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Vermont Forensic Vermont Forensic LaboratoryLaboratory
Physical Comparison UnitPhysical Comparison Unit
William William AppelAppelJennifer HannafordJennifer
Hannaford
Al HogueAl HogueRachel Rachel LemeryLemery
27 February 200427 February 2004
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LocardsLocards Exchange PrincipleExchange Principle
It was It was LocardsLocards belief that when a belief that when
a criminal came into contact with an criminal came into contact
with an object or person, a crossobject or person, a
cross--transfer of transfer of evidence occurs.evidence occurs.
-- Richard SafersteinRichard Saferstein11
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LocardsLocards Exchange PrincipleExchange Principle
Wherever he steps, whatever he touches, whatever he Wherever he
steps, whatever he touches, whatever he leaves leaves ---- even
unconsciouslyeven unconsciously---- will serve as silent will serve
as silent evidence against him. Not only his fingerprints or his
evidence against him. Not only his fingerprints or his shoeprints,
but also his hair, the fibers from his clothes, shoeprints, but
also his hair, the fibers from his clothes, the glass he breaks,
the tool mark he leaves, the paint he the glass he breaks, the tool
mark he leaves, the paint he scratches, the blood or semen that he
deposits or scratches, the blood or semen that he deposits or
collects collects ---- all these and more bear mute witness against
all these and more bear mute witness against him. This is evidence
that does not forget. It is not him. This is evidence that does not
forget. It is not confused by the excitement of the moment. It is
not confused by the excitement of the moment. It is not absent
because human witnesses are. absent because human witnesses are. It
is factual It is factual evidenceevidence. Physical evidence cannot
be wrong; it cannot . Physical evidence cannot be wrong; it cannot
perjure itself; it cannot wholly be absent. Only in its perjure
itself; it cannot wholly be absent. Only in its interpretation can
their be error. Only human failure to interpretation can their be
error. Only human failure to find, study, and understand it can
diminish its value.find, study, and understand it can diminish its
value.
-- Paul L. KirkPaul L. Kirk44
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What is Forensic Science?What is Forensic Science? Forensic
Science is the application of science to law.Forensic Science is
the application of science to law.
Forensic science is the application of science to those Forensic
science is the application of science to those criminal and civil
laws that are enforced by police criminal and civil laws that are
enforced by police agencies in a criminal justice systemagencies in
a criminal justice system11
CriminalisticsCriminalistics is concerned with the recognition,
is concerned with the recognition, identification,
individualization and evaluation of physical identification,
individualization and evaluation of physical evidence using the
methods of the natural sciences in evidence using the methods of
the natural sciences in matters of legal significancematters of
legal significance22
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What is a Forensic Scientist?What is a Forensic Scientist?
one who performs investigatory examinations and one who performs
investigatory examinations and laboratory tests to reach a
conclusionlaboratory tests to reach a conclusion33 Crime Scene
InvestigationCrime Scene Investigation Lab AnalysisLab Analysis
a communicator and interpreter of those finding a communicator
and interpreter of those finding he must be able to explain the
methods used to reach he must be able to explain the methods used
to reach those conclusion in a court of law...those conclusion in a
court of law...33 Report Results (oral and/or written)Report
Results (oral and/or written) Court TestimonyCourt Testimony
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What is considered evidence?What is considered evidence?
Bite MarksBite Marks Blood and Body FluidsBlood and Body Fluids
BonesBones Broken Fingernails Broken Fingernails
(striations)(striations) DrugsDrugs ExplosivesExplosives
FiberFiber FingerprintsFingerprints Firearm Powder ResiduesFirearm
Powder Residues Firearms and Tool MarksFirearms and Tool Marks
Glass Hair Ink Paint Petroleum Products Questioned Documents
Shoeprints and Tire Tracks Soil and minerals Teeth Toxicology
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What is NOT forensic What is NOT forensic evidence?evidence?
??
??
??
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The value of evidenceThe value of evidence
Class CharacteristicsClass Characteristics Properties of
evidence that can be only associated with a Properties of evidence
that can be only associated with a
group and never with a single sourcegroup and never with a
single source
Individual CharacteristicsIndividual Characteristics Properties
of evidence that can be attributed to a common Properties of
evidence that can be attributed to a common
source within an extremely high degree of certaintysource within
an extremely high degree of certainty
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Physical Comparison UnitPhysical Comparison Unit
Latent Print ProcessingLatent Print Processing Fingerprint
ComparisonsFingerprint Comparisons Indented WritingIndented Writing
Firearms/Firearms/ToolmarksToolmarks ShoewearShoewear and Tire
Tread Impressionsand Tire Tread Impressions Physical MatchPhysical
Match Forensic PhotographyForensic Photography
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FingerprintsFingerprints
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What is a Fingerprint?What is a Fingerprint?
Friction skin located on the fingers of the palm Friction skin
located on the fingers of the palm side of the hand from the first
joint to the nail side of the hand from the first joint to the nail
bedbed Areas of skin bearing ridges and furrowsAreas of skin
bearing ridges and furrows Corrugated skin on the Corrugated skin
on the volarvolar areas of the skinareas of the skin
Specialized for tractionSpecialized for traction
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Other types of friction skinOther types of friction skin
Palm
Fingers area between first joint and the palm
Feet soles of feet
Toes
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LoopsLoops One or more ridges entering from one side of the
print, One or more ridges entering from one side of the print,
recurvingrecurving, and , and
exiting from the same sideexiting from the same side UlnarUlnar
opens towards the little fingeropens towards the little finger
Radial Radial opens towards the thumbopens towards the thumb
Left Slant Right Slant
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WhorlsWhorls Enters from both sides and ridge flow that is
circular in natureEnters from both sides and ridge flow that is
circular in nature
Divided into four distinct groupsDivided into four distinct
groups
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ArchesArches Ridges that enter on one side and flow or tend to
flow out the oRidges that enter on one side and flow or tend to
flow out the other ther
with a rise in the centerwith a rise in the center Divided into
two distinct groupsDivided into two distinct groups
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Fingerprint Individual CharacteristicsFingerprint Individual
Characteristics
Details within the ridge flow that represent a unique Details
within the ridge flow that represent a unique occurrence occurrence
(type, relative location, orientation and number)(type, relative
location, orientation and number) Ending ridgeEnding ridge
BifurcationBifurcation DotDot
Also known asAlso known as GaltonGalton DetailsDetails
MinutiaeMinutiae Points of ComparisonPoints of Comparison
Random genetic expressionRandom genetic expression
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Ending RidgeEnding RidgeA ridge that follows a distinct path and
ends abruptlyA ridge that follows a distinct path and ends
abruptly
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BifurcationBifurcationRidge that follows a distinct path and
divides into two ridgesRidge that follows a distinct path and
divides into two ridges
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DotDotA ridge unit that is as long as it is wideA ridge unit
that is as long as it is wide
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Scientific BasisScientific Basis
Fingerprints can be used for individualization Fingerprints can
be used for individualization because they are because they are
UniqueUnique PermanentPermanent
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UniquenessUniqueness
No two individuals or two fingers from the No two individuals or
two fingers from the same hand share the exact friction ridge same
hand share the exact friction ridge detaildetail
In over 100 years of billions of friction ridge In over 100
years of billions of friction ridge comparisons, no one has yet to
find two areas of comparisons, no one has yet to find two areas of
friction skin from different sources with the same friction skin
from different sources with the same ridge configurationridge
configuration
Identical twins Identical twins Same genetic makeSame genetic
make--upup How would this manifest itself in fingerprints?How would
this manifest itself in fingerprints?
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PermanencePermanence
During fetal development, friction ridges are During fetal
development, friction ridges are formed and are permanent
throughout life formed and are permanent throughout life until
death and decompositionuntil death and decomposition
Except in instances of permanent scarring or Except in instances
of permanent scarring or amputationamputation
Are these unique characteristics?Are these unique
characteristics?
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Latent PrintsLatent Prints
Generic term used to describe Generic term used to describe
ANYANY evidentiary print evidentiary print recovered from a crime
scenerecovered from a crime scene
The The unintentionalunintentional recording of friction ridge
skinrecording of friction ridge skin
A reproduction of the friction ridge skin information A
reproduction of the friction ridge skin information left on an
object when touchedleft on an object when touched
The transfer of material from a surface to the The transfer of
material from a surface to the friction ridge skin friction ridge
skin
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Evidentiary PrintsEvidentiary Prints
Latent / InvisibleLatent / Invisible Ridge impressions caused by
the transfer of body Ridge impressions caused by the transfer of
body
perspiration or oils to the surface of an object perspiration or
oils to the surface of an object requiring development or
enhancement for their requiring development or enhancement for
their visualizationvisualization
Patent / VisiblePatent / Visible Ridge detail transferred to a
surface after the Ridge detail transferred to a surface after
the
ridges have been in contact with a colored ridges have been in
contact with a colored material such as blood, paint, grease, or
inkmaterial such as blood, paint, grease, or ink
Plastic / ImpressionPlastic / Impression Ridge impressions left
on a soft material such as Ridge impressions left on a soft
material such as
putty, wax, soap or dustputty, wax, soap or dust
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Exemplar PrintsExemplar Prints
The The intentionalintentional recording of friction ridge skin
recording of friction ridge skin from a known individual in a
controlled from a known individual in a controlled environment for
documentation, environment for documentation, classification, or
comparisonclassification, or comparison
Form of collectionForm of collection Ten print cardTen print
card Major case recordsMajor case records PostPost--mortem
printsmortem prints
Examples of collection Arrest Military record Job requirement
Subpoena Drivers license Birth
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Friction Ridge ComparisonFriction Ridge Comparison
Identifications are affected by viewing Identifications are
affected by viewing these ridge characteristics taking into these
ridge characteristics taking into consideration their similarity,
their consideration their similarity, their number and their unit
relationship to number and their unit relationship to each
othereach other
NO UNEXPLAINABLE DIFFERENCESNO UNEXPLAINABLE DIFFERENCES
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Recording ExemplarsRecording Exemplars
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Recording ExemplarsRecording Exemplars
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Indented WritingIndented Writing
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Obliterated WritingObliterated Writing
OriginalOriginal Viewing with IR FilterViewing with IR
Filter
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Firearms and Firearms and ToolmarksToolmarks
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FirearmsFirearms
Firearms ExaminationsFirearms Examinations
Fired BulletsFired Bullets general characteristics such as
calibergeneral characteristics such as caliber physical features of
rifling impressionsphysical features of rifling impressions
manufacturer of bulletsmanufacturer of bullets
Cartridge Cases or Cartridge Cases or ShotshellShotshell
CasingsCasings caliber or gaugecaliber or gauge
manufacturermanufacturer presence of marks for comparisonpresence
of marks for comparison
Shot Pellets, Buckshot, SlugsShot Pellets, Buckshot, Slugs size
of shotsize of shot gauge of sluggauge of slug
manufacturermanufacturer
WaddingWadding components can determine gauge and
manufacturercomponents can determine gauge and manufacturer
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FirearmsFirearms
Firearms Examinations, cont.Firearms Examinations, cont.
Gunshot ResidueGunshot Residue indication of holding/firing
weaponindication of holding/firing weapon chemical
componentschemical components
Shot PatternShot Pattern type of guntype of gun distance from
muzzledistance from muzzle
Bullet and CasingBullet and Casing matched back to gun (ejector,
firing pin, breechblock, and extramatched back to gun (ejector,
firing pin, breechblock, and extractor marks)ctor marks) matched
back to same lot of ammunition found in suspect's possesmatched
back to same lot of ammunition found in suspect's
possessionsion
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FirearmsFirearms
A bullet is impressed A bullet is impressed with the rifling
with the rifling markings of the barrel markings of the barrel when
it emerges from when it emerges from the weapon.the weapon.
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Firearms ExaminationFirearms Examination
Photomicrograph of two bullets through a Photomicrograph of two
bullets through a comparison microscope. The test bullet is on
comparison microscope. The test bullet is on the right; the
questioned bullet is on the left.the right; the questioned bullet
is on the left.
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Physical MatchingPhysical Matching
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Crime Scene SearchCrime Scene Search
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History of Forensic ScienceHistory of Forensic Science
Forensic Science TimelineForensic Science TimelineNorah Norah
RudinRudin
www.forensicdna.com/Timeline.htmwww.forensicdna.com/Timeline.htm
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ReferencesReferences 11 SafersteinSaferstein, R., , R.,
CriminalisticsCriminalistics An Introduction to Forensic An
Introduction to Forensic
Science, Science, 44thth ed., Englewood Cliffs, N.J.:
Prenticeed., Englewood Cliffs, N.J.: Prentice--Hall, Inc., Hall,
Inc., 1990.1990.
22 DeForestDeForest, P.R., , P.R., GaensslenGaensslen, R.E., and
Lee, H.C. , R.E., and Lee, H.C. Forensic Forensic Science An
Introduction to Science An Introduction to
CriminalisticsCriminalistics, , New York,New York,
McGrawMcGraw--Hill, Inc. 1983.Hill, Inc. 1983.
33 KuzmackKuzmack, N.T.: Legal Aspects of Forensic Science, in
R. , N.T.: Legal Aspects of Forensic Science, in R.
SafersteinSaferstein (ed.), (ed.), Forensic Science Handbook,
Forensic Science Handbook, Englewood Cliffs, Englewood Cliffs,
N.J.: PrenticeN.J.: Prentice--Hall, Inc., 1982.Hall, Inc.,
1982.
44 Kirk, P.L., Kirk, P.L., Crime Investigation, Crime
Investigation, 22ndnd ed., New York: John Wiley ed., New York: John
Wiley & Sons, Inc., 1974.& Sons, Inc., 1974.
55 ChisumChisum, W.J. and , W.J. and TurveyTurvey, B.: Evidence
Dynamics: , B.: Evidence Dynamics: LocardsLocardsExchange Principle
& Crime Reconstruction, Exchange Principle & Crime
Reconstruction, Journal of Journal of Behavioral Profiling,
Behavioral Profiling, January, 2000, Vol. 1, No. 1.January, 2000,
Vol. 1, No. 1.
Vermont Forensic LaboratoryPhysical Comparison UnitLocards
Exchange PrincipleLocards Exchange PrincipleWhat is Forensic
Science?What is a Forensic Scientist?What is considered
evidence?What is NOT forensic evidence?The value of
evidencePhysical Comparison UnitFingerprintsWhat is a
Fingerprint?Other types of friction
skinLoopsWhorlsArchesFingerprint Individual CharacteristicsEnding
RidgeBifurcationDotScientific BasisUniquenessPermanenceLatent
PrintsEvidentiary PrintsExemplar PrintsFriction Ridge
ComparisonRecording ExemplarsRecording ExemplarsIndented
WritingObliterated WritingFirearms and
ToolmarksFirearmsFirearmsFirearmsFirearms ExaminationPhysical
MatchingCrime Scene SearchHistory of Forensic ScienceReferences