Forensic Science: Forensic Science: An IntroductionAn Introduction

Forensic ScienceForensic Science

In its broadest definition it is the In its broadest definition it is the application of science to lawapplication of science to law

Applies to the knowledge and technology Applies to the knowledge and technology of science for the definition and of science for the definition and enforcement of such lawsenforcement of such laws

DefinitionDefinition: the application of science to : the application of science to those criminal and civil laws that are those criminal and civil laws that are enforced by police agencies in a criminal enforced by police agencies in a criminal justice systemjustice system

Sciences involvedSciences involved

ChemistryChemistryBiologyBiologyPhysicsPhysicsGeologyGeologyForensic pathologyForensic pathologyForensic psychologyForensic psychologyForensic OdontologyForensic Odontology

History of Forensic ScienceHistory of Forensic Science

Sir Arthur Conan DoyleSir Arthur Conan Doyle: fictional character : fictional character Sherlock HolmesSherlock Holmes had a great influence on had a great influence on popularizing the study of crime scenespopularizing the study of crime scenes

Holmes was the first to apply the principles Holmes was the first to apply the principles of serology (blood typing and analysis), of serology (blood typing and analysis), fingerprinting, firearm identification and fingerprinting, firearm identification and document examinationdocument examinationFirst book in 1887 “A Study in Scarlet”First book in 1887 “A Study in Scarlet”

Important PeopleImportant People

Mathieu OrfilaMathieu Orfila (1787-1853) father of (1787-1853) father of forensic toxicology; detection of poisons forensic toxicology; detection of poisons and their effectsand their effects

Alphonse BertillonAlphonse Bertillon (1853-1914) scientific (1853-1914) scientific system for personal identification; taking system for personal identification; taking body measurementsbody measurements as a means of as a means of distinguishing people; father of criminal distinguishing people; father of criminal identificationidentification

Important PeopleImportant People

Francis GaltonFrancis Galton (1822-1911) study of (1822-1911) study of fingerprintsfingerprints and developed method for and developed method for classifyingclassifying them for filing them for filing

Karl LandsteinerKarl Landsteiner in 1901 discovered ABO in 1901 discovered ABO blood typesblood types

Leone LattesLeone Lattes (1887-1954) devised a (1887-1954) devised a procedure for determining blood group of a procedure for determining blood group of a dried bloodstaindried bloodstain

Important PeopleImportant People

Calvin GoddardCalvin Goddard (1891-1955) (1891-1955) comparisoncomparison microscope to identify bulletsmicroscope to identify bullets

Albert OsbornAlbert Osborn (1858-1946) (1858-1946) documentdocument examinationexamination

Walter McCroneWalter McCrone (1916-2002) known as the (1916-2002) known as the world’s preeminent microscopist; instructor, world’s preeminent microscopist; instructor, and authorand author

Important PeopleImportant People

Hans GrossHans Gross (1847-1915) Austrian judge who (1847-1915) Austrian judge who described the described the application of scientific application of scientific disciplinesdisciplines to the field of criminal to the field of criminal investigation.investigation.Zoology, botany, anthropology, fingerprintingZoology, botany, anthropology, fingerprinting

Edmond LocardEdmond Locard (1877-1966) founder and (1877-1966) founder and director of the Institute of Criminalistics at director of the Institute of Criminalistics at the University of Lyons; workable the University of Lyons; workable crime labcrime lab

Important PeopleImportant People

Edmond Locard: Edmond Locard: Locard’s Exchange TheoryLocard’s Exchange Theory: the exchange of : the exchange of

materials between two objects that occurs materials between two objects that occurs whenever two objects come into contact with whenever two objects come into contact with one antherone anther

Locard believed every criminal can be Locard believed every criminal can be connected to a crime by dust particles carried connected to a crime by dust particles carried from the crime scenefrom the crime scene

Major influencersMajor influencers

#1 reason for increased need of trained #1 reason for increased need of trained scientists is the increase in drug sale and scientists is the increase in drug sale and usage in the worldusage in the worldAll illicit drug seizures must be sent to a All illicit drug seizures must be sent to a

forensic lab for confirmatory chemical analysis forensic lab for confirmatory chemical analysis before the case can go to courtbefore the case can go to court

4 Federal Crime Labs4 Federal Crime Labs FBIFBI: largest crime lab: largest crime lab DEADEA Drug Enforcement Agency: analysis of Drug Enforcement Agency: analysis of

drugs seized in violation of federal laws for drugs seized in violation of federal laws for production, sale and transportation of drugsproduction, sale and transportation of drugs

ATFE ATFE Bureau of Alcohol Tobacco Firearms and Bureau of Alcohol Tobacco Firearms and Explosives: responsible for analyzing alcoholic Explosives: responsible for analyzing alcoholic beverages and documents relating to tax law beverages and documents relating to tax law enforcement and for examining weapons, enforcement and for examining weapons, explosive devices, and related evidenceexplosive devices, and related evidence

U.S. Postal Inspection ServicesU.S. Postal Inspection Services: maintains lab : maintains lab concerned w/criminal investigations relating to concerned w/criminal investigations relating to the postal servicethe postal service

Crime Lab ServicesCrime Lab Services

Basic ServicesBasic ServicesPhotography Photography Physical Science Physical Science Biology/DNABiology/DNAFirearmsFirearmsDocument Document

ExaminationExamination

Optional ServicesOptional Services ToxicologyToxicology Latent FingerprintLatent Fingerprint PolygraphyPolygraphy Voice AnalysisVoice Analysis Forensic PsychiatryForensic Psychiatry Forensic OdontologyForensic Odontology Forensic EngineeringForensic Engineering Forensic Computer and Forensic Computer and

Digital AnalysisDigital Analysis

What Forensic Scientists DoWhat Forensic Scientists Do

Analyze physical evidenceAnalyze physical evidenceUse scientific methodsUse scientific methods

Determine admissibility of evidenceDetermine admissibility of evidenceFrye v US (1923) – general acceptanceFrye v US (1923) – general acceptance

Judge scientific evidenceJudge scientific evidenceDaubert case (1993) – trial judge is gatekeeperDaubert case (1993) – trial judge is gatekeeper

Provide expert testimonyProvide expert testimonyFurnish trainingFurnish training

Physical EvidencePhysical Evidence

Anything physical objects that can link a Anything physical objects that can link a crime to its victims or to suspects.crime to its victims or to suspects.

Has to be collected from crime sceneHas to be collected from crime sceneMust be relevant to the crime Must be relevant to the crime Requires the collector to understand what Requires the collector to understand what

the capabilities and limitations of the crime the capabilities and limitations of the crime lab arelab are

Physical EvidencePhysical Evidence

Crime labs do not solve crimes, only add Crime labs do not solve crimes, only add evidence to help police investigation link evidence to help police investigation link the suspect to the crime.the suspect to the crime.

The forensic scientists must know how to The forensic scientists must know how to collect and preserve evidence found at the collect and preserve evidence found at the crime scenecrime scene

Arriving at the Crime SceneArriving at the Crime Scene

Secure and isolate the crime sceneSecure and isolate the crime sceneDetermine boundaries of crime scene and Determine boundaries of crime scene and

priorities for evidence collectionpriorities for evidence collectionRough sketch Rough sketch Finished sketchFinished sketchPhotograph Photograph Videotaping Videotaping NotesNotes

Collecting EvidenceCollecting Evidence

Conduct a systematic search for evidence; Conduct a systematic search for evidence; be unabiased and thorough.be unabiased and thorough.

Field techniciansField techniciansWhat to look for depends on the crime and What to look for depends on the crime and

what specific locations of the crime scene what specific locations of the crime scene would most likely be affectedwould most likely be affected

Microscopic or massive objectsMicroscopic or massive objectsCollect carriers of possible evidenceCollect carriers of possible evidenceVacuum or sweeping collectedVacuum or sweeping collected

Packaging of EvidencePackaging of Evidence

Prevent any changes from occurring Prevent any changes from occurring (contamination, breakage, evaporation, (contamination, breakage, evaporation, bending, loss)bending, loss)

Process trace evidence from original Process trace evidence from original object (shirt, shoe) rather than isolating object (shirt, shoe) rather than isolating and packaging if possibleand packaging if possible

Package evidence separatelyPackage evidence separately

Tools for Collecting EvidenceTools for Collecting Evidence

ForcepsForcepsEvidence envelopes and pill bottlesEvidence envelopes and pill bottlesSwabsSwabsSpecial concerns (mold, evaporation)Special concerns (mold, evaporation)Various light sourcesVarious light sourcesLatent fingerprintsLatent fingerprintsMobile crime labs or better yet crime Mobile crime labs or better yet crime

scene search vehicle scene search vehicle

Chain of custodyChain of custody

Continuity of possession; every person Continuity of possession; every person who touched it must be accounted forwho touched it must be accounted for

Standards for collecting, labeling, and Standards for collecting, labeling, and submitting evidence forms are necessary submitting evidence forms are necessary for court for court

Labels include collectors initials, location Labels include collectors initials, location of evidence, date of collection. of evidence, date of collection. Identification numbers must also be usedIdentification numbers must also be used

Submission of EvidenceSubmission of Evidence

Standard/reference samplesStandard/reference samplesSubstance controlsSubstance controlsEvidence submission form will detail the Evidence submission form will detail the

evidence collect and particular type of evidence collect and particular type of examination/analysis requested. examination/analysis requested.

Lab tech not bound by requestsLab tech not bound by requests

Common Types of EvidenceCommon Types of Evidence Common Types of EvidenceCommon Types of Evidence Blood, semen, and salivaBlood, semen, and saliva DocumentsDocuments DrugsDrugs FibersFibers FingerprintsFingerprints Firearms and ammunitionFirearms and ammunition GlassGlass HairHair ImpressionsImpressions Organs and physiological Organs and physiological

fluidsfluids

PaintPaint Petroleum productsPetroleum products Plastic bagsPlastic bags Plastic, rubber, and other Plastic, rubber, and other

polymerspolymers Powder residuesPowder residues Serial numbersSerial numbers Soil and mineralsSoil and minerals Tool marksTool marks Vehicle lightsVehicle lights Wood and other Wood and other

vegetative mattervegetative matter

Examination of Physical EvidenceExamination of Physical Evidence

IdentificationIdentification Determining the identity of a substance with a near Determining the identity of a substance with a near

absolute certainty while ruling out other substancesabsolute certainty while ruling out other substances

ComparisonComparison Comparing the evidence to one or more selected Comparing the evidence to one or more selected

references and drawing a conclusion about its origins.references and drawing a conclusion about its origins. Individual characteristics –properties of evidence that Individual characteristics –properties of evidence that

can be attributed to a common source with extremely can be attributed to a common source with extremely high certainty. (eg. fingerprints, DNA, bullets)high certainty. (eg. fingerprints, DNA, bullets)

Class characteristics – properties of evidence that can Class characteristics – properties of evidence that can be associated with a group and never with a single be associated with a group and never with a single source. ( eg. Blood type, tire marks)source. ( eg. Blood type, tire marks)

Significance of Physical EvidenceSignificance of Physical Evidence

Assessing the values of evidenceAssessing the values of evidence Class characteristics of evidence is valuable in Class characteristics of evidence is valuable in

corroborating events.corroborating events. Multiple class evidence can lead to a high level of Multiple class evidence can lead to a high level of

certainty of origincertainty of origin

Cautions and limitations of evidenceCautions and limitations of evidence A person can be exonerated or excluded from A person can be exonerated or excluded from

suspicion if evidence collected from the crime suspicion if evidence collected from the crime scene is different from the reference samples scene is different from the reference samples collected from the person.collected from the person.

Forensic DatabasesForensic Databases

One-on-one comparison requires a suspectOne-on-one comparison requires a suspect Computerized databases help link evidence to Computerized databases help link evidence to

peoplepeople Fingerprint databases – IAFISFingerprint databases – IAFIS DNA database – CoDISDNA database – CoDIS Ballistics database – IBISBallistics database – IBIS Automative Paint database – PDQAutomative Paint database – PDQ Shoeprint database - SICaRShoeprint database - SICaR