1. Fingerprints

2. History 3000 years ago… Chinese used fingerprints for legal papers
1880 Henry Fauld –first to use FP to ID criminals
1897 Sir Edward Richard Henry-
-developed Henry classification
- based on all 10 prints
- number/location of whorls

3. Skin Epidermis- outer layer, no blood supply
Dermis-internal layer- sweat glands that produce water, salts, oils
Papillae- at boundary of dermis and epidermis
Prints- made of mostly water, salts, oil

4. Cross Section of Skin

5. AFIS
Automated Fingerprint Identification System

6. Matching points Also known as: - Minutiae - Galton points
Based on types of ridges
Match ridges from a known print with an unknown print.

7. Types of Ridges Ending ridge Bifurcation (fork) Enclosure Short ridge
Dot
Eye (island)
Bridge
Double bifurcation
Trifurcation

8. Fingerprints Friction ridges help human grip things
Identical twins have different fingerprints.
Fingerprints do not change over your lifetime.
Scarring, etc can be used for ID

10. Deltas Delta- ridge that diverges Loops have one delta
Whorls have 2 deltas
Arches do not have deltas.

11. Types of Fingerprints
1. Arch
2. Whorls
3. Loops

12. Arches
Arches (no core or delta)
Plain
Tented

13. Whorls One or more ridges make complete circles
Two deltas and at least one core

14. Loops
Radial- loop opens to thumb
Ulnar - loop opens to pinky side

15. Pores Found randomly along the ridges Produce sweat
Chemicals in sweat make the fingerprint that is left behind
Pore location can be used to identify the person.

16. Process of Identification
Get prints of all ten fingers from a person in question (suspect, victims, police, etc..)
Ways to get the 10 prints
Traditional ink and paper
Roll colorless chemical on treated paper… chemicals react and the print becomes visible (newer)
Live scan: roll prints on glass over video camera. Image is turned into digital information (newer)

17. Quality of prints Quality affected by:
Skill and experience of person taking the print
Cooperation of person giving the print
Damaged skin on people who work w/ their hands
Rigor mortis
Decomposition, burned bodies

18. Types of Prints 1. Visible (patent) 2. Plastic 3. Latent Bloody prints
Tacky paint
Putty
Clay
Soap
3. Latent
Invisible
Deposit sweat and oil

19. Methods to Develop Prints
Black powder
Magnetic powder
Iodine fuming (good on paper)
Silver nitrate
Ninhydrin ( for prints on paper)
Super glue (=cyanoacrylate)
Stickyside ™powder

20. Locating prints Shine flashlight at oblique angle
Gloves may leave impression
Less obvious places: under toilet seats, toilet handles, tabletops, dresser drawers, surface of dinner plates, back of rearview mirrors, trunk lids of cars
Use someone familiar w/ scene to tell if anything is different about the area

21. Equipment Ultraviolet light (black light) Laser Alternate light source
Some substances will glow when exposed to UV
Ex. LSD– bluish-white
Ex. Certain fingerprinting powders glow under UV
Laser
Alternate light source
powerful light causes some materials to fluoresce or luminesce

22. Daubert Hearings
Fingerprint experts need to convince a judge that the methods used are valid.
Daubert standards:
Has the expert’s scientific method been tested?
Has the expert’s method been the subject of peer review and testing
What is the actual or potential rate of error?
do other scientists generally accept the expert’s methods?

23. Odds and Ends
If AFIS is used to locate a match, the final identification must be done by a human
Palm prints can also be used
Latent prints can often be developed years later as long as they don’t become wet
Fingerprints made from soot, insulation, face powder are easily destroyed
Prints made from blood, ink, oil can last longer