Forensic Science: Fundamentals & Investigations, Chapter 6 1 Chapter 6 Fingerprints By the end of this chapter you will be able to: discuss the history.

Forensic Science: Fundamentals & Investigations, Chapter 6 1

Chapter 6 Fingerprints By the end of this chapter you will be able to:

discuss the history of fingerprinting describe the characteristics of fingerprints and

fingerprinting minutiae explain when and how fingerprints are formed describe what causes fingerprints to be left on objects identify the basic types of fingerprints describe how criminals attempt to alter their fingerprints

All Rights Reserved South-Western / Cengage Learning © 2009


Chapter 6 Fingerprints By the end of this chapter you will be able to:

determine the reliability of fingerprints as a means of identification

describe the Integrated Automated Fingerprint Identification System (IFAIS)

explain how fingerprint evidence is collected describe the latest identification technologies determine if a fingerprint matches a fingerprint on

record use the process of lifting a latent print


Historical DevelopmentHistorical Development

1. The oldest known documents showing fingerprints date from third century B.C. China.

2. In ancient Babylon (dating back to 1792-1750 B.C.), fingerprints pressed into clay tablets marked contracts.

3. 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.

4. 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.


Historical Development Historical Development

5. Nine fingerprint patterns were described in 1823 by Jan Evangelist Purkyn.

6. Sir William Herschel (shown at the right), in 1856, began the collection of fingerprints and noted they were not altered by age.

First Fingerprint collection began in 1856

7. Alphonse Bertillon created a way to identify criminals that was used in 1883 to identify a repeat offender.


Case of Will West

A strange occurrence at the Leavenworth Penitentiary that year changed this forever:

A prisoner by the name of Will West was brought to the prison for in processing. Officials were alarmed because a man named William West had been incarcerated there since 1901 and they assumed he had escaped and been returned. A check of the records seemed to confirm this.

The only problem was that William West was still in his cell! The new Mr. West was a different man. But the two resembled each other so closely that the Bertillon system of identification widely used at the time indicated that they were the same person! It was not until the two Wests, who denied any relation, were fingerprinted that this incredible coincidence was fully understood:

6


Historical Development Historical Development

8. 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.

9. 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.

10. 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).

What is the layer of skin that produces fingerprints?

The dermal layer responsible for fingerprints is the papillary layer

LEARN the layers of the integumentary system!!




What Are Fingerprints?

All fingers, toes, feet, and palms are covered in small ridges.

– Plantar, Datyl, Palmar

These ridges are arranged in connected units called dermal, or friction, ridges.

These ridges help us get or keep our grip on objects.

Natural secretions plus dirt on these surfaces leave behind an impression (a print) on those objects with which we come in contact.


Formation of Fingerprints

An animal’s external tissue (skin) consists of (a) an inner dermis and (b) an outer epidermis.

The creation of fingerprints occurs in a special layer (the basal layer) in the epidermis where new skin cells are produced.

Fingerprints probably begin forming at the start of the 10th week of pregnancy.

Because the basal layer grows faster than the others, it collapses, forming intricate shapes.


Characteristics of Fingerprints

There are 3 general fingerprint distinctions:

ARCH WHORL LOOP

About 5% About 30% About 65% of the population

Fingerprint – Super Glue Chamber

Making your own “fume chamber” Bring your own “homemade fume chamber”

or own “homemade” method of fingerprinting to try out in class on Monday Its “DYI Fingerprint lab”….


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 ArchRidges 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”

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 2Accidental 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



Forensic examiners look for the presence of a core (the center of a whorl or loop) and deltas (triangular regions near a loop).

A ridge count is another characteristic that distinguishes one fingerprint from another. The count is made from the center of the core to the edge of the delta.



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%). Even twins have unique fingerprints due to

small differences (called minutiae) in the ridge patterns.

Look for these basic patterns

Other details used for identification

Minutiae

1. Line starts

2. Line stops

3. Line intersections

4. Bifurcations

Pores

1. Frequency

2. Number per line

Minutiae




Board quest….

1. What type of finger print pattern is shown above?

2. What type of finger print pattern is shown above?


Answer!

Plain Arch Double loop



Types of Fingerprints

There are 3 types of prints that investigators look for at crime scenes:

1. Patent fingerprints are visible prints transferred onto smooth surfaces by blood or other liquids.

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.

Finding Fingerprints

http://www.youtube.com/watch?v=mc_l1d--0nQ



Fingerprint Forensic FAQs Can fingerprints be erased?

No, if, for example, they are removed with chemicals, they will grow back.

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

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. However, the matches are probable – NOT like TV CSI


Fingerprint Forensic FAQs

How are latent fingerprints collected?


The Future of Fingerprinting New scanning technologies and digitally

identifying patterns may eliminate analytical mistakes.

Trace elements of objects that have been touched are being studied to help with the identification of individuals.

To help with identification, other physical features such as eyes and facial patterns are also being studied.

Other Prints?

Toes, palms, and even lips have unique prints as well



. . . . . . . . . . . . . . . . . Summary. . . . . . . . . . . . . . . . . Summary

Fingerprints have long been used for identification, and in the mid-1800s were recognized as unique to each person.

Three main groups include arches, whorls, and loops. Basic analysis includes looking for cores, deltas, and

making a ridge count. Investigators search for patent, plastic, and latent prints. Dusting with powders or using special chemicals can make

latent fingerprints visible. New developments may eliminate errors by analysts.

Forensic Science: Fundamentals & Investigations, Chapter 6 1 Chapter 6 Fingerprints By the end of this chapter you will be able to: discuss the history.

Documents

collection of fingerprints

fundamentals investigations

forensic science

fingerprints date

reliability of fingerprints

causes fingerprints

fingerprint patterns

fingerprint collection