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FINGERPRINTS. Chapter 14. Students Will Be Able To:. Describe the formation of a fingerprint. Discuss the history of fingerprinting. “ Today the fingerprint is the pillar of modern criminal identification .”. Dactylscopy. Is the study of fingerprints. Principles of Fingerprints. - PowerPoint PPT Presentation
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FINGERPRINTS
1
Chapter 14
Students Will Be Able To:
• Describe the formation of a fingerprint.• Discuss the history of fingerprinting.
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“Today the fingerprint is the pillar of modern criminal identification.”
Dactylscopy
• Is the study of fingerprints
Principles of Fingerprints
• Is an individual characteristic• Will remain unchanged during an
individual’s lifetime• Have general characteristic ridge
patterns that permit them to be classified
History of Fingerprinting
• Earliest records of using fingerprints date back to 1792-1750 BC in Babylon• Used to bind contracts
• In China, fingerprints were used on contracts and loans
• In 1788 Johann Christoph Andreas Mayer stated that no two people had the same ridge pattern
• In 1823, Jan Purkyn described 9 distinct fingerprint patterns• Loops• Spirals• Circles• Double whorls
The History of Fingerprinting
• Throughout history, there are six significant people involved in fingerprinting• William Herschel• Henry Faulds• Alphonse Bertillion• Francis Galton• Edward Richard Henry• Juan Vucetich
William Herschel
• Began collecting fingerprints in 1856• Said that patterns were unique to each
person and were not altered by age• Required natives to sign contracts with
imprint of right hand
Henry Faulds
• Suggested that skin ridge patterns could be important for the identification of criminals
Alphonse Bertillion
• Proposed body measurements as a means of identification• Field called anthropometry
• System called for 11 measurements to be taken• Height, reach, width of head, length of
each food are a few examples• Identification via anthropometry was
replaced with fingerprints• No two people can have the same
fingerprints; however, 2 people can have the same anthropometric measurements
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Francis Galton
• Verified that fingerprints do not change with age
• Developed a primary classification scheme based on loops, whorls, and arches
• Wrote a book called Finger Prints• States that a person’s fingerprints do
not change over the years• His system was adopted by the British
government• Was the first person credited with solving a
murder using fingerprints
Edward Richard Henry
• Worked with Galton to institute a numerical classification system to file fingerprints
• English speaking countries including the US use Henry’s classification system
• Also Devised the ten print card• All fingers are
fingerprinted
Juan Vucetich
• Developed a fingerprint classification based on Galton’s that is used in Spanish speaking countries
History Clip
Fingerprints
• Fingerprints are a reproduction of friction skin ridges found on the palm side of the fingers and thumbs• Also found on the surface of the palms
and the soles of the feet• Provide our bodies with a firm grasp and
resistance to slippage
Fingerprints
• Form in utero beginning at the 10th week of pregnancy
• Creation happens in the basal layer of the epidermis• Skin cells grow more rapidly here than
the epidermis on the outside and the dermis on the inside
• Basal layer ends up collapsing and folding in different directions
Skin
• Is composed of layers of cells• 2 main portions exist
• Epidermis• Outer portion of the skin
• Dermis • Inner portion of the skin
• Dermal papillae separate the 2 portions• Shape of the boundary determines the
form and pattern of the ridges
Skin
• Each skin ridge has a row of pores • Are openings for ducts leading from the
sweat gland• Perspiration and oils pass through
these ducts• Is left behind when an object has
been touched• This is the fingerprint
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Where Do Fingerprints Come From Video Clip
Students Will Be Able To:
• Describe the characteristics of fingerprints.• Identify the basic types of fingerprints.
Characteristics of Fingerprints
• Two things a forensic examiner look for on a fingerprint are• Presence of a core
• Is the center of the loop or whorl• Presence of a delta
• Is a triangular region located near a loop
• Also use a ridge count• Is the area from the delta to the core
Pattern Characteristics
• All fingerprints are divided into three classes based on their pattern• Loops• Whorls• Arches
Loops
• Must have one or more ridges entering and exiting from the same side
• Must have one delta• 2 types
• Radial- opens toward the thumb• Ulnar- opens toward the pinky
• Occurs in 60-65% of the population
LoopsLoops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones.
DeltaUlnar Loop (Right Hand)
Loop opens toward the little finger (or ulna).
Radial Loop (Right Hand)Loop opens toward the thumb (or radius).
Delta
Whorls
• Must have a type line, a core, and a minimum of 2 deltas
• Divided into 4 groups• Plain- have at least one ridge that
makes a complete circuit• Central pocket loop- have at least one
ridge that makes a complete circuit• Double loop- made up of 2 loops
combined into one fingerprint• Accidental- contains 2 or more patterns
or is a pattern covered by the other categories
• Occur in 30-35% of the population
WhorlsWhorls have at least one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas. If a print has more than two deltas, it is most likely an accidental.
Draw a line between the two deltas in the plain and central pocket whorls. If some of the curved ridges touch the line, it is a plain whorl. If none of the center core touches the line, it is a central pocket whorl.
Plain WhorlCentral Pocket Whorl
Whorls – Part 2
Accidental Whorl
Accidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories.
Double Loop Whorl
Double loop whorls are made up of any two loops combined into one print.
Delta
Delta
Arches
• Has friction ridges that enter on one side of the finger and cross to the other side while rising upward in the middle
• Do not have type lines, deltas, or cores
• 2 types• Plain- normal wavelike pattern• Tented- is the same as plain except that
a sharp spike occurs at the center• Occur in 5% of the population
ArchesArches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present.
Plain ArchRidges enter on one side and
exit on the other side.
Tented ArchesSimilar to the plain arch,
but has a spike in the center.
Spike or “tent”
Your Turn
Ridge Characteristics
• Must match in two fingerprints in order for their common origin to be established
• No set limit on how many minutiae must match has been set• However, courts
will accept 8-12 points of similarity
• Also known as minutiae
• Includes• Ridge ending• Short ridge• Dot or fragment• Bifurcation• Double bifurcation• Trifurcation• Bridge• Island• Enclosure• Spur
Students Will Be Able To:
• Identify the importance of the Henry classification system for fingerprints.
• Calculate the classification number of an individual with certain whorl patterns.
Primary Classification
• The Henry- FBI classification system
Primary Classification
• It will provide the fingerprint examiner with a number of candidates
• System is only useful in cases when a full set of fingerprints is available
Primary Classification
• Each finger is assigned a number of points if a whorl is present
right right left left left index ring thumb middle little + 1
right right right left left thumb middle little index ring +1
=
Primary Classification• The lowest primary classification a person can have is
1/1
0 + 0 + 0 + 0 + 0 + 1 = 1
0 + 0 + 0 + 0 + 0 + 1 1
If an individual has the lowest possible classification, you would immediately know that the person has loops or arches on all ten fingers and no whorls
• The highest possible classification a person can have is 32/32
16 + 8 + 4 + 2 + 1 + 1 = 32
16 + 8 + 4 + 2 + 1 + 1 32
If an individual has the highest possible classification, you would immediately know that the person has whorls on all ten fingers
Students Will Be Able To:
• Distinguish among visible, plastic, and latent fingerprints.
• Explain how fingerprint evidence is collected.
• List the techniques for developing latent fingerprints on porous and nonporous objects.
• Describe the proper procedures for preserving a developed latent fingerprint.
Types of Prints
• 3 types• Visible • Plastic • Latent
Visible Prints
• Prints made when fingers touch a surface after the ridges have been in contact with a colored material such as blood, paint, grease, or ink
Plastic Prints
• Prints made by ridge impressions left on a soft material such as putty, wax, soap, or dust
Latent Prints
• Prints that are not visible to the naked eye• Consist of the natural secretions of human
skin and require development for them to become visible
• 3 types of secretions• Eccrine- water, inorganic and organic
compounds• Sebaceous- secrete fatty or greasy substances• Apocrine- secrete pheromones and other
organic materials
Developing Prints
• Requires substances that interact with secretions that cause the print to stand out against its background
• May be necessary to attempt more than one technique• Start with the least destructive method
Developing Prints
• 5 ways to develop• Powders• Iodine• Ninhydrin• Silver nitrate• Cyanoacrylate
Powders
• Adhere to water and fatty deposits• Color dependent on background
• White or gray for dark surfaces• Black for light surfaces
Iodine Fuming
• Involves heating iodine crystals that cause vapors which combine with latent prints to make them visible
• Prints are not permanent and will fade• Necessary to photograph the prints
Ninhydrin
• Reacts chemically with trace amounts of amino acids present in latent prints to produce a purple- blue color
• Is the preferred method
Silver Nitrate
• Reacts with chloride to form silver chloride, a material which turns gray when exposed to light
Cyanoacrylate
• Is super glue• Fumes react
with water and other fingerprint constituents to form a hard, whitish deposit
Transporting Prints
• If small, preserve entirely • If big, dust and then lift the prints with a
broad adhesive tape• Tape is placed on a properly labeled
card
Behind the Badge- CSU Fingerprints
Students Will Be Able To:
• List and describe the importance of tire prints, shoe prints, lip prints, retinal scans, teeth marks, etc.
• Describe the concept of an automated fingerprint identification system (AFIS) .
Other Prints
• Ears- shape, length, and width• Voice- electronic pulses measured with a
spectrograph
Other Prints
• Shoes • Can be
compared and identified by type of shoe, brand, size, year of purchase, and wear pattern
Other Prints
• Foot• Size of foot and
toes, friction ridges on the foot
Other Prints
• Palm• Friction ridges
can be identified and may be used against suspects
Other Prints
• Lips• Display several
common patterns• Short vertical
lines• Short
horizontal lines• Crosshatching• Branching
grooves
Other Prints
• Teeth• Bite marks are
unique and can be used to identify suspects
Other Prints
• Retinal • Blood vessels
in the eye may be unique to individuals
Other Prints
• Tire prints• Can identify
vehicles
AFIS
• By the 1990s, most large jurisdictions had their own system in place• A problem exists when 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 data of all 10-print cards from all over the country
AFIS
• Stands for Automated Fingerprint Identification System
• Is a computer system for storing and retrieving fingerprints
• Began in the early 1970s 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
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