Fingerprints

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Fingerprints
Photos from Kendall Hunt Publishing Content from
Chapter 4 in Forensic Science for High School
Students and numerous other sources
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Bertillon Signalment

• In the late 1800s Alphonse Bertillons method of
  identification became popular.
• With photos people could now be IDd
• Method required many instruments and took much
  training to be accurate
• Inaccuracy was major issue
• Measurements standing height, wing span, trunk
  sitting, head length width, each ear, left
  foot, left middle finger, left forearm

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DactyloscopyThe Study of Fingerprints

• History
• William Herschelrequired Indians to put their
  fingerprints on contracts, and used fingerprints
  as a means of identifying prisoners
• Henry Fauldsclaimed that fingerprints did not
  change over time and that they could be
  classified for identification
• Alphonse Bertillonproposed body measurements as
  a means of identification termed anthropometry
• Francis Galton published Finger Prints in 1892
  after extensive research
• -identified anatomy
• -methods of recording
• -pattern types loops, arches, and whorls
• -estimated 64 billion possibilities
• -theorized 3 principles

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DactyloscopyThe Study of Fingerprints

• History
• Edward Richard Henryin collaboration with
  Galton, instituted a numerical classification
  system
• Juan Vucetichdeveloped a fingerprint
  classification system based on Galtons that is
  used in Spanish-speaking countries
• 1924-US consolidates Bureau of Investigation
  files with Leavenworth Prison files as FBI formed
• Today the FBI has the largest collection of
  prints in the world with 700,000,000 individuals

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Fundamental Principles of Fingerprints

1. A fingerprint is an individual characteristic.
2. A fingerprint remains unchanged during an
   individuals lifetime.
3. Fingerprints have general characteristic ridge
   patterns that permit them to be systematically
   classified.

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1. A fingerprint is an individual characteristic.

• Minutiae-ridge characteristics
• -150 individual minutiae per finger
• -Most prints are partial
• - 8 to 12 are needed for match
• Ridge Counts - of ridges between Delta and core
• -only in loop prints
• A balloon will help you see it

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Minutiae
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Fingerprint Minutiae
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2. Fingerprints remain unchangedThe dermal
papillae develops as fetus, except growth, it
never changesImpossible to obliterate, even
scars would provide unique printsPrimates have
prints
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3. Fingerprints have general characteristic ridge
patterns that permit them to be systematically
classified.LAW Loops 60 Ulnar
Radial Arches 6 Tented PlainWhorls
34 Plain Central Pocket Double
Loop Accidental
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Loop Looks like a LAKE

• A loop must have one or more ridges entering and
  exiting from the same side. Loops must have one
  delta.
• Types
• Radialopens toward the thumb
• Right On!
• Ulnaropens toward the pinky (little finger)
• Under
• Which type of loop is this, if it is on the right
  hand? Left hand?

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Arch

• An arch has friction ridges that enter on one
  side of the finger and cross to the other side
  while rising upward in the middle. They do NOT
  have type lines, deltas, or cores.
• Types
• Plain Bike rider wont blow out a tire
• Tented spike in the road

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Whorl

• A plain or central pocket whorl has at least one
  ridge that makes a complete circuit. A double
  loop is made of two loops. An accidental is a
  pattern not covered by other categories. Whorls
  have at least two deltas and a core.
• Types
• Plain
• Central pocket
• Double loop
• Accidental

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Plain Whorl

• Arrow through the delta must cross at least one
  circle
• Deltas are more symmetrical

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Central Pocket Loop Whorl

• 1 Circle, 2 Deltas and arrow does not cross a
  circle
• Delta is usually off balance

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Double Loop Whorl

• 2 loops inside 2 deltas
• Looks like a wave or Yin/Yang

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Accidental Whorl

• 3 deltas or combination of tented loop arch
• Basically a mess

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LOOP
WHORL
ARCH
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Primary Classification
The Henry-FBI Classification System Each finger
is given a point value.
right
left
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Primary Classification, continued

• Assign the number of points for each finger
  that has a whorl and substitute into the equation

right right left left left
index ring thumb middle little 1

right right right left left
thumb middle little index ring 1
That number is your primary classification number.
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Comparison

• There are no legal requirements in the United
  States on the number of points required for a
  match. Generally, criminal courts will accept 8
  to 12 points of similarity.

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Latent Prints

• Latent fingerprints are those that are not
  visible to the naked eye. These prints consist of
  the natural secretions of human skin and require
  development for them to become visible.
• Most secretions come from three glands
• Eccrinesecretes largely water, with both
  inorganic (ammonia, chlorides, metal ions,
  phosphates) and organic (amino acids, lactic
  acids, urea, sugars) compounds. Most important
  for fingerprints.
• Apocrinesecretes pheromones and other organic
  materials.
• Sebaceoussecretes fatty or greasy substances.

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Developing Latent Prints

• Developing a print requires substances that
  interact with secretions, causing the print to
  stand out against its background. It may be
  necessary to attempt more than one technique,
  done in a particular order so as not to destroy
  the print.

• Powdersadhere to both water and fatty deposits.
  Choose a color
• to contrast with the background.
• Iodinefumes react with oils and fats to produce
  a
• temporary yellow-brown color.

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Developing Latent Prints, continued

• Ninhydrinreacts with amino acids to produce a
  purple color.
• Silver nitratereacts with chloride to form
  silver chloride, a material that turns gray
  when exposed to light.
• Cyanoacrylatesuperglue fumes react with water
  and other fingerprint constituents to form a
  hard, whitish deposit.
• In modern labs and criminal investigations,
  lasers and alternative light sources are used to
  view latent fingerprints. These were first used
  by the FBI in 1978. Since lasers can damage the
  retina of the eye, special precautions must be
  taken.

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Iodine Fingerprint
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Ninhydrin Fingerprint
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Cyanoacrylate Fingerprints
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Other Prints

• Lipsseveral common patterns
• Voiceelectronic pulses measured on a
  spectrograph
• Footsize of foot and toes friction ridges on
  the foot
• Shoescan be compared and identified by type of
  shoe, brand, size, year of purchase, and wear
  pattern

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Other Prints, continued

• Palmfriction ridges can be identified and may be
  used against suspects

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Other Prints, continued

• Footprints are taken at birth as a means of
  identification of infants.

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Other Prints, continued
Earprint catches murderer

• A man has been convicted of suffocating an eldery
  woman on the basis of earprint evidence. The
  assailant was caught after police matched the
  inprint of his ear on the victims window. Police
  believe that the thief put his ear to the window
  to listen for signs of anyone home.

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Other Prints, continued

• Teethbite marks are unique and can be used to
  identify suspects. These imprints were placed in
  gum and could be matched to crime scene evidence.

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Other Prints, continued

• The blood vessel patterns in the eye may be
  unique to individuals. They are used today for
  various security purposes.

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AFIS

• The Automated Fingerprint Identification Systema
  computer system for storing and retrieving
  fingerprints
• Established in the 1970s, AFIS enables law
  enforcement officials to
• Search large files for a set of prints taken
  from an individual
• Compare a single print, usually a latent print
  developed from a crime scene
• By the 1990s, most large jurisdictions had their
  own system in place. The problem A persons
  fingerprints may be in one AFIS database but not
  in others.
• IAFISthe FBIs Integrated Automated Fingerprint
  Identification System, which is a national
  database of all 10-print cards from all over the
  country

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Biometrics

• Use of some type of body metrics for the purpose
  of identification. (The Bertillon system may
  actually have been the first biometry system.)
• Used today in conjunction with AFIS.
• Examples include retinal or iris patterns, voice
  recognition, hand geometry.
• Other functions for biometrics can be used to
  control entry or access to computers or other
  structures can identify a person for security
  purposes can help prevent identity theft or
  control social services fraud.

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Developing Prints - basics

• A little powder goes a long way!
• Gentle! You can obliterate prints
• Applying powder is the art of the job some
  swirl others up/down side to side
• Lift best print first

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Rolling Finger Prints

• Media Sheet How to Take Prints
• Video goes quickly so pay attention
• Completed worksheet serves as your lab
  instruction guide

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Rolling Finger Prints

• Reminders
• A little ink goes a long way
• Nail edge to nail edge!
• Dont change pressure or course
• Have person RELAX!
• Hands lower than inking surface

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Rolling Finger Prints