1. Fingerprinting
Part II

2. Primary classification: The Henry
This classification method was developed in 1899 as a way to classify 10 card fingerprint records.
Allows for quick exclusion of candidates for a crime.
The system assigns each finger a number based on where it is located (1 for thumb, 5 for pinky) AND assigns a point value to each finger. If a finger has a whorl, then it gets those points, if not, then it gets 0 points.
These numbers are then plugged into an equation which gives the 10 card a fraction value between 1/1 to 32/32.
This method has been influential in the development of AFIS.

3. The Henry Each finger is given a point value
Using a 10 card print, examine each of the prints as to whether they are loops, arches, or whorls.
If there is a whorl present, then those points are given for that finger.

4. Primary classification
The presence of a whorl, earns the value for that finger.
Insert the number point for each finger that has a whorl and substitute into this equation:
The sum of the even finger values are calculated and placed in the numerator of the fraction. The sum of the odd finger values are placed in the denominator.
This number is your primary classification number
right right left left left
index ring thumb + middle + little
right right right left left
thumb + middle + little index + ring

5. Your turn:

6. Secondary classification
Fingerprint minutiae are examined.
Generally courts will accept 8-12 points of similarity on one print.
This is considered an individual classification.
This is what AFIS (Automated Fingerprint Identification Systems) does – it matches minutiae points.
The latest technology creates a mathematical polygon based on X number of minutiae identified. This supposedly is less vulnerable to distortion than a typical examination for minutiae.

8. Types of Fingerprints
There are 3 types of prints that investigators look for at crime scenes:
Patent fingerprints—visible prints transferred onto smooth surfaces by blood or other liquids
Plastic fingerprints—indentations left in soft materials such as clay or wax
Latent fingerprints—made visible by dusting with powders or the use of chemicals 1 2 3

9. Developing Latent Prints
Developing a latent print requires substances that interact with skin secretions that cause the print to stand out against its background. It may be necessary to attempt more than one technique, done in a particular order so as not to destroy the print.
Powders—adhere to water and fatty deposits (from sweat and oil). Choose a color to contrast the background.
Iodine—fumes react with oils and fats to produce a temporary yellow brown reaction.

10. Developing Latent Prints
Ninhydrin—reacts with amino acids to produce a purple color.
Silver nitrate—reacts with chloride to form silver chloride, a material which turns gray when exposed to light.
Cyanoacrylate—“super glue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit.
In most labs lasers and alternative light sources can be used to view latent fingerprints.

11. Iodine fuming

12. Ninhydrin Fingerprint

13. Cyanoacrylate (superglue)
**View movie clip from BHC 2

14. Other Prints Ears—shape, length and width
Voice—electronic pulses measured on a spectrograph

15. Other Prints Lips—display several common patterns Short vertical lines
Short horizontal lines
Crosshatching
Branching grooves

16. Other Prints
Bite marks are unique and can be used to identify suspects.
We will investigate this more in unit 10.

17. Other Prints
The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.

18. Fingerprint Forensic FAQs
Can fingerprints be erased?
Only temporarily; they will grow back if removed with chemicals
John Dillinger attempted to remove his fingerprints with acid, but they grew back as the skin healed/regenerated.
Is fingerprint identification reliable?
Yes, but analysts can make mistakes
In 1995 as part of an experimental test, 156 fingerprint examiners were given several sets of prints to analyze. 1 in 5 made at least one false positive.
Can computers perform matches in seconds?
No, but the FBI’s Integrated Automated Fingerprint Identification System (IAFIS or AFIS) can provide a match in 2 hours. However prints are generally not compared out of state lines unless there is reason to believe that is necessary. (this can take longer).

19. Any questions?

20. Activity: Prepare a 10 card on your partner.