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Chapter 4: Fingerprints

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Page 1: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Chapter 4: Fingerprints

Page 2: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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History• First fingerprints were discovered in

clay pottery during the T’ang Dynasty

• Dactyloscopy: study of fingerprints

Page 3: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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History• Alphonse Bertillion

– First systematic attempt at personal identification

Bertillion system– Relied on a detailed description of the

subject– Combined with full length and profile

photographs– System of precise body

measurements called anthropometry

Page 4: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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History

• Francis Galton– 1892– Classic textbook finger prints

• At Galton’s insistence– British government adopted fingerprinting– Supplement to the bertillion system.

• Next step– Creation of classification systems– Capable of filing many thousands of prints– Logical and searchable sequence.

Page 5: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

WHY FINGERPRINTS?WHY FINGERPRINTS?• The most positive means for

identifying people.

• Because no two fingers with identical ridge characteristics

• The most positive means for identifying people.

• Because no two fingers with identical ridge characteristics

• Fingerprints form on a person before birth and remain unchanged until the body decomposes after death.

• Fingerprints form on a person before birth and remain unchanged until the body decomposes after death.

Every fingerprint is unique!Every fingerprint is unique!

Page 6: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

WHAT IS A FINGERPRINT?WHAT IS A FINGERPRINT?

A fingerprint is a pattern comprised of ridges and valleys.

A Ridge – is a high.

A Valley – is a depression or low.

A fingerprint is a pattern comprised of ridges and valleys.

A Ridge – is a high.

A Valley – is a depression or low.

Friction ridges are also found on our palms, feet and toes.Friction ridges are also found on our palms, feet and toes.

Page 7: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

RidgeRidgeValleyValley

Page 8: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Fingerprint Principles• Individual characteristic

–Because no two fingers with identical ridge characteristics

• Remains unchanged during an individual’s lifetime

• General ridge patterns that permit systematic classification

Page 9: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Anatomy of Fingerprints• Epidermis

– Outer layer of the skin• Dermis

– Inner layer of the skin• Dermal papillae

– Layer of cells between the epidermis and dermis

– Responsible for determining the form and pattern of the ridges on the surface of the skin

Page 10: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Anatomy of fingerprints• Dermal papillae

develop in the human fetus @ 3 months

• Enlarge during growth

Page 11: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Anatomy of fingerprints

• Finger touches a surface–Perspiration–Oils from hairy portions of the body

–Transferred onto surface• Leaves fingerprint

Page 12: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Fingerprint patterns• All fingerprints

– divided into three classes – Loops– Arches– whorls L.A.W.

Page 13: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Loops

• A loop must have one or more ridges entering from one side of the print, re-curving, and exiting from the same side.

– If the loop opens toward the little finger, it is called an ulnar loop.

– If the loop opens toward the thumb, it is called a radial loop.

Page 14: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Figure4.3  Loop pattern.

Loops

Page 15: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Loops• Must have one

delta

Page 16: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Whorls

Page 17: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Whorls• Divided into four groups

–Plain–Central pocket loop–Double loop–Accidental

• All have a minimum of two deltas

Page 18: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Whorls• Plain whorl and central pocket loop have

at least one ridge that makes a complete circuit

• Double loop: two loops combined into one fingerprint

• Accidental– Two or more patterns– Or pattern not covered by the other

categories

Page 19: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Arches

Page 20: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Arches• Least common of general

patterns–Plain arches–Tented arches

–Arches do not have deltas, or cores

Page 21: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Plain Arches• Ridges entering from one side of the

print• Rising and falling• Exiting on the opposite side• Like a wave

Page 22: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Tented Arches• Sharp up-thrust or

spike

• The ridges meet at an angle that is less than 90 degrees

Page 23: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Questions???

Page 24: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

How are fingerprints compared?How are fingerprints compared?

A. Fingerprints are compared by noting the ridge characteristics on two prints to determine whether or not they match.

B. An identification is established when a number of these characteristics occupy the same relative position on the two prints.

A. Fingerprints are compared by noting the ridge characteristics on two prints to determine whether or not they match.

B. An identification is established when a number of these characteristics occupy the same relative position on the two prints.

FINGERPRINT IDENTIFICATIONFINGERPRINT IDENTIFICATION

Page 25: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Fingerprints and a fingerprint classification schema involving six categories: (a) arch, (b) tented arch, (c) right loop, (d) left loop, (e) whorl, and

(f) double loop. Critical points in a fingerprint,called core and delta, are marked as squares and triangles.

Page 26: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

FINGERPRINT IDENTIFICATIONFINGERPRINT IDENTIFICATION

Henry Classification system• Developed a method of classifying fingerprints. • modified by the FBI that allowed all set of 10

fingerprints in the world to be divided into 1024 groups.

Table 4.2 Frequency of fingerprints Loops WhorlsArchesUlnar radial plain other plain tented60% 5% 20% 10% 4% 1% loops = 65% whorl=30% arches =5%

Henry Classification system• Developed a method of classifying fingerprints. • modified by the FBI that allowed all set of 10

fingerprints in the world to be divided into 1024 groups.

Table 4.2 Frequency of fingerprints Loops WhorlsArchesUlnar radial plain other plain tented60% 5% 20% 10% 4% 1% loops = 65% whorl=30% arches =5%

Page 27: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

RIDGE CHARACTERISTICS (Minutiae) RIDGE CHARACTERISTICS (Minutiae)

COMMONCOMMON OCCASIONALOCCASIONAL RARERARE

Ending RidgeEnding Ridge

Bifurcation or fork

Bifurcation or fork

DotDot

Eye or EnclosureEye or Enclosure

“T” Junction“T” Junction

Short RidgeShort Ridge

TrifurcationTrifurcation

Ridge CrossingRidge Crossing

Row of DotsRow of Dots

Page 28: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Rid

ge C

har

acte

rist

ics

Use these characteristics as points of identification when comparing fingerprint samples. The more points you can find in common, the better the match!

Page 29: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints
Page 30: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

RIDGE CHARACTERISTICS MAGNIFIEDRIDGE CHARACTERISTICS MAGNIFIED

Points 1, 2, 4, 5 are Ending RidgesPoints 1, 2, 4, 5 are Ending Ridges

Points 8, 10, 11 are BifurcationsPoints 8, 10, 11 are Bifurcations

Point 7 Short RidgePoint 7 Short Ridge

Points 3 and 9 are DotsPoints 3 and 9 are Dots

Point 6 is an Enclosure (ISLAND)Point 6 is an Enclosure (ISLAND)

11

22

44

55

88

10101111

99

77

33

66

Page 31: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints
Page 32: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Review of fingerprint types

Page 33: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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 Arches Similar to the plain arch,

but has a spike in the center.

Spike or “tent”

Page 34: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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.

Delta

Ulnar Loop (Right Thumb)

Loop opens toward right or the ulna bone.

Radial Loop (Right Thumb)

Loop opens toward the left or the radial bone.

NOTE: On the left hand, a loop that opens to the left would be an ulnar loop, while one that opens to the right would be a radial loop.

Page 35: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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 Whorl

Central Pocket Whorl

Page 36: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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

Page 37: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Identify each fingerprint pattern.

?A B

CD ERight

Hand

Left Hand

Left Hand

Right Hand

Right Hand

Page 38: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Presenting Fingerprints as Evidence

• No legal requirements on the number of points but generally the courts will accept 8 to 12 points of similarity as sufficient proof.

• Fingerprints do not lie but human error might account to wrongful convictions.

Page 39: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Types of PrintsVisible & Latent Prints

Page 40: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Latent Prints• Invisible fingerprints

• Finger touches a surface

• Body perspiration and/or oils present

• Transferred to that surface

• Leaves impression

Page 41: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Visible Prints• Fingers touch a surface after contact with

a colored material such as blood, paint, grease, or ink

• Plastic prints: left on a soft material, such as putty, wax, soap, or dust

• Little problem to the investigator

Page 42: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Visualizing Latent Prints

Page 43: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Detecting Prints• Hard nonabsorbent surfaces

–Glass, mirror, tile, painted wood–Developed by the application of a

powder–Can be lifted by clear tape &

examined

• Porous surfaces–Papers, cardboard, and cloth,

styrofoam, leather–Require treatment with a chemical

Page 44: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Ninhydrin• Reacts with amino acids left by

finger• Produces a orange /purple

color (Ruhemann’s purple)• Commonly used with paper

and porous surfaces

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Page 45: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Iodine Fuming• Heat iodine crystals (produces iodine

vapors)

• Combine with latent prints (react w/ oils on finger) to make them visible– Iodine prints are not permanent– Will fade– Must photograph the prints immediately– Works best on porous paper.

Page 46: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Silver nitrate• Reacts with the salt left from

sweat in a dried print .

• AgNO3 + NaCl AgCl *converts to dark Ag2O

• Turns prints brownish-purple

Page 47: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Super Glue®

• Most widely used method to develop latent prints

• Best used on nonporous surfaces such as metals, glass, adhesive tapes and plastic.

• Leaves a white, permanent impression • can be treated with powders or fluorescent

dyes to create a sharper contrast.

• 98 to 99 percent cyanoacrylate ester

Super Glue fuming– Fuming chamber (for up to six hours)

Page 48: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Reflected UV Imaging System• RUlVIS• No chemicals or powder• Locate With light source• investigator develops the print in

the most appropriate fashion

Page 49: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

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Powders

• Powders, available in a variety of colors, can be applied with a brush or magnetic wand, and adhere to perspiration and/or body oils of the print.

Page 50: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Other methods

• Photograph

Page 51: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Digital Imaging- AFIS

• Digital image: of fingers are pressed against a glass plate and scanned to a screen.

** can be enhanced, compared and sent to AFIS within minutes. AFIS can compare hundreds of thousands of prints in less than a second.

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Page 52: Chapter 4: Fingerprints. 2 History First fingerprints were discovered in clay pottery during the T’ang Dynasty Dactyloscopy: study of fingerprints

Digital Imagining: IAFIS

• Replaced tradition method of fingerprinting.• Contains more than 55 million computerized

fingerprint records of known criminals.• Live Scan electronic fingerprints devices

transmit prints @ the time of arrest or booking to a central IAFIS database to provide immediate positive identification, check for with any suspect latent prints on file, and provide criminal history.