Fingerprint Analysis

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Fingerprint Analysis

• Detecting,
• Identifying, and
• Evaluating Patent Latent Prints

2
History of Fingerprinting

• In earlier civilizations, branding and even
  maiming were used to mark the criminal for what
  he was.
• The thief was deprived of the hand which
  committed the thievery.
• The Romans employed the tattoo needle to identify
  and prevent desertion of mercenary soldiers.

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History of Fingerprints

• Around 1870 a French anthropologist devised a
  system to measure and record the dimensions of
  certain bony parts of the body.
• This Bertillon System, named after its inventor,
  Alphonse Bertillon, was generally accepted for
  thirty years.
• At that time there were two men who were confused
  for being the same person based on the Bertillon
  system.
• Their names were Will and William West
  respectively. Their Bertillon measurements were
  too close/similar.
• However, a fingerprint comparison quickly and
  correctly identified them as two different
  people.
• The West men were apparently identical twin
  brothers per indications in later discovered
  prison records citing correspondence from the
  same immediate family relatives.

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History of Fingerprints

• 1901 Introduction of fingerprints for criminal
  identification in England and Wales, using
  Galton's observations and revised by Sir Edward
  Richard Henry. Thus began the Henry
  Classification System, used even today in all
  English speaking countries.
• 1902 First systematic use of fingerprints in the
  U.S. by the New York Civil Service Commission for
  testing. Dr. Henry P. DeForrest pioneers U.S.
  fingerprinting. 
• 1903 The New York State Prison system began the
  first systematic use of fingerprints in U.S. for
  criminals. 
• 1904 The use of fingerprints began in Leavenworth
  Federal Penitentiary in Kansas, and the St. Louis
  Police Department. They were assisted by a
  Sergeant from Scotland Yard who had been on duty
  at the St. Louis Exposition guarding the British
  Display. 
• 1905 The use of fingerprints began for the U.S.
  Army. Two years later the U.S. Navy started, and
  was joined the next year by the Marine Corp.
  During the next 25 years more and more law
  enforcement agencies join in the use of
  fingerprints as a means of personal
  identification.

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History of Fingerprints

• 1924 An act of congress established the
  Identification Division of the F.B.I.. The
  National Bureau and Leavenworth consolidated to
  form the nucleus of the F.B.I. fingerprint files.
  
• 1946 The F.B.I. had processed 100 million
  fingerprint cards in manually maintained files
  and by 1971, 200 million cards.
• With the introduction of AFIS technology, the
  files were split into computerized criminal files
  and manually maintained civil files. 
• Many of the manual files were duplicates though,
  the records actually represented somewhere in the
  neighborhood of 25 to 30 million criminals, and
  an unknown number of individuals in the civil
  files.

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• Basic Traits of Fingerprints

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Fingerprint Basics

• Fingerprints are formed when a person is
  developing in his/her mothers womb.
• They are friction ridges whose functions are to
  cause friction against objects in order to
  provide a firm grip
• Skin is completely replaced every 30 days, yet
  the folds that make up the fingerprint remain the
  same.

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Fingerprint Basics

• Fingerprints are found on all people and some
  animals.
• They are unique to the individual and remain
  unchanged over a lifetime.
• The pattern of ridges on the friction skin of the
  fingers, palms, toes, sole of the foot are formed
  in utero by about 5 months.
• Even identical twins have different fingerprints.
• Fingerprint configurations are probably
  determined by multiple genes.

• On the top of the ridges are pores that allow
  sweat and or oil to exit from glands.
• Fingerprints are left by the transfer of oil or
  amino acids to a surface, substances on the
  fingers like paint or blood, or by leaving a
  print in a soft substrate.
• Prints that can't be readily seen on a surface
  are called latent and must be visualized by
  various methods.

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Characteristics of Fingerprints

• Johannes Purkinjie described nine different
  patterns or fingerprint classes. These are
  recognized today as four main types whose
  distribution varies with race and different
  fingers. These four main types are arch, tented
  arch, whorl, and loops.
• Arch patterns are rare and the most common
  are loops.
• Arch ridges enter from one side, rise to a ridge
  in the center and exit out the opposite side.
• Tented Arch at least one arch rises to 45 degree
  angle or more.
• Whorl At least one ridge makes a 360 degree
  circle in the center of the print.
• Loop One or more ridges make a loop and then
  exit the same side they entered.
• Within these patterns are what we call minutia
  points.  There are about thirty different types
  of minutae points, and no two people have the
  same types of minutae in the same number in the
  same places on their fingertips.  This is why our
  fingerprints are totally unique.  

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Characteristic of Fingerprints
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Evaluating the Pattern

• A fingerprint is made of a series of ridges and
  furrows on the surface of the finger.
• The uniqueness of a fingerprint can be
  determined by the pattern of ridges and furrows
  as well as the minutiae points.
• Minutiae points are local ridge characteristics
  that occur at either a ridge bifurcation (split
  into two) or a ridge ending.

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Minutia Fingerprint Patterns
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Identifying Prints

• Because of the biological principles, uniqueness
  and permanence, this makes them an ideal tool for
  the identification of persons by means of their
  fingerprints.
• The identification of individuals involves the
  comparison of one fingerprint, from an unknown
  source and comparing it to a fingerprint from a
  known source.
• The characteristics are compared until a
  sufficient number are in agreement for the
  analyst to be satisfied that they are from the
  same source.
• Classifying the general pattern of fingerprints
  allows them to be stored in a filing system and
  subsequently retrieved for comparison.
• Modern technology has allowed this process to
  transferred to computers with the advent of
  automated fingerprint identification systems
  (AFIS).

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Comparing Fingerprint Pattern
Fingerprint matching techniques can be placed
into two categories minutae-based and
correlation based. Minutiae-based techniques
first find minutiae points and then map their
relative placement on the finger. However, there
are some difficulties when using this approach.
It is difficult to extract the minutiae points
accurately when the fingerprint is of low
quality. Also this method does not take into
account the global pattern of ridges and furrows.
The correlation-based method is able to overcome
some of the difficulties of the minutiae-based
approach. However, it has some of its own
shortcomings. Correlation-based techniques
require the precise location of a registration
point and are affected by image translation and
rotation.
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III Identify Specific Patterns on 2nd Print
II Identify Specific Patterns on 1st print
I Mark Print
IV Run a Comparison
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Gaining Skills in Print Comparision

• The comparison of fingerprints, especially latent
  fingerprints (palm prints, footprints), can be
  the single most difficult task in all the
  fingerprint science.
• No matter how skillful an individual may be in
  all the related areas, it is the additional
  ability to accurately compare latent prints
  against known prints that allows the examiner to
  be called a fingerprint expert.
• This ability is gained through training,
  knowledge, experience and work under the guidance
  of a qualified fingerprint expert(s).
• Fingerprint comparison is a skill that can be
  acquired by almost anyone who expends the
  required effort, which can be very demanding.
• It is difficult, but it's not rocket science. If
  you are just beginning, don't get discouraged you
  can do it!

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Latent Prints

• Latent prints are those that cannot be seen by
  the naked eye. They are caused by the
  perspiration and other materials that may be on
  the ridges of the skin.
• The method used for obtaining latent prints
  depends on the type of surface to be examined,
  the manner in which the prints were left, and the
  quantity of material taken to the crime lab.
• They are compared to the prints of all persons
  known to have been at the scene of the crime or
  who had legal access to the crime scene. This
  procedure eliminates all but the criminal's
  prints.
• Making such prints visible is a matter of both
  skill and luck. The following steps provide
  instructions on how to take latent fingerprints.

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How to Dust for Prints

• 1. Dust the surface with the appropriate powder
  and lightly dust the area containing the print.
  (You can choose the appropriate powder by using a
  powder that will contrast with the surface of the
  print.)2. After the print is developed, remove
  the excess powder by gently blowing or brushing
  it away. Be careful not to destroy the print with
  too hard a brush stroke. The "trick" is to use a
  small amount of powder, gentle strokes, and brush
  along the direction of the ridges. You might want
  to use oblique lighting to help visualize the
  print before you begin. 3. Use caution to clear
  away the excess powder around the print before
  you lift it. 

• 4. To lift the print from the dusted item to the
  index card, obtain a 3"-4" length of and place
  one end of tape to the right of the print and
  allow the tape to cover the whole print. Be sure
  that the tape is flat and has no air bubbles. 5.
  Slide a finger over the tape and smooth it down
  over the print to force out all air bubbles. 6.
  The print can be removed pulling up on one end of
  the tape and then placing it on the fingerprint
  card in the same manner as the tape was placed
  over the latent print. 

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Techniques for Developing Latent Prints

• 4. Physical developer - a silver nitrate-based
  liquid reagent.  A dark image is produced when
  the silver nitrate solution reacts with salts in
  the latent print, in the presence of light.
• 5. Super Glue Fuming - a technique for
  visualizing latent fingerprints on non-porous
  surfaces by exposing them to cyanoacrylate
  vapors named for the commercial product, super
  glue.
• 6. Fluorescent Reagents - the chemical DFO
  visualizes latent prints on porous materials when
  exposed to an alternate light source (Saferstein
  408-409).

• 1. Powder Dusting - a powder of contrasting
  color to the surface being dusted is chosen. 
  Impressions on objects such as metal, plastic,
  glass, tile and other non-porous surfaces are
  easily processed with various fingerprint
  powders.
• 2. Iodine Fuming - vapor from warmed iodine
  crystals dissolves in the skin oils in a latent
  print, yielding a yellow brown print.  The
  developed latent prints are photographed
  immediately because they fade rapidly (Lee 140).
  
• 3. Nynhydrin - a chemical reagent used to
  develop latent fingerprints on porous materials
  by reacting with amino acids in perspiration.

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Inking A Person for Prints

• The steps for inking fingers and the steps for
  making impressions on the card are the same.
• Each finger is rolled through the ink on the
  glass and then that finger impression is rolled
  on the fingerprint card.
• All rolling should be made in single movements.
  Do not roll back and forth.
• The pressure should be just enough to apply an
  even coat of ink on the finger and a clear image
  on the card.
• After the procedure is complete, fill in the data
  on the fingerprint card. Sign the card or paper
  for identification. This signature is important
  in legal proceedings.

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Fingerprint Record
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Reasons to Use Fingerprints

• Fingerprinting analysis has been used for more
  than a century, yet it is still widely used in
  law enforcement agencies. 
• Because of its unique characteristic, it is
  conclusive evidence and a valuable tool among
  advanced technology even today. 
• However, there is a chance it might lose its
  ground by DNA fingerprint which is more
  sophisticated and accurate than traditional
  fingerprint.

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WHY USE FINGERPRINTS IN A CRIMINAL INVESTIGATION?

• According to most professional criminal
  investigators, fingerprints obey three
  fundamental principles. These principles are
• A fingerprint is an individual characteristic. It
  is yet to be found that prints taken from
  different individuals possess identical ridge
  characteristics.
• A fingerprint will remain unchanged during an
  individuals lifetime.
• Fingerprints have general characteristic ridge
  patterns that permit them to be systematically
  classified.

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WHY USE FINGERPRINTS IN A CRIMINAL INVESTIGATION?

• The individuality of any fingerprint is based not
  upon the general shape or pattern that it forms,
  but instead upon its ridge structure and specific
  characteristics (also known as minutiae).
• There are at least 150 individual ridge
  characteristics on the average fingerprint.
• In a judicial proceeding, a point-by-point
  comparison must be graphically demonstrated for
  at least 12 different, but corresponding, points
  in order to prove the identity of a specific
  person.

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Types of fingerprints

• There are three types of fingerprints that exist
  at crime scenes. 
• visible prints are made from finger stained with
  colored materials such as ink, blood, and
  grease. 
• plastic prints are formed by pressing onto a soft
  surface such as clay, soap, and wax. 
• Latent prints are invisible prints left on an
  object by the bodys natural greases and oils. 
• Because it cannot be seen by naked eyes,
  fingerprint powders, chemicals, and even lasers
  are used to make it visible on the crime scene
  evidence. 

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Fingerprint categorization

• The fingerprints can be categorized into three
  basic formations
• Loops
• Arches
• Whorls

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Why do people leave fingerprints

• The sweat glands in the skin of your finger tips
  produce a water based oil solution that coats the
  ridges of your print.
• These ridges retain a portion of this solution
  such that when the finger makes contact with a
  surface, a residue is left behind which is a
  facsimile of your print (i.e., latent print).
• Fingerprint patterns are divided into three main
  groups consisting of Arches, Loops and Whorls.

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Arches

• Arches (5)
• Arches are lines that start on one side of the
  print, rise into hills and then exit on the other
  side of the print.

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Whorl

• Whorl (30)
• Whorl is circles that do not exit on either side
  of the print.  

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Loops

• Loops (65)
• Loops are lines that enter and exit on the same
  side of the print. 

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Further Classification
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Further Classification
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Good Prints

• Fingerprint scan quality can affect the
  reliability of any electronic fingerprint system.
  
• In general, automated fingerprint analysis
  systems work by creating a computer model of the
  live print scan.
• This model is based on many of the features found
  to be common in fingerprints and is sometimes
  referred to as a template.
• The process of creating this model/template is
  usually referred to as a 'Registration' process.
• The process of matching a live print scan to a
  model/template is generally referred to as a
  'Lookup'.

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Common Line Types (Shapes) Found in Fingerprints

• Fingerprint patterns are made up of 'line-types'
  (shapes) which determine the general
  classification characteristics of the print
  (i.e., Arch, Loop or Whorl).
• The 'Pattern Area', is a term used to describe
  the center area of a print which contains many of
  the line-types previously described.
• This area and its contents determine the
  classification of the print (i.e., Arch, Loop,
  Whorl, etc.).

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Line-types found in prints

• ROD-A Rod generally forms a straight line. It has
  little to no recurve features and tends to be
  found in the center of the fingerprint's pattern
  area.
• ELLIPSE-An Ellipse is a circular or oval shaped
  line-type which is generally found in the center
  of Whorl patterns.

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Line-types found in prints

• SPIRAL-A Spiral line-type spirals out from the
  center of the fingerprint and is generally found
  in Whorl print patterns.
  
• BIFURCATION-Is the intersection of two or more
  line-types which converge or diverge.

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Line-types found in prints

• TENTED ARCH-Resembles a tent. This line-type
  quickly rises and falls at a steep angle. They
  tend to be associated with Tented Arch pattern
  prints.  
• LOOP-A Loop is a recurve line-type that enters
  and leaves from the same side of the fingerprint.

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Line-types found in prints

• ISLAND-An Island is a line-type which stands
  alone. (i.e., does not touch another line-type
  and is totally contained in the pattern area of
  interest.)  
• SWEAT GLAND-The finger contains many sweat
  glands. The moisture and oils they produce
  actually allow the fingerprint to be
  electronically imaged.

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Line-types found in prints

• MINUTIAE POINTS - Is the term used to define
  common micro features in a finger print.
• Common minutiae points are the intersection of
  Bifurcations, ending points of Islands and the
  center point of the sweat glands.

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Integrated Automated Fingerprint Identification
System or IAFIS

• The Integrated Automated Fingerprint
  Identification System
• More commonly known as IAFIS
• National fingerprint and criminal history system
  maintained by the Federal Bureau of Investigation
  (FBI), Criminal Justice Information Services
  (CJIS) Division.
• IAFIS 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.

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Henry System

• United States uses a modified 10 point Henry
  system all ten fingerprints from a person are
  reviewed
• Parts of the Henry System are
• Key
• Major
• Primary
• Secondary
• Subsecondary
• Final
• Please refer to page 348 table 17.11 for and
  explanation of each of these parts.

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Typical Ten Print Card
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Law Enforcement Information Systems

• AFIS is part of one of three systems in use in
  the U.S. . The other two are
• Combined DNA Indexing System (CODIS)
• Integrated Ballistics Identification System
• (IBIS)

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Law Enforcement Information Systems

• All three systems (AFIS, CODIS and IBIS) all have
  two types of files
• Knowns- files of known suspects, prints,
  specimens, images, etc
• Forensic Files images of unknown images,
  suspects, cases, etc and of which the sources are
  not known

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Development of Latent Prints

• Fingerprint residue, which is composed of
  inorganic and organic residues, comes from
  eccrine glands and from touching areas where
  apocrine glands in body are before touching item
• Fingerprints can also come from touching external
  sources- oils, tars, etc and then touching
  surface of object

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Physical Methods

• Latent fingerprint powder dusting is primary
  method of visualizing fingerprints
• Black fingerprint powders generally have best
  results
• Magnetic powders and brushes are now available
• Small particle reagent (SPR) is sprayed on print
  and adheres to lipids from prints

47
Chemical Methods

• Chemical methods of techniques for visualizing
  fingerprints are
• Silver nitrate rarely used anymore
• Iodine fuming very common dirty brown colored
  print and needs to photographed quickly as it
  fades

48
Chemical Methods

• Ninhydrin used since 1910 and is slow to react
  unless heat and humidity are present develops
  bluish-purple prints
• Cyanoracrylate (superglue) is used to fume and
  yields an off white colored print use of heat
  and humidity accelerates process

49
Chemical Methods

• Physical Developer (PD) photographic type process
  based on deposition of silver onto latent
  fingerprint residue
• US Secret Service modified procedure and uses
  colloidal gold to enhance prints
• Normally used after ninhydrin

50
Combination and Special Lighting

• Various types of lights are used to illuminate
  fingerprints
• Bright white light (525 nanometers), lasers, and
  black lights with the use of fluorescent powders
  are commonly used

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Bloody Fingerprints and Other Special Situations

• Bloody fingerprints normally are not latent
  primarily composed of blood
• Most processes for latent print chemical
  enhancement do not interfere with blood
  collection for DNA profiling by PCR for CODIS
• Many bloody fingerprints are enhanced by
  peroxidase- reaction chemicals

52
Bloody Fingerprints and Other Special Situations

• Fingerprints that are on tape, especially the
  sticky side, were developed by crystal violet
• Most common method today is sticky side powder,
  which is composed of lycopodium (plant pollen)
  that is mixed with detergent and water

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Same Print?
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Systematic Approaches

• Latent development is completed by
• Utilizing latent development technique which
  maximizes numbers of prints
• Using least destructive developing process first
• Approaches vary depending on surface texture
  (porous v. nonporous)

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Recognition, Collection and Preservation of
Fingerprint Evidence

• Fingerprints are among best evidence
• Objects at a crime scene which are believed to
  contain prints should be collected
• If collection is impossible, latent development
  techniques should be used
• Photographing of developed prints is advisable

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Test Tomorrow!!!