1. Chapter 4: Fingerprints
“Fingerprints can not lie,
but liars can make fingerprints.”
—Unknown

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Fingerprints
Students will learn:
Why fingerprints are individual evidence.
Why there may be no fingerprint evidence at a crime scene.
How computers have made personal identification easier.
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3. Students will be able to:
Fingerprints
Students will be able to:
Define the three basic properties that allow individual identification by fingerprints.
Obtain an inked, readable fingerprint for each finger.
Recognize the general ridge patterns (loops, whorls, and arches)
Identify friction ridge characteristics and compare two fingerprints with at least ten points of identification.
Explain the differences among latent, plastic, and visible fingerprints.
Develop latent prints (make them visible) using physical and chemical methods.
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Fingerprints
Recording Prints
rolling inked prints
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 footprints
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5. Dactyloscopy The study of fingerprints
Historically
William Herschel—required Indians to put their fingerprints on contracts, and also as a means of identifying prisoners
Henry Faulds—claimed that fingerprints did not change over time and that they could be classified for identification
Alphonse Bertillon—proposed body measurements as a means of identification; termed anthropometry
Francis Galton—developed a primary classification scheme based on loops, arches and whorls.
Edward Richard Henry—in collaboration with Galton instituted a numerical classification system
Juan Vucetich—developed a fingerprint classification based on Galton’s that is used in Spanish-speaking countries
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6. Fundamental Principles of Fingerprints
A fingerprint is an individual characteristic.
A fingerprint will remain unchanged during an individual’s lifetime.
Fingerprints have general characteristic ridge patterns that permit them to be systematically classified.
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7. Fundamental Principles of Fingerprints
Beginning the 10th week of gestation, fingerprints are formed in the basal layer influenced by the environment surrounding the fetus.
Fingerprints are covered with hundreds of microscopic sweat pores which aid in gripping.
Fingerprints are a mixture of mainly water, but also oils, salts, and dirt from every day activities.
Basal layer

8. Composition of Fingerprints
Sweat
% water
% solids
50% organic solids (mostly amino acids)
50% inorganic solids (NaCl and KCl)
Contaminants
Bodily fluids (blood, saliva, nasal secretions, semen, etc.)
Oils and fats (sebum)

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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 (ridges that diverge or separate), deltas (located at the point of divergence), or cores (center of the loop). 5% of the total population have arches
Types
Plain (4%)
Tented (1%)
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10. Loop
A loop must have one or more ridges entering and exiting from the same side. Loops must have one delta. 65%
Types
Radial—opens toward the thumb (10%)
Ulnar—opens toward the “pinky” (little finger) (55%)
Which type of loop is this, if it is on the right hand? Left hand?

11. 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. (30%)
Types
Plain (24%)
Central Pocket (2%)
Double Loop (4%)
Accidental (0.01%)

12. Ridge Characteristics
Minutiae—characteristics of ridge patterns
Ridge ending
Short ridge
Dot or fragment
Bifurcation
Double bifurcation
Trifurcation
Bridge
Island
Enclosure
Spur
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Fingerprint Minutiae
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Basic Fingerprints
Behind the Badge
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15. Primary Classification
The Henry—FBI Classification
Each finger is given a point value
right
left
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16. Primary Classification
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 =
right right right left left
thumb middle little index ring
That number is your primary classification number
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17. Taking Legible Prints Be confident! Practice, Practice, Practice!
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18. Required Supplies Ink pad, or ink and roller
Tenprint card (purchased or self-made)
Area for printing, or stand (purchased)
Hand soap and clean-up supplies
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Trade & Industrial Education

19. Step 1: Communicate Tell the subject
You are going to take their prints
To relax their hands
To let you do all the work
Added these for parallelism.
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20. Step 1: Communicate When they try to “help” Stop Advise them again
Ask them to let you control their hands
Stop and reiterate this as necessary

21. Step 2: Rolled Prints Ink slab and roller
Roll just enough ink on the slab
Roll each finger from the thumb to the pinkie on the slab
Roll fingers, one-by-one, onto the Tenprint card, without pressing down.
Print should be wide and not resemble typical finger sizes

22. Step 3: Plain Impressions
Ink them from the top down until the fingers lay flat.
Do the left and then the right fingers.
Ink the thumbs.
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23. Step 4: Clean Up When removing ink from fingers:
Soap MUST be rubbed in well
Move the print card
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24. Special Situations Examples: Amputations Bandaged Fingers or Hands
Scars
Deformities
Worn Fingerprints
Extra Fingers
Webbed Fingers
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25. Comparison
Prior to the use of computers and scanners, fingerprints were identified by people comparing ridge patterns and minutiae points. Now, computers narrow the search and final identification is completed by a fingerprint examiner.
There are no legal requirements in the United States on the number of points. 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:
Eccrine—largely water with both inorganic (ammonia, chlorides, metal ions, phosphates) and organic compounds (amino acids, lactic acids, urea, sugars). Most important for fingerprints.
Apocrine—secrete pheromones and other organic materials.
Sebaceous—secrete fatty or greasy substances.
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27. Latent Prints
Friction ridges on the inner surfaces of fingers, palms, and soles of feet have tiny pores that are the outlet openings of sweat glands which secrete sweat that is poor in oils. However, when fingers touch other areas of the body that secrete more oil-rich sweat, such as the hair, fingers pick up oils, salts and grime. Fingers deposit these residues when the finger pads contact another surface.
Therefore, recently washed hands will leave fainter latent prints.
From a dead body, fingerprints may be treated chemically to help them puff out or the skin may be removed and placed on a gloved finger of someone else who can then roll the prints.

28. Fingerprint Powders (continued)
Gray and black powders – the most common, chosen to make the best contrast with the surface
Magnetic powder – applied with a special brush on leather and rough plastic surfaces.
Fluorescent powders – used to photograph latent prints on multi-colored surfaces. They fluoresce under ultraviolet light.

29. Fingerprint Chemicals
Ninhydrin – reacts with amino acids in sweat to form purple-blue prints. A 0.6% solution (in ethanol) is sprayed onto porous surfaces such as paper.

30. Fingerprint Chemicals (continued)
Physical Developer – silver nitrate-based liquid reagent used on porous surfaces. It is often used as the last resort because it destroys protein.
Cyanoacrylate (superglue) fuming – developed in 1982 by Japanese Police. It is used on a variety of materials not only to visualize latent prints, but also to semi-permanently affix them to the surface.

31. Cyanoacrylate Fingerprints
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32. Fingerprint Chemicals (continued)
DFO (1,8-diazafluotrn-9-one) – newer replacement chemical for ninhydrin. It is 2.5 times more sensitive than ninhydrin.
Rhodamine 6G is a fluorescent dye that may be used after cyanoacrylate fuming to visualize latent prints under laser light.

33. Fingerprint Chemicals (continued)
Iodine fuming – one of the oldest latent print development methods. Solid iodine crystals sublimate and the vapor will react with fatty oils and some sweat residue. Iodine prints are not permanent and will begin to fade once the fuming process is stopped.

34. Fingerprint Chemicals (continued)
Gentian violet (or crystal violet) – used for developing latent prints on the adhesive side of tape. An aqueous solution of crystal violet is sprayed directly onto the adhesive.
Amido Black – protein dye stain that can develop faint bloody fingerprints on porous and nonporous surfaces.

35. Fingerprint Chemicals (continued)
LCV (Leuco Crystal Violet) – a protein stain spray that can develop faint or invisible bloody fingerprints on non-porous surfaces

36. Trends with Fingerprints
It is NOT possible to determine the age, sex or race of an individual solely from their fingerprints. However:
Statistically in young adults, friction ridges of women are significantly finer than those of men.
Fine ridges may be found in the very young and the very old.
Manual labor tends to strengthen ridges.
Women tend to perspire at a lower rate than men.
Sodium chloride (NaCl) is lower for women.
Creases are more common in women's FPs.

37. Preservation of Developed Latent Prints
Photograph
Covering the print to preserve it in its entirety (if on a small object)
Lifting the prints with adhesive tape and placing the tape with prints on a card with labels

38. Factors Affecting Fingerprints
Age – thinner epidermis, flattening of dermal papillae, creases, etc.
Fine ridge structure – less skin contact leads to a spotty appearance.
Stimuli – sweating can be due to warmth, exertion, fever, drugs, anxiety, tension, pain, or spicy foods.
Occupational and medical condition – teaching, and other positions in which a person handles or shuffles papers, can cause fine ridge structure.

39. Factors Affecting Fingerprints (continued)
Transposal factors
Receiving surface texture
Contaminants on the hands
Contaminants on the receiving surface
The manner of contact
The amount of pressure
Environmental factors
Temperature
Humidity
Handling

40. Kendall/Hunt Publishing Company
This "identification" was effected by an IAI Certified Latent Print
Examiner employed by a small American police department in the
Midwest.  The examiner had a four year college degree and passed
the IAI CLPE certification exam.  The Examiner's certification was
revoked by the IAI Latent Print Certification Board because
of this erroneous identification. 
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Other Prints
Ears—shape, length and width
Voice—electronic pulses measured on a spectrograph
Foot—size of foot and toes; friction ridges on the foot
Shoes—can be compared and identified by type of shoe, brand, size, year of purchase, and wear pattern.
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Other Prints
Palm—friction ridges can be identified and may be used against suspects.
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Other Prints
Footprints are taken at birth as a means of identification of infants.
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Other Prints
Lips—display several common patterns
Short vertical lines
Short horizontal lines
Crosshatching
Branching grooves
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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 in the eye may be unique to individuals. They are used today for various security purposes.
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47. Kendall/Hunt Publishing Company
AFIS
The Automated Fingerprint Identification System - a computer system for storing and retrieving fingerprints
Began in the early 1970’s 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 1990’s most large jurisdictions had their own system in place. The problem - a person’s fingerprints may be in one AFIS but not in others
IAFIS—the FBI’s Integrated Automated Fingerprint Identification system which is a national database of all 10-print cards from all over the country
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AIFIS
AIFIS VIDEO
How to Compare Fingerprints
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49. Montgomery County AFIS
Automated Fingerprint Identification System (AFIS)
The search is sent via modem to the Department of Public Safety database in Austin, Texas.  A single fingerprint developed from a crime scene can be searched through the entire database at the state level and a positive identification established. 
Tied to AFIS is Live Scan, a computer system that scans the fingerprints of prisoners instead of having to use the traditional ink and paper.  Once the prisoner's fingerprints are scanned, the Live Scan system will automatically transmit the fingerprints, along with other descriptive data, to the Department of Public Safety in Austin. 
Live Scan is very useful for positively identifying prisoners who either refuse to divulge their identity or give a fictitious name. 
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50. History in the U. S.
2010 IAFIS
Integrated Automatic Fingerprint Identification System
Electronic database operated by the FBI
Containing the fingerprints and corresponding criminal histories for more than 55 million subjects
Inquiring agencies get responses to submissions within 2 to 24 hours
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51. New Technology in Prints
Are Faces the New Fingerprints?
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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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53. Kendall/Hunt Publishing Company
More about Prints
For additional information about prints and crime, check out Court TV’s Crime Library
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