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LATENT PRINTS

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Title: LATENT PRINTS


1
FINGERPRINTS
2
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.

3
FINGERPRINTS
  • Objectives
  • Understand the anatomy of skin as it relates to
    fingerprints
  • Fingerprint classification systems
  • Fingerprint characteristics
  • Development of latent prints

4
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).

5
FINGERPRINTS
  • 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

6
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

7
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

8
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

9
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

10
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. 

11
FINGERPRINTS
  • Alphonse Bertillion
  • French Police Officer
  • Devised and introduced the first systematic
    attempt at personal ID based on body types in
    1883

12
FINGERPRINTS
  • In 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.

13
FINGERPRINTS
  • Francis Galton
  • 1892 Book on Fingerprints
  • Naming 3 patterns
  • Loop
  • Arch
  • Whorl
  • Demonstrated that no two are unlike
  • Fingerprints remain unchanged

14
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.

15
FINGERPRINTS
  • 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 Henrys system to file
    fingerprints.

16
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 Worlds Fair, fingerprinting began to be
    used in earnest in all major U.S. cities.

17
FINGERPRINTS
  • Fingerprint Classification
  • 3 basic principles
  • Fingerprints are an individual characteristic
  • They remain unchanged throughout a persons
    lifetime
  • They have general ridge patterns (friction
    ridges) that allow them to be classified and used
    in personal ID

18
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.

19
Classification of Fingerprints
FINGERPRINTS
Arch Loop Whorl
20
FINGERPRINTS
  • Fingerprints are classified in a three-way
    process
  • By the shapes and contours of individual patterns
  • By noting the finger positions of the pattern
    types
  • By relative size, determined by counting the
    ridges in loops and by tracing the ridges in
    whorls

21
FINGERPRINTS
  • Ridge Patterns
  • 3 Basic types
  • Loops 60
  • Whorls 35
  • Arches 5

Population Distribution of Ridge Patterns
22
Fingerprint Patterns
23
FINGERPRINTS
  • In this picture the technician is demonstrating
    the location of ridge endings, bifurcations and
    dots.

24
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.

25
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 individuals lifetime.

26
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
    fingers ridge pattern (a fingerprint).

27
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.

28
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.

29
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.

30
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

31
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

32
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
suspects fingers. Courtesy New Jersey State
Police.
36
Figure 145  Loop pattern.
37
Whorl patterns.
38
Arch patterns.
39
PALM PRINTS
40
LATENT PRINTS
  • 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.

41
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

42
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.

43
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 systems
    file.

44
LATENT PRINTS
  • 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
  • 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.

45
LATENT PRINTS
  • The FBI system
  • radial loop
  • ulnar loop
  • double loop
  • central pocket loop
  • plain arch
  • tented arch
  • plain whorl
  • accidental
  • Primary Classification
  • Can divide all the fingerprints in the world into
    1024 groups
  • Not widely used
  • http//www.nifs.com.au/FactFiles/Fingerprints/how.
    asp?pagehow

46
LATENT PRINTS
  • Major Fingerprint
  • Characteristics
  • Typelines
  • Deltas
  • Cores

47
LATENT PRINTS
  • Surface Print
  • the same fingerprint as it would be detected on
    a surface.

48
LATENT PRINTS
  • Classification of Loops
  • Delta
  • Sufficient recurve
  • Ridge count
  • Radial/ulnar loops
  • Classification of Arches
  • Plain arches
  • Tented arches
  • Angular
  • Up thrust

http//155.217.58.58/cgi-bin/atdl.dll/fm/19-20/ch7
.htms8 http//biometrics.cse.msu.edu/fingerprint.
html Websites show an array of fingerprint
patterns.
49
LATENT PRINTS
  • Fingerprint Impressions
  • Inked Fingerprint Examination Fingerprints from
    the Living!
  • Start with clean hands not just yours!

50
LATENT PRINTS
  • Rolled Impressions
  • Plain Impressions
  • Palm Prints
  • Major Case Prints

51
LATENT PRINTS
  • Obtaining Impressions from Corpses
  • Major Case Prints are always obtained from
    corpses
  • Used to identify or eliminate latent print
    evidence
  • Identification of the deceased

52
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

53
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.

54
LATENT PRINTS
  • Indented Prints - prints that are easily seen
    embedded in some type of soft surface, such as
    putty, plaster, sand or candle wax.

55
LATENT PRINTS
  • Techniques of Print Processing
  • At the Crime Scene
  • examine all surfaces and objects
  • photograph and collect all indented and visible
    prints

56
LATENT PRINTS
  • The 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

57
LATENT PRINTS
  • The amount of time prints remain on an object is
    affected by
  • Weather
  • Air currents
  • Humidity

58
LATENT PRINTS
  • Latent print evidence is divided into two
    categories
  • Porous
  • paper, unfinished wood, cardboard
  • Non-porous
  • plastic, glass, metal, foil

59
LATENT PRINTS
  • Porous evidence - paper, unfinished wood,
    cardboard
  • Usually preserved well because print residue can
    soak into the surface

Iodine Fuming
60
Ninhydrin Physical Developer
61
LATENT PRINTS
  • Non-porous sample
  • Thumbprint found on metal latch

62
LATENT PRINTS
  • Powdering
  • 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).

63
LATENT PRINTS
  • Regular 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.

64
LATENT PRINTS
  • Magnetic Powders
  • Special surfaces i.e.,
  • shiny magazine covers
  • coated surfaces
  • plastic storage or sandwich bags

65
LATENT PRINTS
  • Fluorescent powders
  • Regular or magnetic
  • Observe the development of the latent prints
    with a UV light source while applying the
    powders.

66
LATENT PRINTS
  • Lifting
  • Rubber lifters - lifting prints from curved or
    uneven surfaces
  • Transparent lifting tapes Reversed print

67
LATENT PRINTS
  • Chemical Processing
  • Done at the laboratory
  • Preferred method with porous surfaces

68
LATENT PRINTS
  • Physical Development Technique
  • Small Particle Reagent (SPR)
  • can be used on
  • Paper, cardboard
  • New, rusty, galvanized metal
  • Bricks, rocks, concrete,
  • Plastic, vinyl
  • Wood
  • Glass.

69
Super Glue Fuming
Super glue fuming print
70
LATENT PRINTS
  • Chemical Development Techniques
  • Ninhydrin - porous surfaces (paper, cardboard,
    and wood)
  • Diazafluoren (DFO)- 2.5x more sensitive than
    Ninhydrin alone
  • Sticky Side Powder - adhesive tapes labels
  • Iodine Fuming - paper surfaces, and hard smooth
    surfaces
  • Cyanoacrylate Fuming - super glue

71
LATENT PRINTS
  • Dye Stains
  • Sudan Black- develop latent prints on smooth or
    rough, nonporous surfaces contaminated with
    greasy, oily and sticky substances

72
LATENT PRINTS
  • Other Dyes
  • Ardrox Fluorescent Dye UV lamp
  • TapeGlo Fluorescent Dye
  • Amido Black - sensitive to blood proteins
  • Crystal Violet
  • Physical developer (PD)

73
LATENT PRINTS
  • Mechanical Methods
  • Electrostatic Detection Apparatus (ESDA)
  • X-ray Detection (lead powder)
  • Vacuum Metal Deposition

74
LATENT PRINTS
  • Surface Effects -The use of two or more methods
    in a sequence of processing techniques.
  • Sequencing of Print Development (Smooth)
  • Visual examination using necessary light
  • Examination with specialized light sources (UV)
  • Dust with non-magnetic powder
  • Magnetic powder dusting and or fluorescent powder
  • Fluorescent Dye staining

75
LATENT PRINTS
  • Sequencing of Print Development (Porous surfaces)
  • Visual examination
  • Fluorescent examination
  • Iodine fuming
  • Magnetic powder
  • DFO
  • Ninhydrin
  • PD

76
LATENT PRINTS
  • Latent 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

77
LATENT PRINTS
  • Latent 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

78
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.

79
Automated Fingerprint Identification Systems
  • The introduction of AFIS in 1997 has allowed
    fingerprint techs to scan fingerprint images into
    the database for easy storage, retrieval, and
    comparison.

80
AFIS (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.

81
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.

82
Digital Imaging for Fingerprint Enhancement
  • 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

83
Automated Fingerprint Identification Systems
  • 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.

84
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.

85
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.

86
FingerPrint Humor
John Dillinger tried to burn off his fingerprints
with acid but even this failed to do so!
87
FINGERPRINTS
The End
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