1. Fingerprints

2. Summary What are fingerprints? How are fingerprints analyzed?
How are fingerprints collected?

3. What are fingerprints? Friction Found on
Composed of (hills) and (furrows)
Black = Ridges
White = Valleys

4. What are fingerprints? Develop in Pattern based on , detail somewhat
Identical twins have fingerprints

5. History of Fingerprints
Long history of fingerprints as signature
Criminal identification first done by a system of called .
Alphonse anthropometry system used body measurements to identify an individual

6. History of Fingerprints
Sir invented a system for fingerprints
Allowed fingerprint records to be
Based on , so matching one print would be

7. How are fingerprints analyzed?
Categorized by and

8. How are fingerprints analyzed?
Patterns

9. Arches
Arches are the simplest type of fingerprints that are formed by ridges that of the print and .
Tented Arches
Similar to the plain arch,
but has a spike in the center.
Spike or “tent”
Plain Arch
Ridges enter on one side and
exit on the other side.

10. Loops
Loops must have one delta and one or more ridges that These patterns are named for their positions related to the radius and ulna bones.
Radial Loop (Right Thumb)
Loop opens toward the left or the radial bone.
Ulnar Loop (Right Thumb)
Loop opens toward right or the ulna bone.
Delta
NOTE: On the left hand, a loop that opens to the left would be an ulnar loop, while one that opens to the right would be a radial loop.

11. Whorls
Whorls have at least one ridge that makes (or tends to make) a . They also have at least . If a print has more than two deltas, it is most likely an accidental.
Central Pocket Whorl
Plain Whorl
Draw a line between the two deltas in the plain and central pocket whorls. If some of the curved ridges touch the line, it is a plain whorl. If none of the center core touches the line, it is a central pocket whorl.

12. Whorls – Part 2 Double Loop Whorl
Double loop whorls are made up of any two loops combined into one print.
Delta
Accidental Whorl
Accidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories.

13. How are fingerprints analyzed?
Minutiae – points where
Bifurcation
Ridge Ending
Dot
Island

14. Ridge Characteristics
Use these characteristics as points of identification when comparing fingerprint samples. The more points you can find in common, the better the match!

15. Ridge Characteristics
Crossover
Core
Bifurcation (fork)
Ridge ending
Island
Delta
Pore
Scar
EXAMPLE

16. compares the location of these minutiae.
Fingerprints
compares the location of these minutiae.

17. Fingerprint Identification
When minutiae on two different prints match, these are called or
There is for the number of points of identification required for a match
However, the United Kingdom requires a minimum sixteen points while Australia requires twelve.
( )
AFIS is a computerized system capable of reading, classifying, matching, and storing fingerprints for criminal justice agencies. Quality latent fingerprints are entered into the AFIS for a search for possible matches against the state maintained databases for fingerprint records to help establish the identity of unknown deceased persons or suspects in a criminal case.

18. There are 3 types of fingerprints
1. – left by
Does not need processing

19. There are 3 types of fingerprints
2. – (butter, putty, tar, etc.)
Does not need processing

20. There are 3 types of fingerprints
3. – requires to make visible and suitable for analysis

21. What are the invisible components?
Fingerprints > Analysis
What are the invisible components?
Multiple secrete onto fingers, palms, etc.
Sweat contains:
Inorganic ions (Na+, Cl -)
Proteins, amino acids
Lipids
Other

22. Development and Collection:
Fingerprints > Analysis
Development and Collection:
Scene or Lab?
No rule:
Fingerprint after development (scene or lab)

23. Physical Development: Dusting
Fingerprints > Analysis
Physical Development: Dusting
Apply to latent print or area.
Powder to print.
Magnetic Brush
and Powder
Brush and Powder

24. Chemical Development:
Fingerprints > Analysis
Chemical Development: 1.
No longer used (messy, not sensitive)
Silver reacts with Cl - ions in print

25. Chemical Development:
Fingerprints > Analysis
Chemical Development: 2.
Iodine sublimes (solid → gas)
Iodine reacts with lipid components; becomes trapped in the print.
Fuming wand or chamber
Dirty Brown Color

26. Chemical Development:
Fingerprints > Analysis
Chemical Development: 3.
Reacts with amino acids; purple color
Painted or sprayed on area
Heated to react

27. Chemical Development:
Fingerprints > Analysis
Chemical Development: 4.
Fumes with heat or base (NaOH)
Fumed in cabinets
Off-white print

28. Collection of prints: : Tape placed over developed print
Fingerprints > Collection
Collection of prints: :
Tape placed over developed print
Tape then placed on white card.

29. Collection of prints: Sometimes a photograph will be the
Fingerprints > Collection
Collection of prints:
Sometimes a photograph will be the