A Simplified Guide To Footwear & Tire Track Examination

Transcription

1 A Simplified Guide To Footwear & Tire Track Examination

2 Introduction Whenaperpetratorhidesevidenceofacrime,it scommonlycalled coveringtheirtracks. Forinstance,anindividualburglarizesahomeand usesaclothtowipeawayanyfingerprintsbeforeleaving.hethinkshehas coveredhistrail;buthemaynotrealizetheimpressionshisshoesortires makecouldalsobeusedtolinkhimtothesceneofthecrime. Thesefootwearandtiretrackimpressionsarereferredtoas pattern evidence becausetheimpressionsformauniquepattern.shoesandboots leaveprintsandimpressionsspecifictotheirparticularbrand,styleandsize. Thetreadoneachtireofavehiclemayprovideinvestigatorswithsimilar information. (Courtesy*of*John*Black,*Ron*Smith*&*Associates)* Throughsearchabledatabasescompiledbymanufacturers,theFBIand otheragencies,examinerscanattempttoidentifythetypeoffootwearor tirethatmadeanimpression.withthisinformation,investigatorscan researchwhichretailerssellaparticularshoe,orwhichvehiclesare equippedwithaparticulartire.thisevidencecanthenbeusedtohelp determineifasuspectwaspresentatacrimesceneorexcludeapersonof interestfromtheinvestigation. Principles of Footwear & Tire Track Examination Thebasictheorybehindfootwearandtiretrackanalysisisthat,muchlike fingerprints,shoesandtiresmayleavebehindeitherprints(referredtoas imprints )orimpressionsthatcanbeexaminedbyinvestigators.thetype

3 ofevidenceleftbehinddependslargelyonthetypeofsurfacetraveled.for example,ashoewillleaveanimpressioninloosesand,butonahardsurface likeconcreteorlinoleum,itwillleaveanimprint.theseimprintsor impressionscanbecomparedtoasuspect sshoeoravehicle stireto determineiftheshoeortireisthesameonethatlefttheimpression. Asshoesandtiresareused,theirphysicalfeatureschangeovertime.Thisis calledwear,andisoftenreflectedintheimprintorpatternleftbehind.inthe caseofatiretrack,ifavehicleisoutofalignment,therightfronttiremaybe heavilywornontheouteredge,leavingauniquewearpattern.aforensic examinercanusethatwearpatternalongwiththetreadpatternand informationgainedfromdatabasesearchestopositivelymatchthat impressiontothesuspect svehicle. Duringtheexaminationofacrimesceneorotherlocation,iffootwearortire trackevidenceisfoundandcollected,examinerscancomparethese unknownimpressionstoknownimpressions,impressionsconnectedto othercrimesandimpressionevidencestoredinlawenforcementdatabases. Todothis,examinersusethreemaincharacteristicstoanalyzetheimprints andimpressions:class,individualandwear. Classcharacteristicsresultfromthemanufacturingprocessandare dividedintogeneralandlimited.generalclasscharacteristicsincludethose thatarestandardforeveryitemofthatmakeandmodel.limited characteristicsrefertovariationsthatareuniquetoacertainmold.for example,twotiresofthesamebrand,modelandsizewillhaveidentical treaddesignanddimensions,butmayhaveslightdifferencesdueto imperfectionsinthemoldsusedduringmanufacturing. Enlarged*image*of*a*tire*tread*shows*characteristics*unique*to*the*mold*used* to*create*this*tire*(red*arrows).*(courtesy*of*john*black,*ron*smith*&* Associates)*

4 Individualcharacteristicsareuniqueaspectsofaparticularshoeortire thatresultfromuse,notthemanufacturingprocess.thesecouldbefrom damagesuchasacut,gougeorcrack,oratemporaryalterationlikeastone ortwigstuckinthetread. Wearcharacteristicsresultfromthenaturalerosionoftheshoeortread causedbyuse.specificwearcharacteristicsincludethewearpattern,the basicpositionoftreadwear;thewearcondition,theamountordepthofthe wear;andwhereextreme,thedamagetoordestructionofthetread.for instance,thelocationandamountoftreadlossonaparticularbrandand styleofshoewillbedifferentforeachpersonwearingtheshoebasedon howandwheretheywalk,andthelengthoftimetheyhaveownedtheshoe. (Courtesy*of*NFSTC)* TheFBIcompilesandmaintainstheFootwearandTireTreadFilesdatabase containingmanufacturers informationandinformationfrompreviously submittedevidence.thisinformationcanbeusedbyexaminersor investigatorstodeterminethebrandnameandmodelofshoeortire imprintsandimpressionsfoundatcrimescenes.thenationalinstituteof Justicealsomaintainsalistofforensicdatabases ( Why and when is footwear & tire track examination used? Footwearand/ortiretrackevidencecanbefoundatmanycrimescenes includingbreakingandentering,assault,hitandrun,armedrobbery,rape andhomicide.forinstance,shoeprintsmaybefoundonthetileinthe

5 entrywayofaresidentialbreakrin,ortiretracksfoundalongadirtroadnear amurdervictim.atsomepointintime,theperpetratorarrivedatthescene, committedthecrime,andthenleftthesceneonfootorinavehicle. Thistypeofevidencecanprovidevaluableinformationtoinvestigators including: Wherethecrimeoccurred Thenumberofpartiesorvehiclespresent Thedirectionapersonmayhavetraveledbefore,duringorafterthecrime Whetherapersonwasonfoot Othercrimescenesconnectedtoaperpetrator Oneofthemostfamouscasesinvolvingshoeprintswasthe1995O.J. Simpsonmurdertrial.Thebloodyshoeprintsfoundonthewalkwayinfront ofnicolebrownsimpson scondominiumreceivedworldwidemedia attention.uponforensicexamination,theywereidentifiedasimprintsfrom thesoleofasizer12brunomaglishoe. Informationfromthemanufacturerindicatedthatonly299pairsofthissizeR 12shoeweresoldintheU.S.Twoofthesepairsweresoldata Bloomingdale sstoreinnewyorkwheresimpsonwasknowntohave shopped.however,simpsondeniedeverowningapairoftheseshoes.it wasn tuntilthe1996wrongfuldeathciviltrialthatpicturessurfacedof SimpsonataBuffaloBillsfootballgame,wearingapairofblackBrunoMagli shoesofthesamestylethatleftthebloodyshoeprints.thiswaskey evidenceintheciviltrialthatledtothejudgmentagainstsimpson. How It s Done EvidencethatMaybeExamined Footwearandtiretrackscanbedepositedonalmostanysurface,frompaper tothehumanbody.printsaredividedintothreetypes:visible,plasticand latent. Avisibleprintisatransferofmaterialfromtheshoeortiretothesurface. Thistypecanbeseenbythenakedeyewithoutadditionalaids.Forexample, bloodyshoeprintsleftonflooringortracksleftbymuddytiresona driveway.

6 Bloody*shoeprints*are*visible*on*tile*flooring.*(Courtesy*of*John*Black,*Ron* Smith*&*Associates)* AplasticprintisathreeRdimensionalimpressionleftonasoftsurface.This includesshoeortiretracksleftinsand,mudorsnow. Plastic*shoeprint*left*in*sand.*(Courtesy*of*Aubrey*Askins,*Tacoma*Police* Department)* Alatentprintisonethatisnotreadilyvisibletothenakedeye.Thistypeis createdthroughstaticchargesbetweenthesoleortreadandthesurface. Examinersorinvestigatorsusepowders,chemicalsoralternatelightsources tofindtheseprints.examplesincludeshoeprintsdetectedonatileor hardwoodfloor,windowsill,ormetalcounter,ortiretracksdetectedon roadsurfaces,drivewaysorsidewalks.

7 Dust*impression*left*on*a*masonite*surface,*illuminated*with*oblique*lighting.* (Courtesy*of*Scott*Campbell,*Ron*Smith*&*Associates)* HowSamplesareCollected Examinersuseseveralmethodsforcollectingfootwearandtiretrack evidencedependingonthetypeofimpressionfound.forimpressionsinsoil, snoworothersoftsurfaces,castingisthemostcommonlyusedcollection method.forimprints,examinersgenerallytrytocollecttheentireobject containingtheimprint,suchasawholesheetofpaperorcardboardwitha shoeprint.whenthatisnotpossible,forinstance,iftheprintisonabank counter,theexaminerwouldusealiftingtechniquetotransfertheimprint toamediumthatcanbesenttothelaboratory. Casts*are*created*of*footwear*impressions*to*preserve*them*and*allow*for* comparison*and*analysis.*(courtesy*of*nfstc)*

8 Aswithanyevidencefoundatacrimescene,shoeprintsandtiretracksmust beproperlydocumented,collectedandpreservedinordertomaintainthe integrityoftheevidence.impressionevidenceiseasilydamaged,sosteps mustbetakentoavoiddamagetotheevidence.thisincludessecuringand documentingthescenepriortocollectinganyevidence. Inthecaseofimpressionevidence,generalphotographsoftheevidence locationinrelationtotherestofthescenearetaken,alongwithhighr resolutionimagesoftheindividualimprintsorimpressions.examinersmay usealternatelightsourcesorchemicalenhancerstocaptureasmuchdetail aspossible,especiallywithlatentimprints. Properlyphotographingimpressionsiscrucial.Sincethereisonlyaslight differencebetweendifferentshoesizes,ifthephotographsarenottakenata 90 angletotheimpression,thenthetruesizecannotbeproducedinorder tocomparetotheactualshoe. Wheneverpossible,impressionevidenceiscollectedasisandsubmittedto thelaboratoryforexamination.forshoeprintsandtiretracksthatcannotbe pickedup,variousliftingtechniquesareusedtorecovertheevidence.these include: AdhesivelifterRaheavycoatingofadhesiveliftstheimprintfromsmooth, nonrdelicatesurfacessuchastileorhardwoodfloors,metalcounters,etc.it isusuallyusedinconjunctionwithfingerprintpowders. GelatinlifterRasheetofrubberwithalowRadhesivegelatinlayeronone sidethatcanliftprintsfromalmostanysurface,includingporous,rough, curvedandtexturedsurfaces.itislesstackyandmoreflexiblethanan adhesivelifter,allowingittopickupadustyshoeprintonacardboardbox, forexample,butnottearthesurfaceofthebox. Electrostaticdust>printliftingdeviceRatoolthatelectrostaticallycharges particleswithindustorlightsoil,whicharethenattractedandbondedtoa liftingfilm.thismethodisbestforcollectingdryordustyresidue impressionsonalmostanysurface,eventheskinofacadaver. Anyplastic,orthreeRdimensional,footwearortireimpressionscanbe collectedbycasting.castingusesapowderedstonematerial,suchasdental stone,thatcanbemixedwithwaterandpouredintotheimpression.whenit dries,thismethodcreatesathreerdimensionalmodeloftheimpression. Imprintsandimpressionsmaybefurtherprocessedtoenhanceorbringout additionalminutedetails.forexample,adigitalenhancementprogramsuch asadobephotoshop canbeusedtoimprovethequalityofaphotographed tiretrack.fingerprintpowdersandchemicalstainsordyescanenhance

9 imagecolororincreasethecontrastagainstthebackground.thisenables liftedorcastedevidencetobephotographedorscanned. A*faint*bloody*shoe*print*on*linoleum*is*enhanced*by*treatment*with*a* chemical,*bluestar,*to*allow*a*more*detailed*photograph*to*be*taken*of*the* evidence.*(courtesy*of*erik*savicke,*boston*pd)* Comparisonsamplesareusuallytakenfromsuspectsorsuspectvehicles. ShoesamplesshouldbepackagedtoavoidcrossRcontaminationandtire samplesshouldremainonthevehicle. A*reference*print*from*a*tire*is*captured*by*inking*the*tire*and*driving*over* paper.*(courtesy*of*john*black,*ron*smith*&*associates)* WhoConductstheAnalysis Evaluationandcomparisonofimpressionevidenceshouldbeperformedby awellrtrainedfootwearandtiretrackexaminer.typicallythese professionalshavereceivedextensivetrainingonfootwearandtire manufacturing,evidencedetection,recovery,handlingandexamination procedures,laboratoryandphotographyequipmentandprocedures, courtroomtestimonyandlegalissues,andcasework.

10 TheScientificWorkingGrouponShoeprintandTireTreadEvidence (SWGTREAD)( discussestheminimumqualificationsandtrainingforfootwear/tiretrack examiners.additionally,theinternationalassociationforidentification(iai) ( footwearandtiretrackexaminersthattakesparticipantsthroughmorethan 550hoursoftraining.TheIAIalsocertifiesfootwear(butnottiretrack) examiners. HowandWheretheAnalysisisPerformed Detection,documentation,photography,andcollectionofimprintsand impressionsoccurinrelationtocrimescenesofmanytypes.analysisof impressionevidenceistypicallyperformedatapubliccrimelaboratoryor privatelaboratorybyexperiencedexaminers. Evidence Submission and Examination Ideally,thesuspect sshoesand/ortiresaresubmittedtothelabalongwith thecollectedevidence.examinerswillusethesubmittedshoesand/ortires tomaketeststandards,impressionsofaknownsource,whichcanthenbe comparedtothecollectedevidence.thisisusuallydoneusingtransparency overlaysorsiderbyrsidecomparisons. Forexample,inacasefromFlorida,abloodyshoeprintwasfoundonthe carpetinthehomeofamurdervictim.theprintindicatedthattherewasa holeintheshoethatlefttheprint.investigatorscollectedandmadetest printsoftheshoesfromindividualsknowntobeatthescenenearthetime ofthemurder.footwearexaminerswereabletoidentifytheperpetratorby overlayingthebloodyshoeprintfromthecrimescenewiththetestprint madefromthesuspect sshoe. Insomecases,aninvestigatormaybeaskedtosubmitshoesortiresofother individualsforexclusionpurposes,suchasfromacohabitantofahomeor fromafirstrespondertoacrimescene. Tools and Techniques Duringtheexaminationandcomparison,examinersusetoolssuchas dividers,calipers,speciallightingandlowmagnification.examiners measurethevariouselementswithinthetreaddesignaswellasthelength andwidthoftheimpressions,andthencomparethosemeasurementsto whatisseeninthecrimesceneprintorimpressions.lowmagnificationand speciallightingaresometimesusedtodetermineifvariouscharacteristics

11 areaccidentalorsomethingthatwascreatedduringthemanufacturing process. ExaminersperformsideRbyRsidecomparisonsbyplacingtheknownshoeor tirealongsidethecrimesceneprintsothatcorrespondingareascanbe examined.testprintsarealsocomparedtothecrimesceneprint.digital imagesondoubleortriplecomputermonitorscanalsobeusedduringthe comparison. Resources and References Investigatorsorexaminersoftenusesearchabledatabasescontaining referencefilesofshoeoutsolesandtiretreadstodeterminethe brand/modelofashoeortire.thefbi,privateconsultantsandfeerbased commercialsystemsmaintaindatabaseswithtensofthousandsofprints. Ofteninvestigatorscancontactthemanufacturerdirectlytoobtain informationandimagesforaspecificshoeortire. TheFBI scriminaljusticeinformationsystem(cjis)maintainsthefootwear andtiretreadfilesdatabase.theswgtreadwebsite videostoassistinvestigatorsandexaminers. Someagenciesusedatabasestostorecrimesceneimagesofshoesandtires, andtosearchandcomparecrimetocrime.searchingthesedatabasesdoes notfindpotential matches asautomatedfingerprintidentificationsystems can,butreturnstreaddesign lookralikes forfootwearandtiretread. FAQs Whatkindofresultscanbeexpectedfromtheanalysis offootwearandtiretracks? Footwear/tiretrackexaminationresultsarepresentedinareportthat presentstheexaminer sobservationsandconclusions,andmayalsoinclude supportingdetails,suchasthelevelofassociationbetweenthesuspect s shoeortireandtheprintorimpressionfromthecrimescene. Forensicfootwearandtiretrackexaminationsresultinoneoffourpossible determinations:anindividualization,anelimination,inconclusiveresultsor anassociation. Anindividualizationiswhentheclass,wearandindividualcharacteristics ofthecollectedimpressionandtheknownshoeortiresufficientlymatch withnounexplainabledifferences.

12 Anelimination(exclusion)iswhentheclass,wearand/orindividual characteristicsdonotsufficientlymatchbetweenthecollectedimpression andtheknownshoe/tire. Aninconclusiveresultoccurswhenthereisnotsufficientqualityor quantityofinformationfromthequestionedimpressiontoreacha meaningfulscientificconclusion. Anassociation(likelihood)canbedrawnwhentheclass,wearandsome individualcharacteristicsagreebetweenthecollectedimpressionandthe knownshoe/tire,butarenotsufficienttobecertainofamatch.resultscan rangefromlikelytocould*have,tosimilar*but*lacking*sufficient*detail*to*be* conclusive. Whatarethelimitationsoftheanalysis? Theanalysisessentiallyrequirestwothings:1)theprint,trackor impressionevidence,and2)comparisonshoesortires.theanalysisusually dependsontheconditionoftheevidence.iftheevidencehasbeencollected properly,andifthesubstrate(soil,snow,etc.)retainstheminutefeaturesof thetrack,adefinitiveopinioncanbereached. Howisqualitycontrolandqualityassurance performed? Toensurethemostaccurateanalysisofevidence,themanagementof forensiclaboratoriesputsinplacepoliciesandproceduresthatgovern facilitiesandequipment,methodsandprocedures,andanalystqualifications andtraining.dependingonthestateinwhichitoperates,acrimelaboratory mayberequiredtoachieveaccreditationtoverifythatitmeetsquality standards.therearetwointernationallyrecognizedaccreditingprograms focusedonforensiclaboratories:theamericansocietyofcrimelaboratory DirectorsLaboratoryAccreditationBoardhttp:// ANSIRASQNationalAccreditationBoard/FQShttp:// Indisciplinessuchasfootwearandtiretrackexamination,wheretesting requiresanalyststocomparespecificdetailsoftwosamples,qualitycontrol isachievedthroughtechnicalreviewandverificationofconclusions.this involvesanexpertorpeerwhoreviewsthetestdata,methodologyand resultstovalidateorrefutetheoutcome.theguidelinespublishedbythe ScientificWorkingGroupforShoeprintandTireTreadEvidence (SWGTREAD) trackcasesshouldbetechnicallyreviewedandverifiedbyasecond independentqualifiedexaminer.

13 Someoftheexaminationsconductedinthisforensicdisciplinearehandled byprivatecontractors.thesecontractorscanidentifythequalitycontrol andqualityassurancestepstheyemploy. Whatinformationdoesthereportincludeandhoware theresultsinterpreted? Thereporttypicallystateswhatwassubmittedforanalysisandthe conclusionoftheanalysis:individualization,elimination(exclusion), inconclusive,orassociation(likelihood).somereportsfromprivate laboratoriesincludephotographsoftheexaminationandconclusionofthe results. Arethereanymisconceptionsoranythingelseabout footwearandtiretrackexaminationthatmightbe importanttothenon>scientist? Whiletelevisioncrimedramasmightgivetheimpressionthatallthe evidenceatascenecanandwillbeidentified,inpractice,many opportunitiestocollectfootwearandtiretrackevidencecaneasilygo overlookediftheimpressionsarenotreadilyapparent.moreover,while shoeprintscanbeverydifficulttoprotectandcaneasilybedisturbedby firstrespondertrafficatacrimescene,theycanoftenstillbelocatedafter subjectedtosomefoottraffic. Anothermisconceptioninvolvestiretrackexamination.Onsomecrime dramas,adetectivesnapsaphotoofatiretrackonhiscellphoneand,using adatabaseorapp,instantlyretrievesthemake/model/numberofthetire.in reality,thereiscurrentlynoautomatedmethodformatchingtreadpatterns. Thepatternsmustbemeticulouslyphotographedanddocumented,then comparedmanuallyusingcomputerdatabasesandsometimesprinted referencebooks.theprocessistimeconsumingandevenifthetirecanbe identified,itisjustpartoftheworkneededtoconnectthetiretracktoa particularcarorindividual. Common Terms Adhesivelifter AnyvarietyofadhesiveRcoatedmaterialsortapesusedto liftfingerprintsorfootwearimpressions.primarilyusedtoliftpowdered impressionsfromnonrporoussurfaces. CastR

14 1.AmethodofmakingamoldbyfirstmakingathreeRdimensionalmodelof ashoeortireandthenformingthemoldfromthatmodel. 2.ThefillingofathreeRdimensionalfootwearortiretrackimpressionwith materialthattakesonandretainsthecharacteristicsthatwereleftinthat impressionbythefootwearortire. 3.AmethodusedintheliftingoftwoRdimensionalfootwearand/ortire impressionsfromroughsurfaces. Classcharacteristic Anintentionalorunavoidablecharacteristic(suchas physicalshape,physicalsize,treaddesign/elementsorwearposition)that repeatsduringthemanufacturingprocessandissharedbyoneormore othershoesortires. DOTnumber DepartmentofTransportationserialnumberassignedto everytiresoldintheunitedstates;itgivesinformationregardingthe manufacturer,sizeanddateofmanufactureofthetire. Electrostaticdustprintlifter AsystemthatappliesahighRvoltage electrostaticchargeonapieceofliftingfilm,causingdustorresidue particlesfromaprinttotransfertotheundersideoftheliftingfilm. Elimination(exclusion) Aneliminationisestablishedwhentheclass, wearand/orindividualcharacteristicspresentinthequestionedimpression donotagreewiththoseintheknownshoe/tire. Eliminationimpressions Testimpressionstakenfromtheshoesandtires offirstrespondersandotherknownindividualsforthepurposeof discerningtheseimpressionsfromthequestionedcrimesceneimpressions. Identification Thepositiveassociationofanimpressionashavingbeen madebyasingleshoe,totheexclusionofallothers. Inconclusive Aquestionedimpressionthatdoesnotexhibitsufficient qualityand/orquantityofinformationmaybedeemedinconclusive.this indicatesthatameaningfulscientificconclusioncannotbereached. Individualcharacteristic Somethinguniqueaboutthefootwearortire treadthatisnotsharedbyanyothershoeortire eventhosefromthesame productionrun.itcouldresultfromdamageorsometemporaryalteration, suchasastonecaughtinthetread. Latent Atypeofprintthatisnotvisibletothenakedeye. Lift Totransferanimpressionfromitsoriginalsurfaceforthepurposeof recoveringitfromthecrimesceneandforprovidingbettercontrast.

15 Negativeimpression Animpressionthatresultswhenthecontactareaof ashoeortireremovesresidue(suchasdust,paintorsomespilled substance)fromasurface,leavingbehinda clean imageoftheprintinthe residue. Outsole Thebottomportionoftheshoethatprovidesdurabilityand tractiononasurface.itistheoutersoleoftheshoe,fromthetoetothe beginningoftheheel,butexclusiveoftheheelitself.withleathersolesthe grainsideoftheleatherisalmostalwaysusedforthebottomfaceor exposedpart.inalooserorbroadersense, bottom mayincludeinsole and/ormidsole. Plastic AtypeofprintthatisthreeRdimensional. Positiveimpression Animpressionthatresultswhenashoeortire depositsmaterialontoasurface. Stonehold Acharacteristiccreatedwhenatreadcapturesandholdsa loosestone.stoneholdsareconsideredindividualcharacteristics. Tread Thedesignedpartoftheshoeortirethatcomesintocontactwith thegroundorroad. Wearcharacteristics Changesinthesurfaceoftheshoeoutsoleortire treadthatareobservableintheimpressionand/orknownshoeortire,and thatreflecttheerosionofthesurfaceoftheshoeoutsoleortiretread. Resources & References Youcanlearnmoreaboutthistopicatthewebsitesandpublicationslisted below. Resources InternationalAssociationforIdentification(IAI)FootwearCertification ScientificWorkingGrouponImagingTechnology(SWGIT) SWIGITGENERALGUIDELINESFORPHOTOGRAPHINGFOOTWEARANDTIRE TRACKEVIDENCESection9 Section10

16 ScientificWorkingGrouponShoeprintandTireTreadEvidence (SWGTREAD) References Bodziak,WilliamJ.FOOTWEARIMPRESSIONEVIDENCE,SecondEdition.CRC Press,BocaRaton,FL,2000. Colbry,D.;Cherba,D.;Luchini,J.PatternRecognitionforClassificationand MatchingofCarTires,TIRESCIENCEANDTECHNOLOGY2005,33(1),pp ForensicIdentificationTrainingandConsultingServices Foster+FreemanLtd.websiteforSICAR 6, =article&id=51:sicar&catid=2:shoe>print>identification&itemid=63 (accessedfeb.23,2012). Foster+FreemanLtd.websiteforSoleMate, =article&id=4:about>solemate&catid=2:shoe>print> identification&itemid=22(accessedfeb.23,2012). Foster+FreemanLtd.websiteforTreadMate, =article&id=30:treadmate&catid=2:shoe>print> identification&itemid=64(accessedfeb.23,2012). GuideforMinimumQualificationsandTrainingforaForensicFootwear and/ortiretreadexaminer, SWGTREADPublishedStandard, _qualifications_final_03>2006.pdf(accessedApril4,2012). Hilderbrand,DwaneS.FOOTWEAR,THEMISSEDEVIDENCE,2nded,Staggs PublishingCompany,Wildomar,CA,2007. LaboratoryPhysicalEvidenceBulletin#12:PRESERVATIONOFSHOEAND TIREIMPRESSIONS(online).QualityDocumentsProgram, Lyle,D.P. Chapter14:Impressions:Shoes,Tires,Tools,andFabrics, FORENSICS:AGUIDEFORWRITERS(Howdunit).Writer sdigestbooks: Cincinnati,OH(2008),pp.303R315. TireGuidesInc.

17 Acknowledgments Theauthorswishtothankthefollowingfortheirinvaluablecontributionsto thisforensicguide: DwaneS.Hilderbrand,Forensic*Consultant,ForensicIdentificationTraining andconsultingservices TanyaC.Hiner,Forensic*Specialist*IV,LatentPrintSection,KansasCity PoliceCrimeLaboratory

18 Forensic Evidence Admissibility and Expert Witnesses Howorwhysomescientificevidenceorexpertwitnessesareallowedtobe presentedincourtandsomearenotcanbeconfusingtothecasualobserver oralaypersonreadingaboutacaseinthemedia.however,thereis significantprecedentthatguidesthewaythesedecisionsaremade.our discussionherewillbrieflyoutlinethethreemajorsourcesthatcurrently guideevidenceandtestimonyadmissibility. TheFryeStandard ScientificEvidenceandthe PrincipleofGeneralAcceptance In1923,inFrye*v.*United*States [1],theDistrictofColumbiaCourtrejectedthe scientificvalidityoftheliedetector(polygraph)becausethetechnologydid nothavesignificantgeneralacceptanceatthattime.thecourtgavea guidelinefordeterminingtheadmissibilityofscientificexaminations: Just*when*a*scientific*principle*or*discovery*crosses*the*line*between*the* experimental*and*demonstrable*stages*is*difficult*to*define.*somewhere*in*this* twilight*zone*the*evidential*force*of*the*principle*must*be*recognized,*and* while*the*courts*will*go*a*long*way*in*admitting*experimental*testimony* deduced*from*a*wellqrecognized*scientific*principle*or*discovery,*the*thing* from*which*the*deduction*is*made*must*be*sufficientlyestablishedtohave gainedgeneralacceptance*in*the*particular*field*in*which*it*belongs.* Essentially,toapplythe FryeStandard acourthadtodecideifthe procedure,techniqueorprinciplesinquestionweregenerallyacceptedbya meaningfulproportionoftherelevantscientificcommunity.thisstandard prevailedinthefederalcourtsandsomestatesformanyyears. FederalRulesofEvidence,Rule702 In1975,morethanahalfRcenturyafterFrye*wasdecided,theFederalRules ofevidencewereadoptedforlitigationinfederalcourts.theyincludedrules onexperttestimony.theiralternativetothefrye*standardcametobeused morebroadlybecauseitdidnotstrictlyrequiregeneralacceptanceandwas seentobemoreflexible. [1]293Fed.1013(1923)

19 ThefirstversionofFederalRuleofEvidence702providedthatawitness whoisqualifiedasanexpertbyknowledge,skill,experience,training,or educationmaytestifyintheformofanopinionorotherwiseif: a. theexpert sscientific,technical,orotherspecializedknowledgewillhelpthe trieroffacttounderstandtheevidenceortodetermineafactinissue; b. thetestimonyisbasedonsufficientfactsordata; c. thetestimonyistheproductofreliableprinciplesandmethods;and d. theexperthasreliablyappliedtheprinciplesandmethodstothefactsofthe case. Whilethestatesareallowedtoadopttheirownrules,mosthaveadoptedor modifiedthefederalrules,includingthosecoveringexperttestimony. Ina1993case,Daubert*v.*Merrell*Dow*Pharmaceuticals,*Inc.,theUnited StatesSupremeCourtheldthattheFederalRulesofEvidence,andin particularfed.r.evid.702,supersededfrye s*"generalacceptance"test. TheDaubertStandard CourtAcceptanceofExpert Testimony InDaubertandlatercases [2],theCourtexplainedthatthefederalstandard includesgeneralacceptance,butalsolooksatthescienceanditsapplication. Trialjudgesarethefinalarbiteror gatekeeper onadmissibilityofevidence andacceptanceofawitnessasanexpertwithintheirowncourtrooms. Indecidingifthescienceandtheexpertinquestionshouldbepermitted,the judgeshouldconsider: Whatisthebasictheoryandhasitbeentested? Aretherestandardscontrollingthetechnique? Hasthetheoryortechniquebeensubjectedtopeerreviewandpublication? Whatistheknownorpotentialerrorrate? Istheregeneralacceptanceofthetheory? Hastheexpertadequatelyaccountedforalternativeexplanations? Hastheexpertunjustifiablyextrapolatedfromanacceptedpremisetoan unfoundedconclusion? TheDaubertCourtalsoobservedthatconcernsovershakyevidencecould behandledthroughvigorouscrossrexamination,presentationofcontrary evidenceandcarefulinstructionontheburdenofproof. [2]The DaubertTrilogy ofcasesis:daubertv.merrelldowpharmaceuticals,general ELECTRICCO.V.JOINERandKUMHOTIRECO.V.CARMICHAEL.

20 Inmanystates,scientificexperttestimonyisnowsubjecttothisDaubert standard.butsomestatesstilluseamodificationofthefryestandard. Whocanserveasanexpertforensicsciencewitnessat court? Overtheyears,evidencepresentedattrialhasgrownincreasinglydifficult fortheaveragejurortounderstand.bycallingonanexpertwitnesswhocan discusscomplexevidenceortestinginaneasyrtorunderstandmanner,trial lawyerscanbetterpresenttheircasesandjurorscanbebetterequippedto weightheevidence.butthisbringsupadditionaldifficultquestions.how doesthecourtdefinewhetherapersonisanexpert?whatqualifications musttheymeettoprovidetheiropinioninacourtoflaw? Thesequestions,too,areaddressedinFed.R.Evid.702.Itonlyallows experts qualified byknowledge,skill,experience,training,oreducation. Tobeconsideredatrueexpertinanyfieldgenerallyrequiresasignificant leveloftrainingandexperience.thevariousforensicdisciplinesfollow differenttrainingplans,butmostincludeinrhousetraining,assessmentsand practicalexams,andcontinuingeducation.oralpresentationpractice, includingmootcourtexperience(simulatedcourtroomproceeding),isvery helpfulinpreparingexaminersforquestioninginatrial. Normally,theindividualthatissuedthelaboratoryreportwouldserveasthe expertatcourt.byissuingareport,thatindividualtakesresponsibilityfor theanalysis.thispersoncouldbeasupervisorortechnicalleader,but doesn tnecessarilyneedtobetheonewhodidtheanalysis.theopposition mayalsocallinexpertstorefutethistestimony,andbothwitnessesare subjecttothestandardinusebythatcourt(frye,*daubert,fed.r.evid702) regardingtheirexpertise. Eachcourtcanacceptanypersonasanexpert,andtherehavebeen instanceswhereindividualswholackpropertrainingandbackgroundhave beendeclaredexperts.whennecessary,theopponentcanquestionpotential witnessesinanattempttoshowthattheydonothaveapplicableexpertise andarenotqualifiedtotestifyonthetopic.theadmissibilitydecisionisleft tothejudge. AdditionalResources Publications: Saferstein,Richard.CRIMINALISTICS:ANINTRODUCTIONTOFORENSIC SCIENCE,PearsonEducation,Inc.,UpperSaddleRiver,NJ(2007).

21 McClure,David.Report:FocusGrouponScientificandForensicEvidencein thecourtroom(online),2007, 19,2012) Acknowledgements Theauthorswishtothankthefollowingfortheirinvaluablecontributionsto thisguide: RobinWhitley,Chief*Deputy,AppellateDivision,DenverDistrictAttorney s Office,SecondJudicialDistrict DebraFigarelli,DNA*Technical*Manager,NationalForensicScience TechnologyCenter,Inc. About This Project ThisprojectwasdevelopedanddesignedbytheNationalForensicScience TechnologyCenter(NFSTC)underacooperativeagreementfromtheBureau ofjusticeassistance(bja),award#2009rd1rbxrk028.neithertheu.s. DepartmentofJusticenoranyofitscomponentsoperate,control,are responsiblefor,ornecessarilyendorse,thecontentsherein. NationalForensicScienceTechnologyCenter NFSTCScience*Serving*Justice thAvenueNorth Largo,Florida33773 (727)549R6067 info@nfstc.org