1. Fingerprints
T. Trimpe

2. Fingerprint Principles
ACCORDING TO CRIMINAL INVESTIGATORS, FINGERPRINTS FOLLOW 3 FUNDAMENTAL PRINCIPLES:
A FINGERPRINT IS AN INDIVIDUAL CHARACTERISTIC; NO TWO PEOPLE HAVE BEEN FOUND WITH THE EXACT SAME FINGERPRINT PATTERN.
A FINGERPRINT PATTERN WILL REMAIN UNCHANGED FOR THE LIFE OF AN INDIVIDUAL; HOWEVER, THE PRINT ITSELF MAY CHANGE DUE TO PERMANENT SCARS AND SKIN DISEASES.
FINGERPRINTS HAVE GENERAL CHARACTERISTIC RIDGE PATTERNS THAT ALLOW THEM TO BE SYSTEMATICALLY IDENTIFIED.

3. Fingerprint Classes Arch Plain arch Tented arch Loop Radial Loop
There are 3 specific classes for all fingerprints based upon their visual pattern: arches, loops, and whorls. Each group is divided into smaller groups as seen in the lists below.
Arch
Plain arch
Tented arch
Loop
Radial Loop
Ulnar loop
Whorl
Plain whorl
Central pocket whorl
Double loop whorl
Accidental

4. 60% of people have loops, 35% have whorls,
Interesting Info
Fingerprint Factoid:
60% of people have loops, 35% have whorls,
and 5% have arches
Did you know?
Dactyloscopy is the study of fingerprint identification. Police investigators are experts in collecting “dactylograms”, otherwise known as fingerprints.

5. Arches
Arches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present.
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.

6. Loops
Radius
Ulna
Left Hand
Loops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones, i.e. the bone the loop opening is facing towards.
L – Radial Loop
R - Ulnar Loop
L – Ulnar Loop
R - Radial Loop
Delta
X-Ray Imagine:

7. Whorls
Whorls have at least one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas. 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.

8. 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.

9. Identify each fingerprint pattern.? A B
Right Hand
Left Hand
Answer Key: A - Plain Whorl, B – Double Loop Whorl, C – Radial Loop, D – Tented Arch, E – Plain Arch C
Right Hand E D
Right Hand
Left Hand

10. Types of Fingerprinting - Latent
LATENT PRINTS - are fingerprint impressions secreted in a surface or an object and are usually invisible to the naked eye. These prints are the result of perspiration which is derived from sweat pores found in the ridges of fingers. When fingers touch other body parts, moisture, oil and grease adhere to the ridges so that when the fingers touch an object, such as a lamp, a film of these substances may be transferred to that object. The impression left on the object leaves a distinct outline of the ridges of that finger. These fingerprints must be enhanced upon collection and, because they serve as a means of identifying the source of the print, they have proven to be extremely valuable over the years in the identification of its source.

11. Types of Fingerprinting - Latent
Prints may be collected by revealing them with a dusting of black powder and then lifted with a piece of clear tape.
Magnetic powder can also be used to reveal latent prints and works on shiny surfaces or plastic baggies or containers
Some investigators use fluorescent powder and UV lights to help them find latent prints on multi-colored or dark surfaces.
Ninhydrin is a chemical that bonds with the amino acids in fingerprints and will produce a blue or purple color. It works well on paper or cardboard surfaces.
Types of Fingerprinting - Latent

12. Types of Fingerprinting - Plastic
PLASTIC PRINTS - are visible, impressed prints that occur when a finger touches a soft, malleable surface resulting in an indentation. Some surfaces that may contain this type of fingerprint are those that are freshly painted or coated, or those that contain wax, gum, blood or any other substance that will soften when hand held and then retain the finger ridge impressions. These prints require no enhancement in order to be viewed, because they are impressed onto an object and are easily observable.

13. Types of FingerPrinting - Patent
PATENT PRINTS - are visible prints that occur when a foreign substance on the skin of a finger comes in contact with the smooth surface of another object. These prints leave a distinct ridge impression that is visible with the naked eye without technological enhancement of any kind. The tried and true "blood on his hands" evidence is an example of patent prints recovered from a crime scene or scene of interest to investigators. These foreign substances contain dust particles which adhere to the ridges of the fingers and are easily identifiable when left on an object.
Types of FingerPrinting - Patent

14. Integrated Automated Fingerprint Identification System
IAFIS IS A NATIONAL COMPUTERIZED SYSTEM THAT ALLOWS FINGERPRINTS FOUND AT A CRIME SCENE OR OF A PERSON OF INTEREST TO BE COMPARED TO A DATABASE OF KNOWN FINGERPRINTS MAINTAINED BY THE FBI. IN ADDITION TO FINGERPRINTS, THE DATABASE ALSO CONTAINS CRIMINAL HISTORY INFORMATION ABOUT CONVICTED PERSONS, AS WELL AS MUGSHOTS, INFORMATION ABOUT TATTOOS OR DISTINGUISHING MARKS, PHYSICAL CHARACTERISTIC SUCH AS HEIGHT AND WEIGHT. IT IS ONE OF THE LARGEST FINGERPRINT DATABASES IN THE WORLD HOUSING THE PRINTS AND CRIMINAL HISTORY OF 70 MILLION CONVICTED PERSONS, AS WELL AS 34 MILLION CIVILIANS! THE COMPUTER GENERALLY TAKES LESS THAN AN HOUR TO GET POSSIBLE MATCHES FROM THE DATABASE. IN FACT, THE AVERAGE WAIT TIME IS ONLY ABOUT 27 MINUTES!