Fingerprints and Exhibits Flashcards
What is a fingerprint?
An impression of the friction ridges of all or any part of the finger.
What are the two types of human friction ridge skin?
- Palmar – bottom of hands
- Plantar – bottom of feet
What is the uniqueness of human friction ridge skin?
Each individual possesses a unique arrangement of friction skin; no two fingerprints are the same.
How persistent is human friction ridge skin throughout a person’s lifetime?
The sequence of the ridges and the arrangement of the minutiae do not change, except for injury.
At what stage of development are fingerprints fully formed?
By the time a fetus is 6 months old.
What percentage of a deposited fingerprint is composed of water?
Almost 99%.
List the functions of skin.
- Acts as a container for the skeletal structure and internal organs
- Provides sensory input about external conditions
- Eliminates waste products through sweating
- Allows for the ability to grasp surfaces firmly
What are the two distinct layers of friction ridge skin?
- Epidermis (top)
- Dermis (bottom)
What is the generating layer of the epidermis?
The bottom layer of the epidermis adjacent to the dermis where new cells are formed.
What are the three levels of detail in examining fingerprints?
- Level 1 - Pattern
- Level 2 – Ridge Characteristics
- Level 3 – Pores, Ridge Edges
What are the three basic fingerprint patterns?
- Loop
- Whorl
- Arch
What is the average number of ridge characteristics in a finger?
As many as 150 ridge characteristics.
What is an incipient ridge?
Friction ridges that did not fully form; may appear shorter and thinner.
What does the ACE-V method stand for?
- Analysis
- Comparison
- Evaluation
- Verification
What is the purpose of the analysis step in the ACE-V method?
To assess an unknown impression to determine suitability for comparison.
What is the evaluation step in the ACE-V method?
An examiner assesses the value of the details observed and reaches a conclusion.
What are the possible conclusions in the evaluation step?
- Identification/individualization: from the same source
- Exclusion: not from the same source
- Inconclusive: unable to identify or exclude
What are the types of fingerprint impressions found at crime scenes?
- Latent – not visible to the naked eye
- Visible – readily visible
- Moulded – retains 3D shape
What is the primary method used for making latent prints visible on nonporous surfaces?
Powdering.
What is the correct technique for powdering a fingerprint?
Brush in the direction of any ridges that begin to appear and build powder onto ridges.
What should be included when marking a fingerprint?
- Circle around the print
- Use letters and numbers sequentially
- Date and initials
- Scale close to the print
What is the purpose of photographing a fingerprint?
To document the print with overall, mid-range, and close-up photos.
What is the purpose of a lift card in fingerprinting?
To document the details of the lifted fingerprint.
What are the packaging requirements for exhibits in fingerprinting?
- New unused packaging
- Avoid contamination
- Secure transport
What is the importance of wearing PPE when collecting exhibits?
To avoid contamination of the exhibits.
True or False: The conclusion reached in fingerprint analysis is always objective.
False.
