Download Fingerprint PowerPoint - Blair Community Schools

11/16/16
Chapter 6 Fingerprints
By the end of this chapter you will be able to:
x
l  Vocabulary… Fill in from page 133
All rights Reserved
South-Western / Cengage
Learning © 2009
1
Forensic Science: Fundamentals & Investigations, Chapter 1
All Rights Reserved South-Western / Cengage Learning © 2009
2
Forensic Science: Fundamentals & Investigations, Chapter 6
Chapter 6 Fingerprints
Chapter 6 Fingerprints
By the end of this chapter you will be able to:
By the end of this chapter you will be able to:
l  determine the reliability of fingerprints as a means of
l  discuss the history of fingerprinting
identification
l  describe the characteristics of fingerprints and
l  describe the Integrated Automated Fingerprint
fingerprinting minutiae
Identification System (IFAIS)
l  explain when and how fingerprints are formed
l  explain how fingerprint evidence is collected
l  describe the latest identification technologies
l  determine if a fingerprint matches a fingerprint on
l  describe what causes fingerprints to be left on objects
l  identify the basic types of fingerprints
record
l  describe how criminals attempt to alter their fingerprints
l  use the process of lifting a latent print
All Rights Reserved South-Western / Cengage Learning © 2009
3
Forensic Science: Fundamentals & Investigations, Chapter 6
4
Unaltered Identity
Forensic Science: Fundamentals & Investigations, Chapter 6
Historical Development
l  Groups of 3 / Read p. 132
l 
The oldest known documents showing fingerprints date
from third century B.C. China.
l 
In ancient Babylon (dating back to 1792-1750 B.C.),
fingerprints pressed into clay tablets marked contracts.
l 
The earliest written study (1684) is Dr. Nehemiah’s paper
describing the patterns he saw on human hands under a
microscope, including the presence of ridges.
l 
In 1788, Johann Mayer noted that the arrangement of
skin ridges is never duplicated in two persons. He was
probably the first scientist to recognize this fact.
l  Piece of Paper / Everyone’s Name / To Hand In
1.  What movies have you seen that depicted
5
criminals and the crimes they committed?
2.  Were these criminals caught in the movies?
3.  What evidence did the police have that was
key to putting the criminals behind bars?
4.  In the movies how do criminals try to hide
their fingerprints?
Forensic Science: Fundamentals & Investigations, Chapter 6
6
Forensic Science: Fundamentals & Investigations, Chapter 6
1
11/16/16
Historical Development
l 
Nine fingerprint patterns were described in
1823 by Jan Evangelist Purkyn.
l 
Sir William Herschel (shown at the right), in
1856, began the collection of fingerprints and
noted they were not altered by age.
l 
Alphonse Bertillon created a way to identify
criminals that was used in 1883 to identify a
repeat offender.
In 1888, Sir Francis Galton (shown at the
right), and Sir Edmund Richard Henry,
developed the fingerprint classification system
that is still in use in the United States.
l 
7
Forensic Science: Fundamentals & Investigations, Chapter 6
Historical Development
8
l 
Beginning in 1896, Sir Henry (mentioned in the last entry
on the previous slide), with the help of two colleagues,
created a system that divided fingerprints into groups.
Along with notations about individual characteristics, all
ten fingerprints were imprinted on a card (called a ten
card).
Forensic Science: Fundamentals & Investigations, Chapter 6
What Are Fingerprints?
l  All fingers, toes, feet, and palms are
l  These ridges help us get or keep our grip
on objects.
l  These ridges are arranged in connected
l  Natural secretions plus dirt on these
units called dermal, or friction, ridges.
11
In 1891, Iván (Juan) Vucetich improved fingerprint
collection. He began to note measurements on
identification cards, as well as adding all ten fingerprint
impressions. He also invented a better way of collecting
the impressions.
What Are Fingerprints?
covered in small ridges.
9
l 
Forensic Science: Fundamentals & Investigations, Chapter 6
surfaces leave behind an impression (a
print) on those objects with which we
come in contact.
10
Forensic Science: Fundamentals & Investigations, Chapter 6
Formation of Fingerprints
Formation of Fingerprints
l  An animal’s external tissue (skin) consists
l  Fingerprints probably begin forming at the
of (a) an inner dermis and (b) an outer
epidermis.
l  The creation of fingerprints occurs in a
special layer (the basal layer) in the
epidermis where new skin cells are
produced.
start of the 10th week of pregnancy.
l  Because the basal layer grows faster than
the others, it collapses, forming intricate
shapes.
Forensic Science: Fundamentals & Investigations, Chapter 6
12
Forensic Science: Fundamentals & Investigations, Chapter 6
2
11/16/16
Characteristics of Fingerprints
Characteristics of Fingerprints
l  There are 3 general fingerprint distinctions:
l  Forensic examiners look for the presence of
ARCH
About 5%
of the population
13
WHORL
LOOP
About 30%
of the population
About 65%
of the population
Forensic Science: Fundamentals & Investigations, Chapter 6
a core (the center of a whorl or loop) and
deltas (triangular regions near a loop).
14
Characteristics of Fingerprints
Characteristics of Fingerprints
l  A ridge count is another characteristic that
l Basic patterns can be further divided:
–  Arch patterns can be plain (4%) or
tented (1%).
–  Whorl patterns can be central pocket
(2%), double loop (4%), or accidental
(0.01%).
distinguishes one fingerprint from another.
The count is made from the center of the
core to the edge of the delta.
15
Forensic Science: Fundamentals & Investigations, Chapter 6
16
Forensic Science: Fundamentals & Investigations, Chapter 6
Characteristics of Fingerprints
Types of Fingerprints
l Even twins have unique fingerprints
There are 3 types of prints that investigators
look for at crime scenes:
due to small differences (called
minutiae) in the ridge patterns.
17
Forensic Science: Fundamentals & Investigations, Chapter 6
Forensic Science: Fundamentals & Investigations, Chapter 6
1.  Patent fingerprints are visible prints
transferred onto smooth surfaces by
blood or other liquids.
18
Forensic Science: Fundamentals & Investigations, Chapter 6
3
11/16/16
19
Types of Fingerprints
Types of Fingerprints
2. Plastic fingerprints are indentations
left in soft materials such as clay or wax.
3. Latent fingerprints are not visible but
made so by dusting with powders or the
use of chemicals.
Forensic Science: Fundamentals & Investigations, Chapter 6
20
Ridge Characteristics
l 
§ 
§ 
§ 
§ 
§ 
§ 
§ 
§ 
§ 
§ 
21
Comparison
Minutiae—characteristics of ridge patterns
Ridge ending
Short ridge
Dot or fragment
Bifurcation
Double bifurcation
Trifurcation
Bridge
Island
Enclosure
Spur
Forensic Science: Fundamentals & Investigations, Chapter 6
There are no legal
requirements in the
United States on the
number of points.
Generally, criminal
courts will accept 8 to
12 points of similarity.
22
Forensic Science: Fundamentals & Investigations, Chapter 6
Fingerprint Forensic FAQs
Fingerprint Forensic FAQs
l  Can fingerprints be erased?
l  Is fingerprint identification reliable?
No, if, for example, they are removed
with chemicals, they will grow back.
23
Forensic Science: Fundamentals & Investigations, Chapter 6
Forensic Science: Fundamentals & Investigations, Chapter 6
Yes, but analysts can make mistakes.
24
Forensic Science: Fundamentals & Investigations, Chapter 6
4
11/16/16
Fingerprint Forensic FAQs
AFIS
l  Is fingerprint matching carried out by
§ 
computers in a matter of seconds?
No, but the FBI’s Integrated Automated
Fingerprint Identification System (IAFIS
or AFIS) can provide a match in 2
hours for the prints in its Master File.
25
Forensic Science: Fundamentals & Investigations, Chapter 6
§ 
§ 
§ 
26
§ 
27
Search large files for a set of prints taken
from an individual
Compare a single print, usually a latent print
developed from a crime scene
Forensic Science: Fundamentals & Investigations, Chapter 6
How are latent fingerprints collected?
AFIS
§ 
The Automated Fingerprint Identification
System - a computer system for storing
and retrieving fingerprints
Began in the early 1970’s to:
By the 1990’s most large jurisdictions
had their own system in place. The
problem - a person’s fingerprints may
be in one AFIS but not in others
IAFIS—the FBI’s Integrated Automated
Fingerprint Identification system which
is a national database of all 10-print
cards from all over the country
Forensic Science: Fundamentals & Investigations, Chapter 6
28
Forensic Science: Fundamentals & Investigations, Chapter 6
The Future of Fingerprinting
l  New scanning technologies and digitally
identifying patterns may eliminate
analytical mistakes.
l  Trace elements of objects that have been
touched are being studied to help with the
identification of individuals.
l  To help with identification, other physical
features such as eyes and facial patterns
are also being studied.
29
Forensic Science: Fundamentals & Investigations, Chapter 6
5