1. Fingerprints
Definition: raised portions of skin covered in sweat that when pressed against a surface creates an impression of those friction ridges. (Sweat is a combination of H2O, dirt, and oils.)
Unit #3

2. Unit Objectives
At the conclusion of the unit, students will be able to:
understand the history of fingerprints;
define fingerprints;
discuss in detail the method of how fingerprints are created;
classify prints according to level I and II;
discuss the usages of fingerprints; and
discuss the process of AFIS.

3. Fundamental Rule #1
A fingerprint is an individual characteristic; no two fingerprints have yet been found to possess identical ridge patterns.

4. Utilization of Fingerprints
Identification in pottery and documents. –using either thumb, finger, or palm print.

5. History of Fingerprints
See handout

6. Fingerprints remain constant through an individual’s life… Why?
Fundamental Rule #2
Fingerprints remain constant through an individual’s life… Why?

7. Formation and Anatomy How do fingerprints form?
FPs are formed during the 10th week of gestation at the stratum Germinativium (basal) (5th and lowest layer)

8. Volar Pads-opposing side of fingernails
Volar Pads-opposing side of fingernails. When volar pads shrink, FP’s begin to form. Ridges are created perpendicular to the direction of stress. Volar pad structure leads to specific class: round -> whorls flatter -> arches

9. Henry Classification
Characteristics are named after general appearances
Three levels of classification
Level I – General Categories
Level II – Friction Ridge Minutiae
Level III – Unclassifiable features

10. Fundamental Rule #3
Fingerprints have general pattern classifications such as arch, loop, and/or whorl that allow for identification.

11. Deltas and Cores

12. Level I: Pattern Classification
Loops
Percentage of population
Bases of Categories

13. Level I: Pattern Classification
Arches
Definition: have friction ridges entering on one side, rises in the center and exits in the opposite direction of entry
Percentages

14. Level I: Pattern Classification
Whorls
Definition: pattern with two deltas causing the ridges to swirl around a center
Categories of Whorls

15. Level II – Friction Ridge Minutiae
Small individual markings within a Level I print.
Ten FR minutiae that help fingerprint examiners compare unknown prints to known.

16. Bifurcation Bridge FR diverges from one ridge to two continuous ridges
FR connects two adjacent FR

17. Core Delta The very center FR of either a ____ or ____
A triangular structure that causes other FR to change direction

18. Crossover Dot Two FR intersect to form a chromosomal- like structure
A very short and wide FR located between two adjacent FR

19. Double Bifurcation Enclosure Eye
One FR diverges twice resulting in three FR
Enclosure
One FR diverges, creates an opening, and then re-enters into the same FR
Eye
An enclosure with a dot

20. Hook
On FR diverges into two FR resulting in one continuous ridge and one short ridge
Short Ridge
A short FR that is discontinuous

21. Island Ridge Ending A ridge between two adjacent FR
The Termination of a FR

22. Triple Bifurcation Specialty
The divergence of one FR into four continuous ridges
Specialty
A unique minutiae pattern that cannot be categorized

23. Level III Classification
Pore identification

24. Types of Crime Scene Prints
3 categories
Plastic or Indented
3D fingertip impressions in a soft substance
Mediums: wax, putty, clay or drying paint

25. Patent Visible prints to the naked eye
Medium: bloody FP on a countertop

26. Latent
Invisible FP requiring techniques of recovery
Most common type

27. Prints are divided into two subcategories
Porous
Non-porous

28. Search Techniques for CS Prints
Technique is dependent on?
What is the order to look for prints?
Factors Affecting Visibility
Surface
Physical condition of print owner
Lighting angles
Heat
Duration from print to discovery

29. Factors Affecting Duration of Prints Remaining:
Weather
Air Currents
Humidity
Quality of Prints Affected
By:
Finger contact
Pressure

30. Type of Print and Surface
Powdering
Type of powders used
Instrumentation for powder application
Types of powders
Lifting Techniques

31. Chemical Processing Location?
Crime Scene or Laboratory?
Chemicals react with minerals and organic matter of the print
Perspiration

32. Types of Chemical Techniques
Physical Development
Small Particle Reagents
Used on: paper, cardboard, new, rusty, and galvanized metal, bricks, rocks, concrete, plastic, vinyl
Chemical Development
Ninhydrin Reacts with?
Iodine Fuming Reacts with?
Cyanoacrylate Fuming Reacts with?

33. ACE-V
Analysis
Comparison
Evaluation
Verification

34. Analysis and Identification
Comparison and recognizing of difference between the minutiae of known and unknown prints
Focus on 3 different levels of details
Level I
Level II
Level III

36. AFIS Automated Fingerprint Identification System
Searches for prints…does not ID them
1980
Process
Cons to AFIS
Prints of poor quality can cause examiner to guess on the pattern classification
Poor prints can also lead to a large number of candidates
Three levels of AFIS

37. IAFIS Integrated AFIS FBI data base
Largest biometric database in the world
Data includes: mug shots, scars and tattoos, height and weight, aliases
27 minutes to 2.5 hours to process