Chapter 8 Flashcards
What does the term ‘biometrics’ refer to?
Identification of individuals based on unique physical or behavioral characteristics.
What are the two groups of forensic biometrics?
Physiological: Fingerprints, iris patterns, DNA.
Behavioral: Voice patterns, gait.
Have two people ever been found with identical fingerprints?
No, even identical twins have unique fingerprints.
How many ridge characteristics are in an average fingerprint?
Approximately 150.
What are the most commonly encountered ridge characteristics?
Ridge endings, bifurcations, dots, enclosures.
How many ridge characteristics are necessary to identify a fingerprint?
between 8-12
When are fingerprints formed?
During fetal development, by the 10th week of gestation.
What is the purpose of friction skin ridges?
To provide grip and prevent slipping by increasing friction.
Where are the sweat gland pores located?
On the ridges of the friction skin.
Define minutiae.
the distinctive ridge characteristics of a fingerprint that are used to identify and compare fingerprints
Define ridge characteristics.
Features within a fingerprint
Define bifurcations.
Points where a single ridge splits into two ridges.
Define ridge endings.
Points where a ridge ends abruptly.
What are the three types of fingerprint impressions?
Latent Prints: Invisible, caused by sweat/oils.
Plastic Prints: Impressed into soft materials like wax.
Visible Prints: Made by transferring a colored substance.
What are the three main ridge patterns and their frequencies?
Loop: 65-70%.
Whorl: 25-30%.
Arch: 5%.
What is AFIS?
Automated Fingerprint Identification System
What does sublimation mean?
The process where a solid changes directly to a gas without becoming a liquid.
In which order should chemical treatments be performed to visualize latent prints?
Iodine fuming
Ninhydrin
Super glue fuming
Physical developer
When is physical developer most useful?
For porous surfaces, especially after other treatments.
When is ninhydrin most useful?
On porous surfaces like paper; reacts with amino acids.
When is super glue fuming most useful?
On non-porous surfaces like glass or metal.
When is iodine fuming most useful?
On porous or semi-porous surfaces like paper; temporary results.
What are the steps in the ACE-V process?
Analysis
Comparison
Evaluation
Verification
