FINGERPRINTS

FINGERPRINTS• Introduction

– Most widely used of personal identification techniques

– Involves the study and classification of fingerprints

– The development of latent prints – Comparison of known and unknown

fingerprints.

FINGERPRINTS• Objectives

– Understand the anatomy of skin as it relates to fingerprints

– Fingerprint classification systems– Fingerprint characteristics – Development of latent prints

FINGERPRINTS• The Anatomy of Skin

• 3 layers– The Epidermis– The Dermis– The Hypodermis

• Each ridge of the epidermis (outer skin) is dotted with sweat pores and is anchored to the dermis (inner skin).

• RIDGE arrangement on every finger of every human being is unique

• Fingerprints serve to reveal an individual's true identity despite personal denial, assumed names, or changes in personal appearance resulting from age, disease, plastic surgery, or accident

FINGERPRINTS

FINGERPRINTS• The Anatomy of Skin

• 3 layers– The Epidermis: varies in thickness

depending on the body area and contains no blood vessels

– The Dermis: a thick layer of connective tissue that contains blood vessels and provides nutrients and blood to the epidermis

FINGERPRINTS• The Anatomy of Skin

The skins appendages or accessory structures are embedded in the epidermis and dermis. The accessory structures include:

– Hair follicles – Sweat glands – Sebaceous glands – Nails

FINGERPRINTS• The Anatomy of Skin

– The Hypodermis: the subcutaneous tissue that lies below the dermis, and consists of connective tissue, fat cells, macrophages, fibroblasts, blood vessels, nerves and the base of the accessory glands

FINGERPRINTS• Functions of the Skin

– Provides the first line of defense against invasion by microorganisms and foreign materials

– Inhibits excessive fluid loss – Important in controlling body temperature– Sensory functions

FINGERPRINTS• How Made

– Formed from the RIDGES and GROOVES on the tips of fingers, toes, and palms, which are generated from the DERMAL LAYER of the skin PRIOR TO BIRTH and are totally unique to that person. 

FINGERPRINTSAlphonse BertillionAlphonse Bertillion

French Police OfficerFrench Police Officer

Devised and Devised and introduced the first introduced the first systematic attempt systematic attempt at personal ID at personal ID based on body based on body types in 1883types in 1883

FINGERPRINTSIn 1880, Dr. Henry Faulds

began a study of “skin-furrows” after noticing the finger marks on certain pieces of artifacts.

Suggested that skin ridge pattern could be important for the ID of criminals.

FINGERPRINTSFrancis Galton • 1892 Book on

Fingerprints• Naming 3 patterns

– Loop– Arch– Whorl

• Demonstrated that no two are unlike

• Fingerprints remain unchanged

FINGERPRINTS 1893 - Dr. Juan

Vucetich - Argentine police officer

His classification system has been refined over the years and is still widely used today in most Spanish-speaking countries.

1897, Sir Edward Richard Henry

The fingerprinting bureau - founded at Scotland Yard in 1901

Today, most English-speaking countries, including the US, use a version of Henry’s system to file fingerprints.

FINGERPRINTS

• In 1903, when the Bertillion system could not distinguish between two men (one Will West and the other William West), it was fingerprinting that clearly distinguished them.• After the Will West incident, the use of fingerprinting by the New York City Civil Service Commission in 1901, and the training of American police by Scotland Yard representatives at the 1904 World’s Fair, fingerprinting began to be used in earnest in all major U.S. cities.

FINGERPRINTS

FINGERPRINTSFingerprint Classification

3 basic principles:1. Fingerprints are an individual

characteristic

2. They remain unchanged throughout a person’s lifetime

3. They have general ridge patterns (friction ridges) that allow them to be classified and used in personal ID

LATENT PRINTS• An important part of

a forensic investigation is the identification of the victim or suspect. One of the most useful identification tools is the fingerprint pattern.

Classification of Fingerprints

FINGERPRINTS

Arch Loop Whorl

FINGERPRINTSFingerprints are classified in a three-way

process: 1. By the shapes and contours of individual

patterns

2. By noting the finger positions of the pattern types

3. By relative size, determined by counting the ridges in loops and by tracing the ridges in whorls

FINGERPRINTSRidge Patterns

• 3 Basic types1. Loops – 60%

2. Whorls – 35%

3. Arches – 5%

Loops

Whorls

Arches

Population Distribution of Ridge Patterns

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Fingerprint Patterns

In this picture the technician is demonstrating the location of ridge endings, bifurcations and dots.

FINGERPRINTS

PRINCIPAL ONE

• After a three year study, it was determined that “no valid basis exists for requiring a predetermined minimum number of friction ridge characters which must be present in two impressions in order to establish positive identification.”

• In a judicial proceeding, an expert must demonstrate a point-by-point comparison in order to prove the identity of an individual.

PRINCIPAL TWO• The dermal papillae is the layer of cells between

the epidermis and dermis, that is responsible for determining the form and pattern of the ridges on the surface of the skin.

• Once the dermal papillae develop in the human fetus, the ridge patterns will remain unchanged throughout life except to enlarge during growth. Thus, a fingerprint will remain unchanged during an individual’s lifetime.

PRINCIPAL TWO

• Each skin ridge is populated with pores leading to sweat glands from which perspiration is deposited on the skin.

• Once the finger touches a surface, perspiration, along with oils that may have been picked up by touching the hairy portions of the body, is transferred onto that surface, leaving the finger’s ridge pattern (a fingerprint).

PRINCIPAL THREE• All fingerprints are divided into three classes on the

basis of their general pattern: loops, arches, and whorls (L.A.W.).

• A loop must have one or more ridges entering from one side of the print, recurving, and exiting from the same side.– If the loop opens toward the little finger, it is called an

ulnar loop.– If the loop opens toward the thumb, it is called a radial

loop. • All loops must have one delta, which is the ridge point at

or directly in front of the point where two ridge lines (type lines) diverge.

PRINCIPAL THREE

• Whorls are divided into four groups: plain, central pocket loop, double loop, and accidental.

• All whorl patterns have type lines and a minimum of two deltas.

• A plain whorl and a central pocket loop have at least one ridge that makes a complete circuit.

• The double loop is made up of two loops combined into one fingerprint.

• An accidental either contains two or more patterns, or is a pattern not covered by the other categories.

PRINCIPAL THREE

• Arches, the least common of the three general patterns, are divided into two distinct groups: plain arches and tented arches.

• The plain arch is formed by ridges entering from one side of the print, rising and falling, and exiting on the opposite side (like a wave).

• The tented arch is similar to the plain arch except that instead of rising smoothly at the center, there is a sharp upthrust or spike, or the ridges meet at an angle that is less than 90 degrees.

• Arches do not have type lines, deltas, or cores.

THE LOOP

• The LOOP is a classification of fingerprints characterized by ridge lines that enter from one side of the pattern and curve around to exit from the same side if the pattern.

• A loop MUST have:– One of more ridges entering from one side

of the print and re-curve and then exit from the same side.

-Ulnar Loop -Radial Loop

-Delta -Core

THE WHORL

• The WHORL is a class that includes ridge patterns that are generally rounded or circular in shape and have two deltas.

• Divided into 4 groups– Plain Whorls– Central Pocket Loop– Double Loop– Accidental

THE ARCH

• The ARCH is a classification of fingerprints characterized by ridge lines that enter the print from one side and flow to the other side.

• Two types:– Plain– Tented

• Arches do not have type

lines, deltas, or cores.

33

Fingerprint Ridge Characteristics

34

Fingerprint ridge characteristics. Courtesy Sirchie Finger Print Laboratories, Inc., Youngsville, N.C., www.sirchie.com.

35

A fingerprint exhibit illustrating the matching ridge characteristics between the crime-scene print and an inked impression of one of the

suspect’s fingers. Courtesy New Jersey State Police.

36

Figure 14–5  Loop pattern.

37

Whorl patterns.

38

Arch patterns.

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HENRY SYSTEM -

Converted ridge patterns into letters and numbers in the form of a fraction – Too cumbersome for large # of

patterns– Due to this, and the need to file

millions of fingerprint cards at the FBI, a modified Henry System was implemented.

LATENT PRINTS

LATENT PRINTS• The FBI system

– A system based on an applied classification formula

– Based on a series of modifications and extensions of the Henry System

PRIMARY CLASSIFICATION• Fingerprint classification systems are based on

knowledge of fingerprint pattern classes.• First, fingers are paired up, placing one finger in the

numerator of a fraction and the other in the denominator.• The presence or absence of the whorl pattern is the

basis for the determination of the primary classification.

• If a whorl pattern is found on any finger of the first pair, it is assigned a value of 16; on the second pair, an 8; on the third pair, a 4; on the second pair, a 2; and on the last pair, a 1.

• Any finger having a loop or arch is assigned a 0.

PRIMARY CLASSIFICATION

• After values for all 10 fingers are obtained, they are totaled, and a 1 is added to both the numerator and denominator.

• The fraction thus obtained is the primary classification.• Approximately 25 % of the population falls into the 1/1

category; that is, all their fingers have either loops or arches.• A fingerprint classification system cannot in itself

unequivocally identify an individual; it will merely provide the fingerprint examiner with a number of candidates, all of whom have an indistinguishable set of prints in the system’s file.

• Primary Classification - the first classification method that allowed all fingerprint cards to be divided into 1024 groups. It was based on the presence or absence of a whorl pattern.

R. Index (16)R. Thumb

R. Ring (8) R. Middle

L. Thumb (4) R. Little

L. Middle (2) L. Index

L. Little (1) L. Ring

LATENT PRINTS

LATENT PRINTSThe FBI system 1. radial loop 2. ulnar loop 3. double loop 4. central pocket loop 5. plain arch 6. tented arch 7. plain whorl 8. accidental

Primary Classification • Can divide all the

fingerprints in the world into 1024 groups

• Not widely used• http://www.nifs.com.au/Fa

ctFiles/Fingerprints/how.asp?page=how

Major Fingerprint

Characteristics• Typelines

• Deltas

• Cores

LATENT PRINTS

Surface Print:

the same fingerprint as it would be detected on a surface.

LATENT PRINTS

LATENT PRINTSClassification of

Loops:

1. Delta

2. Sufficient recurve

3. Ridge count

4. Radial/ulnar loops

Classification of Arches:

1. Plain arches

2. Tented arches

3. Angular

4. Up thrust

http://155.217.58.58/cgi-bin/atdl.dll/fm/19-20/ch7.htm#s8

http://biometrics.cse.msu.edu/fingerprint.html

Websites show an array of fingerprint patterns.

LATENT PRINTSFingerprint Impressions:Inked Fingerprint Examination

– Fingerprints from the Living!

Start with clean hands – not just yours!

LATENT PRINTS• Rolled Impressions

• Plain Impressions • Palm Prints

• Major Case Prints

LATENT PRINTSObtaining Impressions from Corpses

Major Case Prints are always obtained from corpses

• Used to identify or eliminate latent print evidence

• Identification of the deceased

LATENT PRINTS“Dusting For Prints”Latent Fingerprint

Development

Means to develop latent prints include:

Processing evidence and other surfaces using powders, chemicals and specialized lighting techniques

LATENT PRINTS• Friction Ridges • Latent Prints- Some

impressions are easily seen (called patent prints) and others can only be seen with specialized techniques and are called latent prints.

LATENT PRINTS

Indented Prints - prints that are easily seen embedded in some type of soft surface, such as putty, plaster, sand or candle wax.

LATENT PRINTSTechniques of Print

Processing

• At the Crime Scene– examine all surfaces

and objects – photograph and

collect all indented and visible prints

LATENT PRINTSThe visibility of latent prints depends on

numerous factors: • The physical condition of the person who left

the print • The surface of the object • Lighting angles • The time since the prints were placed • Amount of heat to which they have been

exposed

LATENT PRINTS

The amount of time prints remain on an object is affected by: – Weather – Air currents – Humidity

LATENT PRINTSLatent print evidence is divided into two

categories:

– Porous • paper, unfinished wood, cardboard

– Non-porous• plastic, glass, metal, foil

• Porous evidence - paper, unfinished wood, cardboard– Usually preserved well because print

residue can soak into the surface

LATENT PRINTS

Iodine Fuming

Ninhydrin&

Physical Developer

• Non-porous sample

• Thumbprint found on

metal latch

LATENT PRINTS

LATENT PRINTSPowdering• Use the powder that provides the best

contrast with the background for photography purposes, but black and white are typically used

• Applied with brushes and other application instruments (magnetic wands, cotton fabric).

LATENT PRINTSRegular Powders

Most commonly used for processing prints on windows, counter-tops, television sets, metal file cabinets, painted doors, mirrors, broken glass and metal window frames.

LATENT PRINTSMagnetic Powders

• Special surfaces i.e.,– shiny magazine covers– coated surfaces– plastic storage or sandwich bags

LATENT PRINTSFluorescent powders

Regular or magnetic

Observe the development of the latent prints with a UV lightUV light source while applying the powders.

LATENT PRINTSLifting

Rubber lifters - lifting prints from curved or uneven surfaces

Transparent lifting tapes – Reversed print

LATENT PRINTSChemical Processing

• Done at the laboratory• Preferred method with porous surfaces

LATENT PRINTSPhysical Development Technique• Small Particle Reagent (SPR)

– can be used on:

Paper, cardboard

New, rusty, & galvanized metal

Bricks, rocks, concrete,

Plastic, vinyl

Wood

Glass.

Super Glue Fuming

Super glue fuming print

LATENT PRINTSChemical Development Techniques

1. Ninhydrin - porous surfaces (paper, cardboard, and wood)

2. Diazafluoren (DFO)- 2.5x more sensitive than Ninhydrin alone

3. Sticky Side Powder - adhesive tapes & labels

4. Iodine Fuming - paper surfaces, and hard smooth surfaces

5. Cyanoacrylate Fuming - super glue

LATENT PRINTSDye Stains• Sudan Black- develop

latent prints on smooth or rough, nonporous surfaces contaminated with greasy, oily and sticky substances

LATENT PRINTS• Other Dyes

– Ardrox Fluorescent Dye – UV lamp– TapeGlo Fluorescent Dye – Amido Black - sensitive to blood proteins – Crystal Violet – Physical developer (PD)

LATENT PRINTSMechanical Methods• Electrostatic Detection Apparatus (ESDA)• X-ray Detection (lead powder)• Vacuum Metal Deposition

LATENT PRINTSSurface Effects -The use of two or more

methods in a sequence of processing techniques. – Sequencing of Print Development (Smooth)1. Visual examination using necessary light

2. Examination with specialized light sources (UV)

3. Dust with non-magnetic powder

4. Magnetic powder dusting and or fluorescent powder

5. Fluorescent Dye staining

LATENT PRINTS• Sequencing of Print Development

(Porous surfaces)

1. Visual examination

2. Fluorescent examination

3. Iodine fuming

4. Magnetic powder

5. DFO

6. Ninhydrin

7. PD

LATENT PRINTSLatent Prints on Skin - can be washed away

with water excreted through perspiration. With homicide victims, the skin has often been exposed to harsh conditions, such as mutilation, contamination with body fluids, weather effects, and decomposition

LATENT PRINTSLatent Prints in Blood -

Leuchomalachite Green - used to stain fingerprints in blood that can be photographed

Amido Black - traditional treatment for blood prints.

*Chemical processing should only be carried on blood if visual techniques fail

AFIS (Automated Fingerprint Identification Systems)

The Integrated Automated Fingerprint Identification System, (AFIS)

National fingerprint and criminal history system maintained by the Federal Bureau of Investigation (FBI), Criminal Justice Information Services (CJIS) Division.

• The introduction of AFIS in 1997 has allowed fingerprint techs to scan fingerprint images into the database for easy storage, retrieval, and comparison.

Automated Fingerprint Identification Systems

•The AFIS provides automated fingerprint search capabilities, latent searching capability, electronic image storage, and electronic exchange of fingerprints and responses, 24 hours a day, 365 days a year.

•As a result of submitting fingerprints electronically, agencies receive electronic responses to criminal ten-print fingerprint submissions within two hours and within 24 hours for civil fingerprint submissions.

AFIS (Automated Fingerprint Identification Systems)

LiveScan Fingerprinting

LiveScan is inkless electronic fingerprinting. The fingerprints are electronically transmitted to the Department of Justice (DOJ) for completion of a criminal record check.

Automated Fingerprint Identification Systems

• Technology can enhance the condition of the prints, which are lifted from the crime scene

• The advancements in computers has greatly improved the fingerprint identification process

• Software has been developed which can now accurately analyze the print and eliminate unwanted background materials, which can impede the latent images

Digital Imaging for Fingerprint Enhancement

• A trained technician scans your fingerprints using an Identix TouchPrint 600™ LiveScan. The electronic fingerprinting appointment takes five to ten minutes and your prints are immediately

available for electronic transmission to the appropriate FBI-Certified channeling agencies for background processing.

Automated Fingerprint Identification Systems

• AFIS has changed the way criminal investigators operate, allowing them to spend less time developing suspect list and more time investigating the suspects generated by the computer.

• The AFIS makes no final decisions on the identity of a fingerprint, leaving this function to the eyes of a trained examiner.

Automated Fingerprint Identification Systems

What are the benefits of LiveScan?

• Live Scan will avoid many of the problems associated with ink prints, such as smudging, smearing, and over or under inking.

• A major benefit of Live Scan is in processing speed since nearly all of those without criminal records are done within 72 hours and up to 30 days if there is a criminal record.

• Rolled ink prints (traditionally submitted on a fingerprint card) can take 10 to 12 days to process (plus mail time) and up to 60 days if there is a criminal record.

Automated Fingerprint Identification Systems

John Dillinger tried to burn off his fingerprints with acid but even this failed to do so!

FINGERPRINTS

The EndThe End