FORENSIC SCIENCE Prints

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FORENSIC SCIENCEPrints

• GOAL
• Produce a print portfolio that explains print
  information and demonstrates your best work in
  lifting and identifying a variety of prints.

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BERTILLON SYSTEM
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Prints

• Making Prints
• Rolling prints
• Modus Operandi--primary identification number
• Lifting Prints
• Black, white and fluorescent powder
• Chemicals--ninhydrin, iodine, silver nitrate,
  cyanoacrylate
• Other Types of Prints
• Palm, lip, teeth, eye, ear, voice, shoe and feet
  prints

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Fundamental Principlesof Fingerprints

• A fingerprint is an individual characteristic.
• A fingerprint will remain unchanged during an
  individuals lifetime.
• Fingerprints have general characteristics ridge
  patterns that permit them to be systematically
  classified.

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Ridge Characteristics

• Minutia--lines of the fingerprint
• ridge ending
• bifurcation
• short ridge
• dot or fragment
• island
• enclosure

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MINUTIA

• RIDGE ENDING

BIFURCATION
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MINUTIA

• SHORT RIDGE

DOT or FRAGMENT
ISLAND
ENCLOSURE
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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
• Tented

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Loop

• A loop must have one or more ridges entering and
  exiting from the same side it began. Loops must
  have one delta.
• Types
• Radial--opens toward the thumb
• Ulnar--opens toward the pinky (little finger)
• Which type of loop is this, if on the right hand?
  Left hand?

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Whorl

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

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Can You See the Differences?
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Primary Identification Numbers
Fingers are numbers 1 through 10 starting with
the thumb on the right hand and continuing
through with the thumb on left hand. Each finger
is then given a point value as seen in the chart
below.
1. right 2. right 3. right
4. right 5. right thumb
index middle ring
little 16 16
8 8 4
6. left 7. left 8. left
9. left 10. left thumb
index middle ring
little 4 2
2 1 1
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Primary Identification (cont)
Set up a ratio of even numbered fingers over odd
numbered, adding one in both the numerator and
denominator.
2. right 4. right 6. left
8. left 10. left index
ring thumb ring
little 16 8
4 2 1
1 1

16 8 4
2 1 1. right
3. right 5. right 7. left
9. left thumb middle
little index little
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Fingers
2
8
2
1
16
8
4
1
16
4
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Latent Prints

• Latent fingerprints are those that are hidden
  and are not visible to the naked eye. These
  prints consist only of the natural secretions of
  human skin and require treatment to cause them to
  become visible.
• Most secretions come from three glands
• Eccrine--largely water with both inorganic
  (ammonia, chlorides, metal ions, phosphates) and
  organic compounds (amino acids, lactic acids,
  urea sugars)
• Apocrine--secrete cytoplasm and nuclear materials
• Sebaceous --secrete fatty or greasy substances.

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Lifting Latent Prints

• Developing a print requires chemicals that react
  with secretions that cause 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.
• Powders--adhere to both water and fatty deposits.
  Choose a color to contrast the background.
• Iodine--fumes react with oils and fats to produce
  a temporary yellow brown reaction.

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Iodine Fingerprint
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Ninhydrin Fingerprint
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Lifting Latent Prints (cont)

• Ninhydrin--reacts with amino acids to produce a
  purple reaction.
• Silver nitrate--react with chlorides to form
  silver chloride, a material which turns gray
  when exposed to light.
• Cyanoacrylate--super glue 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. It was first used by
  the FBI in 1978. Since lasers can damage the
  retina of the eye, special precautions must be
  taken and a filter used.

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Cyanoacrylate Fingerprints
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Other Prints

• Ears--shape, length and width
• Face--pictures being used in Florida to find
  criminals
• Voice--electronic pulses measured on a
  spectrograph
• Feet--size of foot and toes lines of the feet
• Shoes--can be compared and identified by type of
  shoe, brand, size and year of purchase

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Other Prints

• Palm--lines can be identified and may be used
  against suspects.

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Other Prints

• Foot Prints are taken at birth as a means of
  identification for infants.

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Other Prints

• Lips--display one of five common patterns
• Short vertical lines
• Long vertical lines
• Rectangular lines that may crisscross
• Diamond
• Branching

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(No Transcript)
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Other Prints

• Teeth--bite 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

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

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Other Prints Iris Scans

• Advantages Unique to individual, easy to access,
  protected by cornea
• Disadvantages expense distance not left at a
  scene

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Fingered with the wrong print

• On March 11, 2004 a train was bombed in Madrid,
  Spain.
• 5 suspects
• 7 points of minutia
• digital on-screen image
• detained an American lawyer for 2 weeks

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FBI Apologizes

• Brandon Mayfield was released
• A series of mistakes led to the detaining of Mr.
  Mayfield
• FBI and Spanish police conducted an investigation
• How many points of minutia are necessary for a
  print to be considered individualized?

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FINGEREDCrazy Criminals

• A New Jersey resident phoned police after finding
  her back door slightly ajar with a muddy palm
  print on the glass. When the officer questioned
  the woman, it was determined that she had been
  gardening. When he compared her hand with the
  lifted print, he had a match!!

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PORTFOLIO

• A portfolio is a collection of work that
  demonstrates what you know and can do. It shows
  your best work. In this unit, you will put
  together a portfolio of your work on making and
  lifting various prints. You will add to your
  portfolio as you work through the labs in class
  and put it in to a final form at home. You will
  be given both written instructions and an
  assessment list.