t. trimpe 2006 & bertino - mrs....

T. Trimpe 2006 & Bertino

Fingerprinting has it’s roots in the early 1800s when a professor of anatomy at the University of Breslau first wrote a paper discussing fingerprint patterns. However, it wasn’t until years later when a man by the name of Francis Galton published a book discussing the matter that it was used to identify individual persons. Sir Francis Galton

A Brief History

Timeline

• 1823 Jan Purkyne publishes thesis on fingerprint patterns.

• 1880 Dr. Henry Faulds publishes his article on the subject in a

science magazine and offers his ideas to the London police. The

idea is rejected.

• 1892 Sir Francis Galton publishes a statistical model of fingerprint

analysis and discusses his theory that it could be used in forensic

science.

• 1892 An Argentine police officer makes the first criminal fingerprint

identification in a murder case.

• 1901 The UK Fingerprint Bureau is created in Scotland Yard.

Forensic Science: Fundamentals &

Investigations, Chapter 6

4

Historical Development

1. 3rd century B.C. in China—oldest known

documents

2. Ancient Babylon (1792-1750 B.C.)—fingerprints

pressed into clay tablets marked contracts

3. 1684—Dr. Nehemiah’s paper describes the patterns

on human hands, including the presence of ridges

4. 1788—Johann Mayer noted that the arrangement of

skin ridges is never duplicated in two persons


Investigations, Chapter 6 5


5. 1823—Jan Evangelist Purkyn describes nine

fingerprint patterns

6. 1856—Sir William Herschel (right) began the

collection of fingerprints and noted they were

not altered by age

7. 1883—Alphonse Bertillon created a way to

identify criminals that were repeat offenders



6


8. 1888—Sir Francis Galton (r) and Sir Edmund

Richard Henry developed the fingerprint

classification system still used in the US and Europe

9. 1891—Iván (Juan) Vucetich collected all ten fingerprint impressions and noted measurements

10. 1896—Sir Henry, with two colleagues, created a system that divided fingerprints into groups. All ten fingerprints are imprinted on a card (called a ten card) along with other notations

What Is a Fingerprint?

The skin on our fingers are made up

of many ridges of skin that are created

when we are still in our mother’s womb

at 10 weeks gestation. They remain the

same for the rest of our lives, even

surviving injury if not too severe. Each of

the ridges connect to other ridges,

forming a pattern that is unique to all

others. No two people in the world have

exactly the same print. This uniqueness

is used in many forensic cases to solve

crimes, as some of the most common

evidence found at a crime scene are

fingerprints.

Fingerprints on

each hand are

different. Can

be similar but

not mirror

images.



8

What Are Fingerprints?

• All fingers, toes, feet, and palms are

covered in small ridges

• Ridges help us grip objects

• Ridges are arranged in connected units

called dermal, or friction ridges

• Fingers accumulate natural secretions

and dirt

• Fingers leave/create prints on objects we

touch

9

Structure of Skin

The imprint of a fingerprint consists of natural

secretions of the sweat glands that are present in

the friction ridge of the skin.

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. (Individual evidence)

• 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.

Fingerprint Classes

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

Interesting Info

Did you know?

Dactyloscopy is the study of fingerprint identification.

Police investigators are experts in collecting

“dactylograms”, otherwise known as fingerprints.

Fingerprint Factoid:

60% of people have loops, 35% have whorls,

and 5% have arches

There are about 150 individual ridge characteristics on the average full

fingerprint.

ArchesArches 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.

Plain Arch

Ridges enter on one side and

exit on the other side.

Tented Arches

Similar to the plain arch,

but has a spike in the center.

Spike or “tent”

LoopsLoops 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.

Delta

Ulnar Loop (Right

Thumb)

Loop opens toward

right or the ulna bone.

Radial Loop (Right

Thumb)

Loop opens toward the

left or the radial bone.

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.

WhorlsWhorls 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.

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.

Plain

Whorl

Central

Pocket

Whorl

Whorls – Part 2

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.

Double Loop Whorl

Double loop whorls are

made up of any two loops

combined into one print.

Delta

Delta

Identify each fingerprint pattern.

Right Hand

Left Hand

Left Hand

Right Hand

Right Hand

Ridgeology: The study of the uniqueness of friction ridge structures

and their use for personal identification.1

1Introduction to Basic Ridgeology by David Ashbaugh, May 1999 Image from http://www.cs.usyd.edu.au/~irena/minutia.gif

The koala is one of the few mammals (other than primates) that

has fingerprints. In fact, koala fingerprints are remarkably

similar to human fingerprints; even with an electron microscope,

it can be quite difficult to distinguish between the two.

As we have learned in our first lesson, a

fingerprint is made of a series of ridges and

valleys on the surface of the finger. The

uniqueness of a fingerprint can be determined by

the pattern of ridges and valleys as well as the

minutiae points, which are points where the ridge

structure changes.

Fingerprint Identification

When minutiae on two different prints match, these are called

points of similarity or points of identification. At this point there

is no international standard for the number of points of

identification required for a match between two fingerprints.

However, the United Kingdom requires a minimum sixteen points

while Australia requires twelve.

There are about 150 individual ridge characteristics on the

average full fingerprint.

Automated Fingerprint Identification System (AFIS)

http://www.fdle.state.fl.us/CrimeLab/images/fingerrint%20comparison%20for%20afis.jpg

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.

Rid

ge

Ch

ara

cter

isti

cs

Use these characteristics as points of identification when comparing fingerprint

samples. The more points you can find in common, the better the match!

Forensic Science:

Fundamentals &

Investigations, Chapter 6 22

Forensic Science:

Fundamentals &

Investigations, Chapter

6 23

Characteristics of

Fingerprints • Forensic examiners look for

– Core

(the center of a whorl or loop)

– Deltas

(triangular regions near a loop)

• Ridge count

– Counting from the core to the

edge of the delta

– Distinguishes one fingerprint

from another

http://cnx.org/content/m12574/latest/properties.jpg

Ridge Characteristics

Crossover

Core

Bifurcation (fork)

Ridge ending

Island

Delta

Pore

Scar

http://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpg

How many ridge characteristics can you identify in this fingerprint?

• The way a suspect print is analyzed is that it’s compared to a print found at a crime scene. If there are a certain number of points of minutiae that match, then a match is made.

• Minutiae are small details that are breaks in the patterns of the ridges. No two people have the same set of minutiae.

Examples of types of minutiae from

perso.orange.fr/.../types/fingerprint.ht

m

Analyzing Prints

http://perso.orange.fr/fingerchip/biometrics/types/fingerprint.htm

Print Types

• Latent prints- latent prints are hidden and deposited via the secretions from skin. They are often made visible through a number of different techniques.

• Patent prints- highly visible and made from foreign substances such as blood. Since they need no further visualization, they are often just photographed to preserve the evidence.

• Plastic prints- Friction ridge impressions deposited in a material that retains the shape such as clay or melted wax.

PC system (Primary Classification)

The primary classification system is a

system concerning the whorl patterns in

the fingerprints. Everyone is assigned a pc

value according to the whorls on their

fingers. This system is not used for

identification, but for narrowing the pool of

candidates.

Classification Review• Arches

• Whorls

• Loops

The most commonly found types

of fingerprints are whorls, while

the least common types are

arches. Loops fall somewhere in

between.

There is more specific types of classification

techniques, and these are just the most basic three.

For example, arches can be broken down into plain

arches or tented arches, and whorls can be broken

down into accidental whorls, or any other number of

whorl types.

IT IS NECESSARY TO OBTAIN A FULL PRINT

FROM A SUSPECT INORDER TO MATCH

FINGERPRINT FOUND AT A CRIME SCENE.

Fingerprint Forensic FAQs

• Can fingerprints be erased?Only temporarily; they will grow back if removed with chemicals

• Is fingerprint identification reliable?Yes, but analysts can make mistakes

• 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

It’s time to make

some prints!

Avoid

Partial

PrintsGOOD PRINT

Get as much of the top part

of your finger as possible!

Techniques For Lifting a

Print



33

Fingerprint Forensic FAQs

• How are latent fingerprints collected?

Dusting

• Used on smooth, non-porous materials.

• The area is lightly and carefully dusted with either a black or white powder, depending on the contrasting surface.

• The dust is lifted with tape and set against a contrasting background.

• The print is preserved via photography.

Fingerprint dusting in a lab

Iodine Fuming

• Suspect material is

placed in an enclosed

cabinet along with iodine

crystals.

• The crystals are heated,

and will sublimate (turn

into a gas vapor).

• The vapors cause the

prints to visualize.

Fingerprint visualized with

iodine fuming.

Chemical Treatment

• Ninhydrin (triketohydrindene hydrate)-

this chemical is sprayed onto a porous

surface via an aerosol can. Prints

begin to visualize an hour or two after

application, although the process can

be accelerated through heating the

print.

• Silver nitrate- silver nitrate is sprayed

onto the porous surface and left to dry.

Then it is exposed to ultraviolet light to

visualize the prints.Silver Nitrate spray

bottle

Superglue Fuming

• Used mainly on non-porous materials.

• Superglue is placed on cotton and treated with sodium hydroxide.

• Fumes can also be created by heating the glue.

• The fumes and the object are contained in a closed chamber for up to six hours.

• The fumes adhere to the print, visualizing it.

Fuming tank

1 – Blow up your balloon about halfway and twist the end to keep the

air from coming out. Do not tie it off!

2 – Use an ink pad to make a print with all of your fingers and label each

one with a permanent marker. Write your name on the balloon as well.

3 – Blow up the balloon to full size and tie the end.

4 – Analyze the fingerprints to find several ridge structures that we have

discussed. Use a highlighter to mark these structures on your “My

Prints” worksheet.

Try It!

Think About It!

Which ridge structures were most common in your fingerprints?

Which ridge structures were most common in your group?

Were there any structures that were not found in any of the fingerprints?

Balloon Fingerprint Activity: http://www.msichicago.org/fileadmin/Education/learninglabs/lab_downloads/fingerprint_analysis.pdf

Ten Card Example

Directions

1st – Roll the “pad” portion of your thumb over the

ink pad from the left side of your thumb to the

right. You do not have to push down really hard!

2nd – Roll the “pad” portion of your thumb from the left side of

your thumb to the right in the correct box on your paper to make a

thumbprint.

3rd – Continue this process to make a fingerprint of all ten fingers

on the “My Prints” worksheet.

4th –Use your notes and a magnifying lens to help you figure out

what type of pattern is found in each of your fingerprints. Label

each one with the pattern’s name.

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