FingerprintFingerprintss

The Study of Fingerprints: Dactyloscopy

What was used before What was used before f’prints? f’prints? • Alphonse Bertillion (1883)Alphonse Bertillion (1883)

– French policemanFrench policeman– Detailed description of the suspectDetailed description of the suspect– AnthropometryAnthropometry– 11 measurements11 measurements

• HeightHeight• Expanse of his armsExpanse of his arms• Circumference of his head (using calipers)Circumference of his head (using calipers)• Length of right earLength of right ear• Length of left footLength of left foot• Length of selected fingersLength of selected fingers• Size and shape of noseSize and shape of nose• Tilt of foreheadTilt of forehead• Scars and blemishesScars and blemishes

– The possibility that 2 people would The possibility that 2 people would have the same measurements was 1 in have the same measurements was 1 in 4 million4 million• Ex: Will West (1903 – Leavenworth prison)Ex: Will West (1903 – Leavenworth prison)

HistoryHistory• Bertillion system (Bertillion system (BertillonageBertillonage) )

was used for 20 years (used to was used for 20 years (used to successfully ID 800 criminals)successfully ID 800 criminals)

• William Herschel – IndiaWilliam Herschel – India– Required that native sign for Required that native sign for

contracts using an imprint of their contracts using an imprint of their right handright hand

• Henry FauldHenry Fauld– Scottish physicianScottish physician– Published in 1880 – skin ridge Published in 1880 – skin ridge

patterns could be important for the ID patterns could be important for the ID of criminalsof criminals

• Francis Galton – Francis Galton – – 1892 published “Finger Prints”1892 published “Finger Prints”– Discussed the anatomy of prints Discussed the anatomy of prints – Recommended 3 categoriesRecommended 3 categories

• Loops, arches, whorlsLoops, arches, whorls• No 2 fingerprints are alikeNo 2 fingerprints are alike

HistoryHistory• Creation of Classification systemsCreation of Classification systems

– Needed a way of filing 1000’s of Needed a way of filing 1000’s of prints in a logical/searchable prints in a logical/searchable sequencesequence

• 1891 – Dr. Juan Vucetich 1891 – Dr. Juan Vucetich (Argentinean police officer)(Argentinean police officer)– Devised a system that is still used by Devised a system that is still used by

most Spanish speaking countriesmost Spanish speaking countries• 1897 – Sir Edward Richard Henry 1897 – Sir Edward Richard Henry

SystemSystem– Adopted by Scotland Yard and most Adopted by Scotland Yard and most

English speaking countriesEnglish speaking countries• In the US – 1901In the US – 1901

– Officially adopted for applicants for Officially adopted for applicants for the NYC Civil Serve Commissionthe NYC Civil Serve Commission

HistoryHistory• In the US (cont.)In the US (cont.)• 1924 – fingerprint records were 1924 – fingerprint records were

combined to form the identification combined to form the identification records of the newly formed FBIrecords of the newly formed FBI– Largest collection of fingerprints in the Largest collection of fingerprints in the

worldworld

• 1999 – 1999 – US v. Byron C. MitchellUS v. Byron C. Mitchell– Eastern PAEastern PA– Defendant claimed that fingerprints Defendant claimed that fingerprints

could not be unique under the could not be unique under the DaubertDaubert rulingruling

– Judge came back with a verdict which Judge came back with a verdict which statedstated• Human friction ridges are unique and Human friction ridges are unique and

permanentpermanent• Human friction ridge skin arrangements are Human friction ridge skin arrangements are

unique and permanentunique and permanent

HistoryHistory• DaubertDaubert

– Whether the scientific technique or Whether the scientific technique or theory can be (and has been) testedtheory can be (and has been) tested

– Whether the technique or theory Whether the technique or theory has been subject to peer review and has been subject to peer review and publicationpublication

– The techniques potential rate of The techniques potential rate of errorerror

– Existence and maintenance of Existence and maintenance of standards controlling the standards controlling the techniques operationtechniques operation

– Whether the scientific theory or Whether the scientific theory or method has attracted widespread method has attracted widespread acceptance within a relevant acceptance within a relevant scientific communityscientific community

Fundamental Fundamental PrinciplesPrinciplesof Fingerprintsof Fingerprints

A fingerprint is an A fingerprint is an

individual characteristic.individual characteristic.

A fingerprint will remain A fingerprint will remain

unchanged during an unchanged during an

individual’s lifetime.individual’s lifetime.

Fingerprints have general Fingerprints have general

characteristic ridge characteristic ridge

patterns that permit them patterns that permit them

to be systematically to be systematically

classified.classified.

Stick to the Stick to the FundamentalsFundamentals• Three (3) Principles of Three (3) Principles of

FingerprintsFingerprints• 11stst – A fingerprint is an – A fingerprint is an

individual characteristic; individual characteristic; – no two fingers have yet been no two fingers have yet been

found to possess identical ridge found to possess identical ridge characteristicscharacteristics

– Individuality is determined by Individuality is determined by the number, ID and relative the number, ID and relative location of its location of its ridge ridge characteristicscharacteristics (minutiae) (minutiae)• There are as many as 150 individual There are as many as 150 individual

characteristics on the average characteristics on the average fingerprintfingerprint

Stick to the Stick to the FundamentalsFundamentals• Three (3) Principles of Three (3) Principles of

Fingerprints (cont.)Fingerprints (cont.)•Unfortunately - most prints Unfortunately - most prints

only come in partialsonly come in partials• 1973 – International 1973 – International

Association of IdentificationAssociation of Identification– Concluded, “no valid basis Concluded, “no valid basis

exists for requiring a exists for requiring a predetermined minimum predetermined minimum number of friction ridge number of friction ridge characters which must be characters which must be present in 2 impressions in present in 2 impressions in order to establish positive order to establish positive identification”identification”

Ridge CharacteristicsRidge CharacteristicsMinutiaeMinutiae——characteristics of ridge characteristics of ridge

patternspatterns

Ridge endingRidge ending Short ridgeShort ridge Dot or Dot or

fragmentfragment BifurcationBifurcation Double Double

bifurcationbifurcation TrifurcationTrifurcation BridgeBridge IslandIsland EnclosureEnclosure SpurSpur

Fingerprint MinutiaeFingerprint Minutiae

Three Principles (cont.)Three Principles (cont.)• 22ndnd – A fingerprint will remain – A fingerprint will remain

unchanged during an unchanged during an individual’s lifetimeindividual’s lifetime– Epidermis and DermisEpidermis and Dermis– Fingerprints are a reproduction Fingerprints are a reproduction

of skin ridges (used for of skin ridges (used for friction/firmer grasps)friction/firmer grasps)

– Dermal papillae – boundary Dermal papillae – boundary between the dermis/epidermisbetween the dermis/epidermis•Determine the form and pattern Determine the form and pattern

of the ridges on the surface of of the ridges on the surface of the skinthe skin

•Develop in the fetusDevelop in the fetus

Three Principles (cont.)Three Principles (cont.)• Each skin ridge has a single Each skin ridge has a single

row of poresrow of pores– openings for ducts leading openings for ducts leading

form the sweat glands form the sweat glands (perspiration)(perspiration)•Oils come for other parts of the Oils come for other parts of the

body (no oil glands on hand/feet)body (no oil glands on hand/feet)– Both the sweat and oil can lead Both the sweat and oil can lead

to…to…

• Latent fingerprintsLatent fingerprints – – – Prints that are invisible to the Prints that are invisible to the

naked eyenaked eye

• Impossible to change one's Impossible to change one's fingerprintsfingerprints– Ex: John DillingerEx: John Dillinger

Epidermal Ridges of Thick SkinEpidermal Ridges of Thick Skin

Three Principles (cont.)Three Principles (cont.)• 33rdrd – Fingerprints have general – Fingerprints have general

ridge patterns that permit them ridge patterns that permit them to be systematically classifiedto be systematically classified

• 3 classes –3 classes –1. loops (60-65%) – ridge lines that 1. loops (60-65%) – ridge lines that

enter from one side of the pattern enter from one side of the pattern and curve around to exit from the and curve around to exit from the same side of the patternsame side of the pattern•Ulnar – opens toward the little fingerUlnar – opens toward the little finger•Radial – opens toward the thumbRadial – opens toward the thumb•Type lines – two diverging lines that Type lines – two diverging lines that

surround the loopsurround the loop•Delta – all loops must have oneDelta – all loops must have one

– The ridge point at or nearest the type line The ridge point at or nearest the type line divergence divergence

– located at or directly in front of the point located at or directly in front of the point of divergenceof divergence

•Core – approximate center of the loopCore – approximate center of the loop

LoopLoop A loop must have one or more ridges A loop must have one or more ridges

entering and exiting from the same side. entering and exiting from the same side. Loops must have one delta.Loops must have one delta.

TypesTypes RadialRadial——opens toward the thumbopens toward the thumb UlnarUlnar——opens toward the “pinky” (little opens toward the “pinky” (little

finger)finger) Which type of loop is this, if it is on the Which type of loop is this, if it is on the

right hand? Left hand?right hand? Left hand?

Three Classes (cont.)Three Classes (cont.)2. whorls (30-35%) – ridge patterns 2. whorls (30-35%) – ridge patterns

that are generally rounded or that are generally rounded or circular in shape…must have:circular in shape…must have:– type lines and at least 2 deltastype lines and at least 2 deltas– At least one ridge that makes a At least one ridge that makes a

complete circuitcomplete circuit– Spiral, oval or any variant of a Spiral, oval or any variant of a

circlecircle– 4 types:4 types:

•plain whorlplain whorl– If you can draw an imaginary line between If you can draw an imaginary line between

the 2 deltas contained within these 2 the 2 deltas contained within these 2 patterns…and have the line touch any one of patterns…and have the line touch any one of the spiral edgesthe spiral edges

•pocket looppocket loop– If no such edge is touched the pattern is a If no such edge is touched the pattern is a

centralcentral

WhorlWhorl

WhorlWhorl

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

TypesTypes PlainPlain Central PocketCentral Pocket Double LoopDouble Loop AccidentalAccidental

Three Principles (cont.)Three Principles (cont.)•Whorls (cont.)Whorls (cont.)– Double loop – 2 loops Double loop – 2 loops

combined into one combined into one fingerprintfingerprint

– Accidental – Accidental – •contains 2 or more patterns contains 2 or more patterns (not including the plain arch)(not including the plain arch)

•Pattern not covered by other Pattern not covered by other categoriescategories

Three Classes (cont.)Three Classes (cont.)• Arch (5%) – ridge lines that Arch (5%) – ridge lines that

enter the print from one side enter the print from one side and flow out the other sideand flow out the other side– Do not have type lines, deltas or Do not have type lines, deltas or

corescores– Least commonLeast common– Plain arch – Plain arch – simplest of allsimplest of all

•See definition aboveSee definition above• Form a wavelike patternForm a wavelike pattern

– Tented arch Tented arch • Instead of rising smoothly at the Instead of rising smoothly at the

center there's acenter there's a sharp spike or the sharp spike or the ridges meet at an angle that is less ridges meet at an angle that is less than 90 degreesthan 90 degrees

ArchArch

An arch has friction ridges that enter An arch has friction ridges that enter on one side of the finger and cross to on one side of the finger and cross to the other side while rising upward in the other side while rising upward in the middle. They do NOT have type the middle. They do NOT have type

lines, deltas, or cores.lines, deltas, or cores. TypesTypes

PlainPlain TentedTented

Classification of PrintsClassification of Prints•Original Henry systemOriginal Henry system•FBI SystemFBI System–Primary ClassificationPrimary Classification•All the fingerprint cards All the fingerprint cards in the world can be in the world can be divided into 1,024 groupsdivided into 1,024 groups

•Pair up fingersPair up fingers

Classification of Prints Classification of Prints (cont.)(cont.)• FBI System (cont.)FBI System (cont.)R. IndexR. Index R. RingR. Ring L. ThumbL. Thumb L. MiddleL. Middle L. L.

LittleLittleR. Thumb R. Middle R. Little L. Index L. R. Thumb R. Middle R. Little L. Index L.

RingRing

– Based on the Based on the presence/absence of a whorl presence/absence of a whorl pattern and then assigned a pattern and then assigned a specific valuespecific value•first pair - 16first pair - 16•Second pair – 8Second pair – 8•Third pair – 4Third pair – 4•Fourth pair – 2Fourth pair – 2•Last/fifth pair – Last/fifth pair – 11 (one) (one)

– Finger with an arch or loop Finger with an arch or loop pattern is assigned a zero (0)pattern is assigned a zero (0)

Classification of Prints Classification of Prints (cont.)(cont.)• FBI System (cont.)FBI System (cont.)R. IndexR. Index R. RingR. Ring L. ThumbL. Thumb L. MiddleL. Middle L. L.

LittleLittle

R. Thumb R. Middle R. Little L. Index L. R. Thumb R. Middle R. Little L. Index L. RingRing

– After values are taken for all After values are taken for all 10 fingers….they are totaled 10 fingers….they are totaled and and 11 (one) is added to the (one) is added to the numerator and the numerator and the denominatordenominator

– The resulting fraction is the The resulting fraction is the primary classificationprimary classification

– 25% of the population falls into 25% of the population falls into the the 1/1 1/1 category (all their category (all their fingers have loops or arches)fingers have loops or arches)

AFISAFIS• Automated Fingerprint Automated Fingerprint

Identification SystemsIdentification Systems– A computer scans and digitally A computer scans and digitally

encodes fingerprints so they can be encodes fingerprints so they can be subject to high speed computer subject to high speed computer processingprocessing

– determines the relative position determines the relative position and orientation of the minutiaeand orientation of the minutiae

– ““Uses automatic scanning devices Uses automatic scanning devices that convert the image of a that convert the image of a fingerprints into digital minutiae fingerprints into digital minutiae that contain data showing ridges at that contain data showing ridges at their point of termination (?) and their point of termination (?) and the branching of ridges into 2 the branching of ridges into 2 ridges (?)”ridges (?)”

– Makes no final decisions…that is Makes no final decisions…that is left up the fingerprint expertleft up the fingerprint expert

Kinds of Crime Scene Kinds of Crime Scene PrintsPrints•Visible prints – Visible prints –

– made by fingers touching a made by fingers touching a surface after ridges have surface after ridges have been in contact with a colored been in contact with a colored materials (blood, paint, etc.)materials (blood, paint, etc.)

•Plastic Prints – Plastic Prints – – ridge impressions left on a ridge impressions left on a

soft material (putty, wax, soft material (putty, wax, soap or dust)soap or dust)

• Latent/invisible prints – Latent/invisible prints – – caused by the transfer of caused by the transfer of

perspiration/oils on finger perspiration/oils on finger ridges to the surface of an ridges to the surface of an objectobject

Methods of DetectionMethods of Detection•Method of choice Method of choice

depends on the type of depends on the type of printprint

•Hard/non-absorbent Hard/non-absorbent surfaces require different surfaces require different methods than soft/porous methods than soft/porous materialsmaterials– Powders and Super Glue ® Powders and Super Glue ®

vs. chemical treatmentsvs. chemical treatments

•Most difficult aspect of Most difficult aspect of fingerprint examination?fingerprint examination?

Methods (cont.)Methods (cont.)•VisualizationVisualization– RUVIS (Reflected Ultraviolet RUVIS (Reflected Ultraviolet

Imaging System)Imaging System)•Locates prints on most Locates prints on most nonabsorbent surfaces nonabsorbent surfaces without chemical or powderswithout chemical or powders

•UV light strikes the UV light strikes the fingerprints, is reflected back fingerprints, is reflected back to the viewer, then converted to the viewer, then converted into visible light into visible light by an image by an image intensifierintensifier

Visualization (cont.)Visualization (cont.)• Fingerprint powdersFingerprint powders– Applied to nonabsorbent Applied to nonabsorbent

surfaces with a camel hair surfaces with a camel hair or fiberglass brushor fiberglass brush•Adheres to oils/perspirationAdheres to oils/perspiration

– Gray and black powders Gray and black powders are are adequate for most latent adequate for most latent print workprint work

– Magnetic sensitive powderMagnetic sensitive powder•Useful for leather and rough Useful for leather and rough plasticsplastics

– Fluorescent powdersFluorescent powders

Visualization (cont.)Visualization (cont.)• Iodine fuming Iodine fuming (hardly used anymore)(hardly used anymore)

– Heat iodine crystals Heat iodine crystals vapor without vapor without passing thru a liquid phase (?)passing thru a liquid phase (?)

– How does it work?How does it work?• Put suspect material in a cabinet with the Put suspect material in a cabinet with the

heated iodine crystalsheated iodine crystals• Vapors fill the chamber and combine with Vapors fill the chamber and combine with

constituents of the latent print to make it constituents of the latent print to make it visiblevisible

• Reason? Reason? – No one knows for sureNo one knows for sure– fatty oils or residual water left on a print fatty oils or residual water left on a print

from perspirationfrom perspiration• ProblemsProblems

– Not permanent -- fades once fuming is Not permanent -- fades once fuming is stoppedstopped

• ThereforeTherefore??– Must be photographed immediatelyMust be photographed immediately– Or fixed with a 1% starch-water solution Or fixed with a 1% starch-water solution

that is sprayed onthat is sprayed on» The print will then turn blue and last weeks-The print will then turn blue and last weeks-

monthsmonths

Visualization (cont.)Visualization (cont.)• Ninhydrin Ninhydrin (another chemical)(another chemical)

– Method of choice for most examinersMethod of choice for most examiners• Extremely sensitive and easy to Extremely sensitive and easy to

apply/useapply/use

– Forms a Forms a purple-blue purple-blue color with amino color with amino acids present in perspirationacids present in perspiration

– Commonly sprayed on to porous Commonly sprayed on to porous surfacessurfaces

– Prints begin to appear in an hour or 2 Prints begin to appear in an hour or 2 – Development can be hastened if the Development can be hastened if the

treated specimen is heated in an treated specimen is heated in an oven or hotplate at 80-100oven or hotplate at 80-100ooCC

– Has been used on papers as old as 15 Has been used on papers as old as 15 yearsyears

Visualization (cont.)Visualization (cont.)•Physical Developer Physical Developer (yet (yet

another chemical)another chemical)– Silver nitrate-based liquid Silver nitrate-based liquid

reagentreagent– Useful for turning up prints Useful for turning up prints

on porous surfaces that had on porous surfaces that had been wetbeen wet

– Problem?Problem?•PD washes away any trace of PD washes away any trace of protein that may be on/a part protein that may be on/a part of the print/surfaceof the print/surface

Visualization (cont.)Visualization (cont.)• Super Glue ® FumingSuper Glue ® Fuming

– 19821982– Good for detection on nonporous Good for detection on nonporous

surfaces such as metal, electrical surfaces such as metal, electrical tape, leather and plastic bagstape, leather and plastic bags

– Fumes can be created when the Fumes can be created when the glue is placed on cotton treated glue is placed on cotton treated with NaOH with NaOH (as well as heating the (as well as heating the glue)glue)

– Put in an enclosed chamber for Put in an enclosed chamber for approx. 6 hours and the fumes approx. 6 hours and the fumes from the glue will adhere to the from the glue will adhere to the latent printlatent print•Gives the print a white-appearanceGives the print a white-appearance

– Now have hand held wands that do Now have hand held wands that do the same thing…can direct the the same thing…can direct the fumes to particular places (ex: car, fumes to particular places (ex: car, etc.)etc.)

Visualization (cont.)Visualization (cont.)• FluorescenceFluorescence

– Def: when a substance absorbs Def: when a substance absorbs light and reemits the light in light and reemits the light in wavelengths longer than the wavelengths longer than the illumination sourceillumination source

– Laser lightLaser light•Perspiration contains a variety of Perspiration contains a variety of

components that fluoresce when components that fluoresce when exposed to lasersexposed to lasers

•Drawback? Drawback? – Only small amounts of perspiration Only small amounts of perspiration

components are present in the fingerprintcomponents are present in the fingerprint

• The examiner wears safety goggles The examiner wears safety goggles containing optical filterscontaining optical filters– The goggles will absorb some of the light, The goggles will absorb some of the light,

but let the wavelengths at which prints but let the wavelengths at which prints fluoresce pass thrufluoresce pass thru

Visualization (cont.)Visualization (cont.)• Fluorescence and lasers Fluorescence and lasers

(cont.)(cont.)– Treat fingerprints with chemicals Treat fingerprints with chemicals

that bring about fluorescence that bring about fluorescence when exposed to laserswhen exposed to lasers

– Apply:Apply:•zinc chloride after ninhydrin zinc chloride after ninhydrin treatment treatment

•dye rhodamine 6G after Super Glue dye rhodamine 6G after Super Glue fumingfuming

Visualization (cont.)Visualization (cont.)•Alternate Light SourceAlternate Light Source– Because of chemically induced Because of chemically induced

fluorescence, lasers no longer fluorescence, lasers no longer neededneeded

– High intensity lights are High intensity lights are sufficientsufficient•Quartz halogen, xenon arc or Quartz halogen, xenon arc or indium can be focused in a suspect indium can be focused in a suspect areas thru a fiber optic cableareas thru a fiber optic cable

•Can be passed thru a number of Can be passed thru a number of filtersfilters– more flexibility as to the wavelength more flexibility as to the wavelength

of light to be aimed at the printof light to be aimed at the print

– Cheaper and more portableCheaper and more portable

Visualization (cont.)Visualization (cont.)•Common fingerprint agents Common fingerprint agents

do not interfere with DNA do not interfere with DNA testing methodstesting methods

•Recommended that in cases Recommended that in cases involving items with material involving items with material adhering to surfaces that adhering to surfaces that will require further lab will require further lab exams, fingerprint exams, fingerprint processing should not be processing should not be performed at the crime performed at the crime scenescene

Preservation of Preservation of Developed PrintsDeveloped Prints• For future comparisonFor future comparison– Take a picture…Take a picture…it’ll last longerit’ll last longer

• If the object on which the print is If the object on which the print is located is small enough to located is small enough to move/transport…take it wichyamove/transport…take it wichya– Cover it in cellophaneCover it in cellophane

• If the print is a part of an object is If the print is a part of an object is too large to move, it can be liftedtoo large to move, it can be lifted– Preserve the print with powderPreserve the print with powder– Apply broad adhesive tape onto the Apply broad adhesive tape onto the

print (evenly)print (evenly)– Place the tape/print on a properly Place the tape/print on a properly

labeled card that shows contrastlabeled card that shows contrast– Also able to be used: adhesive-backed Also able to be used: adhesive-backed

clear plastic sheet that is attached to clear plastic sheet that is attached to a colored cardboard backinga colored cardboard backing