FKA 2

Question 1

Describe Dr. William Babler’s research regarding prenatal development of friction skin:

Answer 1

Focus was on how the hand becomes evident in the human fetus at 5-6 weeks old. At 6 weeks the distinct fingers elongate. At 7 weeks the the hand plate differentiates into cartlidge and the tissue between finger begins to disappear. During this time the volar pads (mesenchmal tissue transiet swellings) begin to appear. Week 8 - The phalanges ossify (turn into bone) and the joints begin to form. 8.5 weeks - metacarpals ossify and a hand similar in proportion to the infant has developed.
Volar Pads - First begin to appear at 6.5 weeks on the palm and 7.5 weeks on the fingers. There are both primary and secondary volar pads that form. 6.5 weeks to 10.5 weeks - the apical pads that are evenly rounded begin to demonstrate individual variation. The primary pads regress after 10.5 weeks. As Volar Pads regress around 10-11 weeks it is the initiation of the epidermal ridge differentiation.
Flexion creases develop concurrently with volar pads.
Epidermal Ridges - critical period of primary ridge differentiation is between 11 and 17 weeks. Ridges develop in the basal layer and proliferate rapidly during the growth of the hand filling in any voids. This development happens at the epidermal and dermal interface not yet visible on the surface of the skin. 15- 17 weeks secondary ridges form and the stratum corneum develops. At 24 weeks the fetus has an epidermal ridge system the same as adult morphology. 24 weeks the dermal papillae form.
Ridges don’t form at the same time - they start typically on fingers first and begin in separate fields which then meet together.
Overall although there is a genetic component to dermatoglyphic traits - the pad topography, growth rates, and stress on the epidermis influence the ridge alignment.
At the time of ridge formation the pattern is influenced by the volar pad. High round volar pad would result in a whorl. Low pad an arch. Intermediate pad a loop.
Thickness of the skin during ridge formation may affect pattern.
Bone ossification may affect pattern type.
Chromosomal abnormalities may affect pattern type - delayed development of ridges = higher number of arches.
Deep ridge depth during development is more closely linked to whorl patterns. Shallower depth is associated to arches.

Question 2

What is the difference in structure between the basal cells in the primary and secondary ridges?

Answer 2

• Primary Ridges contain less keratin than Secondary Ridges.
• Primary ridges with the basement membrane are slightly undulated (morphology similar to stem cells and can multiply by tissue demand or injury), while the secondary ridges contain long projections that extend deep into the dermis anchoring them.
• Secondary ridges go through mitosis in the basal layer. Primary ridges go through mitosis in the superbasal layer before pushing into the Stratum Spinosum due to transient amplifying cells - more cells are needed on surface ridges due to greater abrasion.
• Keratinocytes express keratins not expressed elsewhere on the body - K9 is only found in keratinocytes in basal cells above primary ridges and K6 is only found along the vertical segments of the primary ridgess; K16 is only found in keratinocytes of the secondary ridges and dermal papillae

Question 3

Meissner Corpuscles:

Answer 3

They are found in about every 4th dermal papillae and are nerve endings that function as touch receptors as well as transmission of pressure

Question 4

What is the primary cell of the epidermis?

Answer 4

Keratinocytes

Question 5

What prevents the migration of cells of the basal layer of the epidermis?

Answer 5

Hemidesmosomes of the basal keritinocytes and the interlocking fibers throughout the basement membrane prevent basal cells from migrating.

Question 6

What phenomenon ensures that basal cell proliferation is stimulated and inhibited in a coordinated manner?

Answer 6

Cell Communication

Question 7

According to Dr. Okajima, what are two subtle changes to the surface of friction skin as a person ages?

Answer 7

Surface ridges flatten making appearance less sharp and loss of elasticity causes skin to wrinkle.

Question 8

What are the three healing phases of a wound to skin?

Answer 8

1. Inflammation: disruption of blood vessels in the dermis causes blood to spill into surrounding tissues, which directs clotting and recruits cells from the immune system, which kills bacteria. The dermal cells begin repairing the dermis and the endothelial cells begin repairing blood vessels.
2. Proliferation and Tissue Formation: Basal Keratinocytes at the edge of the wound are exposed to the dermis which dissolves the desmosomes and hemidesmosomes, so the basal keratinocytes begin branching out laterally as actin filaments form inside the Basal cell. The cells esssentially crawl across the wound dividing and healing the skin.
3. Tissue Remodeling: Once the epidermis has resurfaced the dermis continues to remodel and reinforce the scar tissue weeks to months afterwards. Resulting in a new template within the stratum basal and the effects of the surounding epiderms (pinching).

Question 9

What causes puckering of ridges during the formation of a scar at an injury site?

Answer 9

The Dermis contracts to shorten the distance that the epidermis kerotinocytes have to travel to repair the skin.
Developmental Noise – cells rapidly proliferate and reconstruct, but no longer have the blueprints for primary and secondary ridges, which results in puckering of the ridges at these injuries.

Question 10

Why is it important for a fingerprint expert to understand the physical limitations of friction skin?

Answer 10

This offers improtant value in analyzing friction ridge impressions as if the variation in appearance between two impressions goes beyond the physical limitations of the skin the impressions cannot be from the same source.

Question 11

Dr Kimura’s research identify when prominent flexion creases develop:

Answer 11

Week 8 - Thenar crease develop
Week 9 - Finger creases develop
Week 10 - Toe creases develop
Week 11 - Distal Transverse Crease develops
Week 13 - Proximal Transverse Crease develops

Question 12

What is meant by volar pad regression?

Answer 12

The volar pad remains rounded during rapid growth (9-10 weeks) after which they begin to demonstrate individual variation in shape and position - volar pad isn’t shrinking but are overtaken by faster growth of the larger surrounding surfaces

Question 13

According to Dr. Okajima, Chacko, and Vaidya’s research – when do dermal papillae begin to form and when do they stop?

Answer 13

They begin to form at approxiamately 23 weeks and continue to become more complex throughout fetal formation and into adulthood.

Question 14

The onset of cellular proliferation – which begins primary ridge formation – occurs in what three distinct areas?

Answer 14

1. The apex of the volar pads corresponding to core fingerprint pattern
2. The distal periphery or near the tip of the finger
3. The distal interphlalangeal flexion crease (below the delta)

Question 15

Name the three main areas of the palm:

Answer 15

Interdigital
Thenar
Hypothenar

Question 16

Name the three groups of flexion creases found in the palm:

Answer 16

Major Flexion Creases
Minor Flexion Creases
Secondary Creases

Question 17

Name the major palmar flexion creases:

Answer 17

Thenar Crease
Proximal Transverse Crease
Distal Transverse Crease

Question 18

Can palmar flexion creases be used for personal identification?

Answer 18

The palmar flexion creases when applied to the identification process are suitable for personal identification - they are persistent and variable enough to individualize. Are suitable alone or when used in conjunction with friction ridges.

Question 19

What are the basic premises upon which fingerprint identification is based?

Answer 19

1. Friction ridges develop on the fetus in their definitive form before birth
2. Friction ridges are persistent throughout life except for permanent scarring
3. Friction ridge patterns and the details in small areas of friction ridges are unique and never repeated
4. Overall friction ridge patterns vary within limits which allow for classification

Question 20

What is the philosophy of fingerprint identification as stated in the IFIM?

Answer 20

Friction ridge identification is established through the agreement of friction ridge formations, in sequence, having sufficient uniqueness to identify.

Question 21

What is referred to as the holistic assessment approach to fingerprint identification?

Answer 21

Assessing if there is sufficient quantity and quality of detail (clarity) in the impression, and if the same quality and quantity of detail was found in the known impression.

Question 22

Name and summarize the methodology you use to identify a fingerprint?

Answer 22

ACE-V Method

Analysis - assessment of an impression to decide on suitability for comparison.

Comparison - thorough side-by-side (ridge-to-ridge) comparison of all levels of details to determine whether two impressions are in agreement or disagreement, based on features, sequences, and spatial relationships within the tolerances established by the analysis of clarity and distortion.

Evaluation - examiner’s assessment of the value of details observed during the analysis and comparison which forms the basis for a conclusion. (Identification, Inconclusive, Exclusion)

Verification - a requirement for an independent analysis, comparison, and evaluation by a subsequent certified examiner

Question 23

What is the purpose of the analysis stage of ACE-V?

Answer 23

Assess the suitability of an unknown impression based on the quantitative-qualitative Friction Ridge Analysis

Question 24

There are three levels of detail which can be observed in a fingerprint impression. Describe each level and explain its significance to the identification process

Answer 24

Level 1 - Overall flow of friction ridges - may or may not include a pattern - cannot be used independently for identification, but can narrow down a prospective group to compare. Can be used to exclude.
Level 2 - Observation of the specific path of friction ridges and associated events in and of themselves as well as in relation to the other ridges next to a single ridge. Includes ridge endings, bifurcations, scars, etc… Can be used to identify or exclude.
Level 3 - Intrinsic ridge shapes, widths, and relative pore locations. May not always be visible in an impression, but have the most discriminating power.

Question 25

In the context of friction ridge analysis – what does “vestige” refer to?

Answer 25

References a sharp angular formation which do not flow in concert with other ridges which is unusual but possible (formation of right angles to other ridges) - must decide if this is part of the ridge path or possible distortion.

Question 26

Salil Chatterjee used the term EDGEOSCOPY to describe the examination and evaluation of the edges of ridges – briefly explain its relevance to the identification process:

Answer 26

Having an understanding of the relevance of edge shapes as third level detail can only enhance comparison and improve one’s ability to describe how an identification is carried out. The essence of friction ridge comparison is comparing shapes in sequence.

Question 27

Through heredity, certain traits are passed genetically from parent to child. Why are fingerprint details not inherited?

Answer 27

Due to Differential Growth - forces of pattern formation on the volar pad as opposed to a genetic connection. When the ridge characteristic is examined beyond the type, the smaller details such as relative pore location and ridge shape will always be different.

Question 28

Does a ridge ending that appears as a bifurcation in an impression have an impact on its significance?

Answer 28

No - clarity dictates our level of tolerance for discrepancy. Impressions are 2D and never a perfect recreation of the 3D friction ridge skin. Any variation will fall within limits of friction skin and are explainable.

Question 29

Does a ridge endnig in the delta area have the same value as a ridge ending in an open field of ridges?

Answer 29

No due to pattern force. Similar ridge characteristics may appear in similar shaped patterns.

Question 30

Are “white lines” permanent?

Answer 30

Once established they typically do not change, however, there is no underlying structure anchoring them in place. White line definition can increase with age or subcutaneous fatty deposit changes.

Question 31

In the context of fingerprint analysis what does the term “lateral distortion” mean?

Answer 31

Pressure distortion causing a lateral shift - movement - can also include disjointed friction ridge formations like double taps.

Question 32

Does the absence of third level detail prevent the examiner from forming and identification opinion, why not?

Answer 32

No it does not. Level two detail is sufficient to identify.

Question 33

List four factors that may affect the duration that a latent fingerprint will remain on a surface:

Answer 33

1. Substrate the impression was left on 2. Composition of the matrix 3. Humidity/Temperature 4. Exposure to the elements

Question 34

Explain the difference between identification and individualization:

Answer 34

Identification - the act or process of identifying - prove to be the same. Similarity of class characteristics. concluding the unknown originated from same source as known. Individualiazation - Two impressions originated from the same source to the exclusion of all others. Cannot say to the exclusion of all others because there's billions of people that have lived and not every friction ridge has been compared to eachother.

Question 35

Who conducted the 50K vs 50K study?

Answer 35

The Meagher, Budowle, and Ziesig Model - conducted by the FBI in conjunction with Lockheed Martin, Inc . The primary experiment conducted by Meagher and colleagues utilized AFIS computer algorithms to compare each of 50,000 fingerprint images (all left loops from white males) against itself and then the remaining 49,999 images in the database. The result of each comparison produced a score proportional to the degree of correlation between the two images. It is critical to note that all previous models possess calculations of individuality based on predicted minutiae arrangements; however, the scores in this model are a function of the AFIS algorithms and matcher logic.

Question 36

Who was the first researcher to use a probability model for fingerprint identification?

Answer 36

In 1892 Sir Francis Galton was the first to use a probability model for identification. It was unrealistic as it was built on the ability to predict minutaie dependent on surrounding ridges.

Question 37

Provide a brief summary on the use of probability models for fingerprint identifications.

Answer 37

Fingerprint minutaie are highly discriminating features - the more features shared between impressions = the less likely (probable) to randomly be observed elsewhere. Needs to be validated by further testing.

Question 38

Provide a brief explanation of why we are not using probability models for fingerprint identifications:

Answer 38

These models have not been validated. None of the models has been subjected to testing, which is the basic element of the scientific approach. (Scientific Method - observation, hypothesis formulation, experimentation, data analysis, and conclusion )

Question 39

Briefly outline the nature of Dr Itiel Dror’s research as it pertains to fingerprint identification:

Answer 39

Studied bias - contextual information influenced the decision-making processes. A great deal of work in cognitive science has focused on how humans determine similarity between two objects, and how expertise affects this computation. Experts likely learn to overcome this noise; as one expert put it, their job is to “see through the noise”.

Question 40

Briefly describe Dr. Cedric Neumann’s research as it pertains to fingerprint identification:

Answer 40

Dr. Neumann worked on Statistical Competition of Likelihood Ratios which is the validation and implementation of an operational tool to statistically assess fingerprint evidence. Found that when the number of minutaie in agreement increases then the less likely it would be to find a similar arrangement of features in another source on average.

Question 41

What is DNA?

Answer 41

Deoxyribonucleic acid (DNA) - Inside a nucleus of a cell is 23 pairs of chromosomes - each parent contributes half creating a distinct set of chromosomes in the offspring. Within each chromosome there are billion of base pair combinations resulting in natural variation through heredity - with the exception of identical twins.

Question 42

What other living things, besides humans, have DNA that is commonly of forensic significance?

Answer 42

Animals, plants, and some viruses

Question 43

What is “mtDNA” or “mitoDNA”?

Answer 43

Mitochondrial DNA - the mitochondria is the powerhouse of the cell. It consists of approximately 16.5 thousand base pairs structured in a loop. It is inherited singularly from the mother and does not have the same discriminating power as nuclear DNA. Can be particularly useful in missing persons cases to compare hair or bone from a decomposed body to a maternally related relative.

Question 44

Name four factors that will cause DNA degradation:

Answer 44

- Chemicals - Extreme heat - UV light - Bacteria

Question 45

Name sources of human DNA that you will commonly search for at a crime scene?

Answer 45

Blood Bone Dandruff Hair with the root/scalp cells remaining Fingernails/Fingernail scrapings Saliva Semen Vaginal secretions Fingerprints Particulate flesh, skin, or organs Nasal and ear secretions Sweat

Question 46

When dealing with a badily decomposed body, what would be the best source for DNA standard samples?

Answer 46

- Sample of deep muscle tissue - Bone - including marrow from a long bone or rib - Teeth - preferably a molar

Question 47

Describe the process for collecting and preserving a sample of liquid blood for DNA analysis:

Answer 47

Use a sterile swab to take a sample Air dry Package Seal separately

Question 48

A pair of work boots has been seized from a suspect. One boot has been positively linked to the crime scene; however, the suspect denies ownership of the boots. Is it possible to link the boots to the suspect?

Answer 48

Barefoot morphology of the inside of the shoe, cutting the footwear upper away as close to the insole as possible, then examining the insole. Comparison should be like to like or if another shoe insole is not available, a sock impression can be used. DNA from inside the shoe - sweat - as well as from the shoe laces - sloughed off skin cells from tying shoes.

Question 49

Toxicology Services of the National Forensic Laboratory Services will examine bodily fluids and tissues – what three general types of toxins can they identify?

Answer 49

Alcohol, Drugs, and Poisons

Question 50

In cases of death where complete toxicological general screen exams are required, list five exhibits that must be submitted:

Answer 50

Blood, Stomach Contents, Tissues (liver, brain, muscle), Urine, Vitreous Humour (jellylike tissue filling the eyeball behind the lens)

Question 51

Which RCMP form must be sumitted to the Forensic Assessment Centre when requesting the analysis of evidence?

Answer 51

Form C-414

Question 52

Describe how tape is used to collect hair and fiber evidence at a crime scene:

Answer 52

If DNA is required use a new roll of tape. Photographs. Clear adhesive tape is cut into 8-10 inch lengths. Hold opposite sides and lightly apply pressure onto the surface in question - repeat use until tackiness is reduced on that specific area. Secure to transparent plastic - with clean tape to ensure there is no loss of loose material. Numerous tapings from the same area can be placed on the same document protector so long as it denotes the specific area (front, back, seat). Separate backings are to be used for distinctly different areas - driver's seat of a car vs passenger seat of a car. Each document protector is sealed in their own exhibit bag/s. (If possible submit a sample of the fabric that was taped for comparison.)

Question 53

Describe Locard’s Principle of Exchange in your own words and how it applies to you as a Forensic Ident member:

Answer 53

When two things come into contact with each other they will leave behind a trace of themselves. Wearing PPE for self and preventing contamination of a scene. That there should be evidence on scene to find.

Question 54

Describe the procedure for taking fingerprint impressions from a deceased person.

Answer 54

If the deceased is recently dead - clean the area, lightly apply black fingerprint powder, gently smooth a sticky label over the powdered area from one side to the other - apply to document protector (C-216T). Denote "biohazard" if bodily fluids are removed onto the lifter. If the epidermis is too wrinkled - attempt photography - and to create better contrast add black powder to the finger. If unsuccessful - cast with Mikrosil and apply black powder to the cast - use tape to lift the dusted impression and place it on a transparency card. To inflate a wrinkled finger if the above does not work - tie a string beneath the distal phalange under the joint - have the pathologist inject water into the fingertip between the dermis and epidermis - too much water pressure will split the epidermis. If the skin has slipped off or is easily removed - flatten on surface and photograph with scale. If no detail present using oblique lighting - photograph the underside of the epidermis (ridges underneath are laterally correct) If the skin is de-gloving then it can be placed over the Forensic employees gloved hand and record the impression by coating with powder and rolling an adhesive label over the powdered area. If skin is de-gloved and wrinkled - consider flattening it between two glass plates and photographing. Loss of epidermis - photograph the dermal surface - double rows of papillae pegs can be used for comparison - very small amount of black powder can be added for contrast. Mummification - rehydrate the finger by soaking it in - fabric softner and water (check every few hours not extending more than 48 hrs), palmolive dishwashing soap and water (check every 4-6 hrs after soaking for 24 hrs - length of time to soak depends on extent of mummification) , Kodak Photo-Flo (Check every hour until epidermis is soft and pliable.)

Question 55

A person known to have an FPS number has died and you are unable to obtain their fingerprints. What should you do?

Answer 55

Advise on a C163 (death notification form) that the fingerprint cannot be obtained and the reason why. Send this to CCRTIS (Canadian Criminal Real Time Identification Services).

Question 56

List the recommended solutions that can be used to help restore the severely wrinkled or mummifed fingers of a cadaver:

Answer 56

- fabric softner and water (check every few hours not extending more than 48 hrs), - palmolive dishwashing soap and water (check every 4-6 hrs after soaking for 24 hrs - length of time to soak depends on extent of mummification), - Kodak Photo-Flo (Check every hour until epidermis is soft and pliable)

Question 57

Explain the string method for obtaining fingerprint impressions from the wrinkled fingers of a cadaver:

Answer 57

Tie a string beneath the distal phalange under the joint - have the pathologist inject water into the fingertip between the dermis and epidermis - too much water pressure will split the epidermis.

Question 58

A bullet has penetrated a window. Explain how it is possible to determine if the shot was fired from inside or outside of a building.

Answer 58

Depending on the type of glass it can be difficult to visually see, (windshield's are laminate glass and will present entry/exit in similar appearance). - Laminate glass will demonstrate an abrupt edge on the entry and the exit will have a sloping edge (coning effect). The displacement of glass and plastic laminate will travel in the direction of the bullet. - Plate glass windows - there is a coning effect on the exit which will be more distinct than on laminate glass. The coning effect is on the exit side of the glass. - Tempered glass windows – side window of a vehicle.

Question 59

Five 9mm bullets have penetrated a plate glass window. Explain how it is possible to determine the sequence of each hole – which was shot first, etc…

Answer 59

Examining the radial fractures can indicate which bullet was shot first as the first shot will create radial fractures from the bullet hole unfettered through the glass. Subsequent shots will typically create radial fractures that will stop when meeting an already established fracture line in the glass.

Question 60

When a piece of glass breaks there are usually minute, slightly curved, elevations or broken edges. What are the names of these stress marks and explain their forensic significance?

Answer 60

- Conchoidal Stress Fractures - Can assist in directionality of force applied to glass. Ridge lines are curving conchoidal fractures. The fracture in the glass will be at a right angle on the side opposite of where the force was applied, while the nearly parallel lines of the fracture will be visible near the side that the force was applied to. - Rib - Curved, rib shaped lines that form a wave-like pattern on the fractured surface - the concave side of the marks indicate the side that the force was applied to - Hackle marks - Are typically more defined than rib marks - found nearer the point of impact - appear as angular lines - indicate a strong impact. Radial pattern with lines running parallel to each other - are microscopic

Question 61

When National or Divisional Disaster Plans do not provide specific direction to Forensic Ident members, which document will provide necessary guidance?

Answer 61

Mass Casualty Management/Disaster Victim Identification Guide

Question 62

List two reasons why the victims of mass disasters must be identified:

Answer 62

- Investigation - Repatriation

Question 63

During the post-mortem examination, the pathologist informs you that the hyoid bone is fractured. What does this suggest?

Answer 63

Located in the neck - Can indicate strangulation when fractured.

Question 64

What is petechial hemorrhage and what does it suggest?

Answer 64

- Small red/purple spots on the sclerae (whites of the eyes) and conjunctivae (mucous membrane covering the front of the eye and lines the inside of the eyelids). - Petechiae can suggest asphyxiation as a potential cause of death.

Question 65

During an autopsy the pathologist refers to an “ante-mortem” injury. What is an “ant-mortem” injury?

Answer 65

Occurred "before death" - injuries that occurred when the individual was alive. May or may not be related to Cause of Death

Question 66

During the cursory external examination of a severe cut or wound on a deceased victim, a pathologist describes a number of superficial, shallow wounds accompanying the deeper, fatal incision. What do these shallow cuts suggest?

Answer 66

Hesitation marks.Victim building up the courage to inflict the injury that will cause death.