fingerprints. introduction –most widely used of personal identification techniques –involves the...
TRANSCRIPT
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
22
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.
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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.
PA
LM
PR
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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