FKA 2 Flashcards
Describe the nature of Dr. William Babler’s research as it pertains to the prenatal development of the friction skin
It focussed on the understanding of the prenatal morphogenesis of the dermatoglyphic traits and their relationship to birth defects
What is the difference in structure between the basal cells and the primary and secondary ridges
There is less keratin in the primary ridges than in the secondary ridges.
The secondary ridges display well-developed cellular projections extending deep into the dermis (dermal papillea).
what are meissner corpuscles
Nerve ending contained in the dermal papillae; establishes the sense of touch the dermal surface
What is the primary cell type of the epidermis
Keratinocytes
What prevents the migration of cells from the basal layer of the epidermis
Hemidesmisomes - fibres connecting the basal layer to the basement membrane zone
What phenomenon ensures that basal cell proliferation is stimulated and inhibited in a coordinated matter
Cell communication
According to Dr Okajima what are 2 subtle changes to the friction skin surface as a person ages
Flattening of the ridges and loss of elascticity
What causes the puckering of ridges during the formation of a scar an injury site
Contraction of the dermis at the base of the wound/injury
Why is it important for a fingerprint expert to understand the physical limitations of the friction skin
In order to understand the physical limitations of the skin when conducting comparisons.
According to Dr. Kimura’s research, identify when the prominent flexion creases develop
8 weeks: Thenar creases
9 weeks: Finger creases
10 weeks: toe creases
11 weeks: distal transverse crease
13 weeks: Proximal transverse crease
What is meant by volar pad regression
The volar pad is not so much shrinking but is overtaken by the faster growth of the surrounding skin
According to Dr Okajima, Chacko and vaidya’s research, when do dermal papillae begin to form and when do they stop
Begin to form at 23 weeks and become more complex through fetal development. Continues onward into adulthood
The onset of cellular proliferation, which begins primary ridge formation, occurs in which 3 distinct areas
1) Apex of the volar pad (core)
2) Tip of the finger near the nail bed
3) Distal inter-phalangeal flexion creases (below deltas)
Name the three main areas of the palm
1) thenar
2) hypothenar
3) interdigital
Name the three groups of flexion creases found in the palm
1) major
- distal (top)
- proximal (middle)
- thenar (bottom)
2) minor
- starburst (by thumb)
- bracelette (crossover/inter-locking)
- by thumbs/finger creases
3) secondary
- cross hatch (horizontal/vertical creases)
- most evident in thenar pad
Name the major palmar flexion creases
1) thenar/radial
2) proximal transverse
3) distal transverse
Can Palmer flexion creases be used for personal identification
Yes. These creases are both unique and persistent and can be used for identification. They should be used with friction ridges for comparisons
What are the basic premises upon which fingerprint identification is based
1) Established before birth
2) Persistent throughout life
3) Unique to very small areas
4) Classifiable
What is the philosophy of fingerprint identification as stated in the I F I M
Identification is established through the agreement the friction ridge formations in sequence, Having sufficient uniqueness to identify.
Name and summarize the methodology you use to identify a fingerprint
ACE-V - Analisys, Comparison, Avaluation and verification
Analyze: This is a qualitative-quantitative evaluation of the fingerprint taking into consideration: substrate, matrix, development medium, digit determination, distortion, deposition pressure, pattern type and clarity. At this stage the examiner determines the FP’s suitability for comparison.
Comparison: Side-by-side, ridge to ridge, in sequence comparison of all the available detail in the unknown.
Evaluation: At this stage two questions must be answered: is there agreement in friction ridge detail between the unknown and the known? Is there a sufficient uniqueness to identify? An opinion is reached.
Verification: An independant examiner repeats the process without knowing the opinion reached by the first examiner (blind)
What is the purpose of the analysis stage of ACE-V?
To determine if the impression is suitable for comparison.
There are three levels of detail which can be observed in the fingerprint impression. Describe each level and explain it significance to the identification process
1st - overall ridge flow; friction ridges visible, core, Delta and pattern tape
- cannot identify based on first level detail, but can exclude
2nd - ridge paths, ridge features, incipient ridges. Spatial locations of features, scars and creases.
- can identify based on second level detail
3rd - size and shape of the ridges, pores and pore locations
In friction ridge analysis terms, what is vestige
A group of ridges that run parallel to each other and end abruptly at right angles/90° to one another into the surrounding ridges. Typically found in the the thenar area of the palm
Salil Chatteejee used the term _____ To describe the examination and evaluation of the edges of friction ridges. Briefly explain its relevance to the fingerprint identification process
Edgescopy: Method of identification through the examination of the unique details and characteristics found along the edges of individual fingerprint ridges
Through heredity, certain traits are passed genetically from parent to child. Why then are fingerprint details not inherited
Heredity can affect things such as pattern type, however, it cannot affect the random formation of friction ridges (stresses, noise, random pressure, random timing, random growth)
Does a ridge ending that shows as a bifurcation and vice versa have an impact on their significance
Any differences must be understood, taking into consideration the clarity and/or distortion of the impression. The examiner must ask if there is a reasonable explanation for the difference in appearance.
Does a ridge ending in the Delta area have the same value as a ridge ending in the midst of an open field of ridges
No, a ridge ending in the Delta area will hold a lower value due to pattern force; ridge endings are more common in the areas of deltas
Are white lines to be considered as permanent
No, white lines are not permanent, although they may come and go over time
Explain the term lateral distortion as a pertains to fingerprint comparison
When a finger is in contact with the surface and there’s movement. This movement can cause smearing, feathering, shadowing, sliding, twisting etc.
Does the absence of third level detail Prevent the examiner from affecting an identification and why
No, third level detail does not prevent identification as third level detail represents the intrinsic detail of friction ridge shape and size, including pores and pore location and may not be reproduced the same between latent and impressions
List four factors that may affect the duration that a latent fingerprint will remain on a surface
1) Environment (rain, snow, light, indoors, outdoors)
2) Substrate
3) Matrix
4) temperature (hot/cold)
Explain the difference between identification and individualization
Identification is the opinion that the questioned impression was made by the known source. Individualization is an inference that two impressions originated from the same source.
Who conducted the 50 K versus 50 K study
Federal Bureau of investigation (FBI)
Who was the first researcher to use a probability model for fingerprint identification
Sir Francis Gaulton (1892)
Provide a brief summary on the use of probablity models for fingerprint identifications
There is no model that has ever been put forth that has been validated due to the low accuracy of the data they provide. Although numerous models have been proposed over the years, the data that they produce is inconsistent. As computer technology continues to develop, the ability to create a working model will be exponentially more feasible
Briefly outline the nature of Dr. Itiel Dror’s Research as a pertains to fingerprint identification
Dr Itiel Dror is a contemporary researcher who has published articles on cognitive bias and human factors related to visual perception in fingerprint identification, as well as other expert opinions
Briefly outline the nature of Dr. Cedric Neumann’s research as it pertains to fingerprint identification
Quantifying the weight of fingerprint evidence through:
- statistical computation
- ratios involved in configurations on minutiae
- sufficiency
What is DNA
DNA = Deoxyribonecleic Acid
Is the blueprint of living things
What other living things, besides humans, have DNA that is commonly a forensic significance
Animals and plants
What is MTdna. or Mito DNA
Mitochondrial DNA; small circular chromosome found inside mitochondria. These organelles are passed almost exclusively from mother to offspring through the egg cell
Name four factors that will cause DNA degradation
1) UV
2) heat
3) bacteria (moisture)
4) Chemical exposure
Name five sources of human DNA that you will commonly search for at a crime scene
1) blood
2) saliva
3) Semen
4) vaginal fluid
5) epithelial skin cells
When dealing with a badly decomposed body, what would be the best source for DNA samples
Bone, teeth or deep muscle tissue
Describe the process of collecting and preserving a sample of liquid blood For DNA analysis
1) Sterile swab and sterile water
2) Air dry
3) package in paper
4) Seal
5) label
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?
Yes.
1) DNA
2) depending on the age of the boots (new/rarely worn, older-worn) it is possible to obtain a foot impression from the inside of the boot.
In a criminal investigation, toxicology services of the crime lab will Examine bodily fluids and tissues. What three general types of Toxins could they identify
1) alcohol
2) drugs
3) Other substances; chemicals, poisons
List five exhibits which must be submitted in cases of death were a complete toxicological general screen exam is required
1) blood; cardiac and peripheral
2) urine
3) liver
4) stomach
5) Vitreous humour
Which RCMP form must be submitted to the forensics lab when requesting evidence analysis
C 414
Describe how tape is used to collect hair and fibre evidence at the crime scene
1) Please tape sticky side down on the surface in which the hair and fibres are present
2) remove tape and secure to clear acetate
3) write the file number, date, time, initials of person lifting and white area/surface that was being lifted from
Describe in your own words locards principle of exchange and how it applies to you as a forensic identification member
Every contact leaves a trace. This is the idea that every time we interact with our environment we are leaving behind physical evidence in the form of hairs, fibres, epithelial cells ect and also taking away physical evidence on ourselves in the same manner.
Describe the procedure for taking fingerprint impressions from a deceased person
The fingers are straightened to the best of the ability, Ink is placed on the fingers, a white label is rolled across the finger and then placed on either a clear acetate, a C- 216 or a combination of both
A person known to have an FPS number has died and you were unable to obtain their fingerprints. What should you do
Complete form C-163 and explain why fingerprints were not obtained
List the recommended solutions that can be used to help restore the severely wrinkled or mummified fingers of a cadaver
1) diluted fabric softener
2) diluted dishwashing solution
3) physical developer
Explain the string method of obtaining fingerprint impressions from the wrinkled fingers of a cadaver
Wind a string around the bottom of the finger and wind it upwards towards the top flange of the finger. Fill a hyper dermic needle with saline solution and fill the fingertip. Ink the fingertip and attempt to take impressions using standard practises for cadavers
A bullet has penetrated a window. Explain how it is possible to determine if the shot was fired from the inside or outside of the building
When a bullet is fired through glass, the Side opposite of the impact will have a crater
5, 9mm bullets have penetrated a plate glass window. Explain how it is possible determine the sequence of each hole, which was the first shot
When a shot is fired into glass, fractures will usually form around the point of impact. Each subsequent shots fired will create fractures, however the subsequent fractures will not cross through another fracture; it will stop at it. Therefore, it is possible to determine which shot was likely fired first, however, less likely to determine the entire five shot sequence, depending on the sequence
When a piece of glass breaks there are usually Minute, slightly curved, elevations or broken edges. What are the names of the stress marks and explain their forensic significance
The conchoidal fractures. They can indicate which side the pressure was exerted on causing the glass to break. They occur at a right angle to the force
When national or divisional disaster plans do not provide specific direction to forensic identification members, which document will provide the necessary guidance
RCMP FIS disaster procedures manual
List two reasons why the victims of mass disasters must be identified
As part of the investigation and for the repatriation of human remains
During the course of a post Mortem examination the pathologist informs you that the hyoid bone is fractured; what could this suggest
Possibility of strangulation
Describe the petechial hemmorhage and what it may suggest
Pinpoint red marks on the eyes which is indicative external obstruction of the airways, hanging strangulation etc. It is caused by the rupturing of Capillery in the eyes due to the increased pressure of the head due to the airway being obstructed
During an autopsy, the pathologist makes reference to a ante-mortem injury. What is the pathologist referring to
Ante: meaning pre are injuries caused prior to death.
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 could the shallow cuts suggest
These wounds are referred to as hesitation wounds common in cases of self-inflicted injuries; suicide and are near the fatal wound site
