a manner that supports one’s preconceptions

Hottawa Stuff (10 decks)

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