Fingerprints and other Personal Identification Patterns

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Chapter 6
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Fingerprints and other Personal Identification
Patterns

• Chapter Objectives
• Fingerprints an old and traditionally valuable
  type of evidence
• About fingerprints - their nature and the history
  and development of their use
• Fingerprint classification, management of large
  files, AFIS
• Collection preservation of fingerprint evidence
• Latent prints and their development
• Fingerprint comparison and identification
• The fingerprint identification profession
• Other patterns for personal identification
• Identification of human remains handling of
  mass disasters

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I. Fingerprints An old and Traditionally
Valuable Type of Evidence

• Fingerprints belong to the individualization
  pattern category
• 2-dimensional fingerprints are termed residue
  prints
• 3-dimensional fingerprints are termed plastic or
  impression prints
• Used primarily to help locate, identify, and
  eliminate suspects and to identify human remains

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II. About Fingerprints Their Nature the
History Development of their Use

• 1. Nature of Fingerprints
• The basis for personal identification
• Every fingerprint is unique to an individual
• Fingerprints do not change throughout life
• They can be classified
• Fingertips, palms, and soles of feet have
  friction ridge skin which form complicated
  patterns
• The ridges are called hills and valleys are
  called furrows

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II. About Fingerprints Their Nature the
History Development of their Use

• The basic fingerprint patterns are arches, loops
  and whorls
• Each basic pattern has subcategories, and loop
  and whorl patterns have definable features
  known as the core and delta

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II. About Fingerprints Their Nature the
History Development of their Use

• Minutiae are ridge features that individualize
  the overall pattern
• Minutiae include ridge endings, bifurcations, and
  dots

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II. About Fingerprints Their Nature the
History Development of their Use

• 2. History and Development of their Use
• Methods for identifying fingerprints were
  developed in Europe in the 17th and 18th
  centuries
• Czech physiologist Johannes Purkinje described
  fingerprint patterns in 1823
• Sir William Hershel recognized the value of
  fingerprints for personal identification while
  working in India in 1953
• Dr. Henry Faulds, a Scottish physician, studied
  fingerprints while working in India and Japan in
  the 1870s, noting that they could be classified

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II. About Fingerprints Their Nature the
History Development of their Use

• Sir Francis Galton, scientist and geneticist,
  authored the book Finger Prints published in 1892
• In 1893, Scotland Yard added fingerprints to the
  Bertillon cards being used for criminal
  identification
• Juan Vucetich of Argentina, published a book on
  fingerprints in 1894, and devised a
  classification system
• Sir William Henry, developed a classification
  system which was used in the UK in the early
  1900s
• New York City began to use fingerprints in 1903,
  shortly afterwards, the NY State Prison System
  began to use fingerprints

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III. Fingerprint Classification, Management of
Large Files, AFISs

• Classification systems are based on the 10-print
  fingerprint set
• The system enabled efficient searching of a
  large fingerprint file to determine if the new
  10-print set was already there, but was not
  useful when searching for the presence of a
  single crime scene print

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III. Fingerprint Classification, Management of
Large Files, AFISs

• In the US and UK, the classification system is a
  variant of the one Sir Henry developed
• Argentina and other South American countries, use
  a system based on the one developed by Vucetich
• Computer based search systems enable searches for
  single or partial prints

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III. Fingerprint Classification, Management of
Large Files, AFISs

• Automated Fingerprint Identification Systems
  (AFIS) are computer systems which can scan,
  store, and retrieve single fingerprints
• The FBI maintains a national system called IAFIS
  (Integrated AFIS)

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III. Fingerprint Classification, Management of
Large Files, AFISs

• Two applications search for a 10-print record
  and search for the presence of a single print
• AFIS has two types of files Known (10-print from
  individuals) and Forensic (crime scene prints
  from an unknown source)

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IV. Collection and Preservation of Fingerprint
Evidence

• Items with latent (not visible) fingerprints are
  usually collected and submitted to a forensic lab
  for processing
• If the latent fingerprints are on items that are
  difficult to collect, then the prints are
  developed at the scene
• Latent fingerprint developed using powder-dusting
  are collected by tape lifting
• With other techniques, the developed prints
  should be photographed then lifted or the
  entire item submitted to the lab

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V. Latent Prints Their Development

• 1. Types of Evidentiary Fingerprints
• Three types of crime scene prints visible,
  plastic, and latent
• A visible (patent) print does not require any
  enhancement or development to be recognized as a
  fingerprint
• A plastic print is a 3-dimensional fingerprint
  indentation in a soft receiving surface
• A latent print is one that requires development
  to be rendered clearly visible

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Patent/Plastic Prints

• Made in some material
• Blood, grease, mud, etc.
• Negative of positive print
• Positive take material to the surface
• Negative material already on surface

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V. Latent Prints Their Development

• 2. Development of Latent Fingerprints
• Sweat glands secrete their fluids onto the
  surface of the skin via pores on the ridges
• Latent print develop-ment techniques use
  methods to target one or more of the residue
  components

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V. Latent Prints Their Development

• Oils from other sweat glands and material from
  contact with various surfaces contribute to the
  fingerprint residue composition
• Methods to develop latent prints were devised
  based on the knowledge of latent print residue
  composition
• The methods used fall into three groups
  physical, chemical, and combination or special
  illumination methods

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V. Latent Prints Their Development

• Physical Methods
• Physical methods involve the application of
  particles which adhere to the print residues
• The best known physical method is powder dusting
  using black or gray powder, but other colors are
  available
• Dusted prints are tape lifted and placed on a
  surface of contrasting color to the powder

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V. Latent Prints Their Development

• Physical Methods
• Using a magnetic brush to apply a magnetic
  powder is a gentler physical method for
  developing prints
• Small particle reagent (SPR) is a formulation of
  small inorganic particles in suspension applied
  by spraying or dipping and used on prints that
  have been exposed to moisture

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V. Latent Prints Their Development

• Chemical Methods
• Iodine fuming is a development technique in which
  solid iodine sublimes to a vapor, which then
  interacts with oily residues to give a deep brown
  print
• Iodine fuming is useful for prints on porous
  surfaces
• Iodine prints are not stable and must be
  photographed to document and preserve

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V. Latent Prints Their Development

• Chemical Methods
• Ninhydrin reacts with amino acids found in
  fingerprint residues to yield a bluish-purple
  colored compound, Ruhemanns purple
• The reagent reacts slowly and must be accelerated
  by heat and moisture
• Ninhydrin is useful on porous surfaces such as
  paper

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V. Latent Prints Their Development

• Chemical Methods
• Super Glue (cyanoacrylate) fumes, formed by
  heating or strong alkali, interact with latent
  print residues and produce an off-white polymer
  on the friction ridges
• Super glue developed prints are usually further
  enhanced with powders or dyes

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V. Latent Prints Their Development

• Chemical Methods
• Physical developer is a chemical reagent which
  forms metallic silver on the latent prints by
  reacting with the fatty materials (lipids) in the
  residue

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V. Latent Prints Their Development

• Illumination and Combination Methods
• Oblique angle lighting, usually with high
  intensity alternative light sources of
  different wavelengths, may improve the visibility
  of latent prints
• Laser light can be used to excite chemically
  treated prints which then fluoresce

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V. Latent Prints Their Development

• Bloody fingerprints other situations
• Bloody fingerprints are not really latent but
  may have poor ridge features and require
  enhancement with chemical reagents
• Many of these reagents are based on the
  peroxidase enzyme catalyzed reaction used in
  presumptive blood testing
• Fingerprints deposited on tape can be enhanced
  using staining dyes such as crystal violet or
  sticky side powder, a pollen based powder
• Fingerprints on skin may be difficult to enhance

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V. Latent Prints Their Development

• Systematic Approaches
• Systematic approaches depend on the nature of
  the surface on which the latent print is
  located

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V. Latent Prints Their Development

• Systematic Approaches

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VI. Fingerprint Comparison and Identification

• Crime scene prints can vary in quality and are
  first evaluated for their comparison suitability
• The ACE-V method refers to the four steps used
  in the analysis and comparison of a latent print
  with a known analysis, comparison, evaluation,
  and verification
• Comparisons involve several examination levels
  I, II, and III

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VI. Fingerprint Comparison and Identification

• Level I detail refers to the overall pattern
  ridge flow
• Level II detail refers to the comparison of
  minutiae
• Level III detail refers to the pore numbers,
  locations, and shape size of ridge features
• An identification is made if every feature on a
  crime scene print is consistent with the Known
• If there are unexplained differences with the
  Known, an exclusion is reported
• If there are not enough features for a definite
  conclusion, an inconclusive is reported

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VII. The Fingerprint Identification Profession

• The IAI (International Association for
  Identification) is the primary peer
  standard-setting group in the identification
  sciences, with a certification program for latent
  print examiners
• SWGFAST (Scientific Working Group on Friction
  Ridge Analysis, Study and Technology) started in
  1995 with the purpose of establishing consensus
  standards for the profession

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VIII. Other Patterns for Person Identification

• Palm and Sole Prints
• Palms of the hands and soles of the feet have
  friction ridge skin features
• Palm and sole prints are handled exactly like
  fingerprints, but no databases exist for these
  prints
• Skeletal Features
• X-ray images of sinus cavities, the dentition,
  spongy long-bone tissue, fractures and healed
  fractures are used by forensic anthropologists,
  radiologists, and odontologists to identify
  skeletal remains
• Features on the skeletal remains are usually
  limited to class level identification

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VIII. Other Patterns for Person Identification

• Bite Marks
• Bite marks are produced by human teeth into skin
  and flesh and into food items
• The human dentition has considerable
  individuality and are compared and evaluated by
  forensic odontologists

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VIII. Other Patterns for Person Identification

• Lip Ear Prints
• Both lips and ears are capable of producing
  impression patterns that can be compared, but
  such cases are unusual and rare
• Voice Identification
• Voice prints represent a record of a persons
  speech pattern
• Sound spectrograms (voice prints) are used to
  compare Q and K voice patterns

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VIII. Other Patterns for Person Identification

• Biometrics
• Biometrics refers to the measurement of some part
  or features of the human body for the purpose of
  verification or identification
• Biometric methods include fingerprints, iris
  scans, retinal scans, and facial scans
• Biometric systems extract a number of features
  from a complex pattern for comparison to database
  information
• Verification refers to the ability to distinguish
  between individuals of a large group

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IX. Identification of Human Remains Handling of
Mass Disasters

• Biometrics
• Both destruction and fragmentation of the human
  body can be issues in mass disasters
• Direct methods include visual identification by
  relatives, dental and fingerprint comparisons,
  and DNA profiling
• Indirect methods include clothing and personal
  items, marks, scars, tattoos, artificial limbs,
  anthropological features, medical devices, and
  facial reconstructions