111Trace EvidenceTrace EvidenceHairHairNS2232 - LittlefieldTrace EvidenceTrace Evidence----any small pieces of any small pieces of material, manmaterial, man--made or naturally made or naturally occurringoccurringMost common examples:Most common examples:HairHairFiberFiberNS2232 - LittlefieldQuestions for Trace EvidenceQuestions for Trace EvidenceWhat is it?What is it?Is it manIs it man--made or natural?made or natural?What is its source?What is its source?How common is it?How common is it?Can it be identified to a single Can it be identified to a single source?source?NS2232 - Littlefield2From hair one can determine:From hair one can determine:Human or animalHuman or animalRaceRaceOriginOriginManner in which hair was removedManner in which hair was removedTreated hairTreated hairDrugs ingestedDrugs ingestedNS2232 - Littlefield3Hair StructureHair StructureHair Cuticle Scale TypesHair Cuticle Scale TypesMosaicMosaicPectinatePectinateImbricateImbricatePetalPetalDiamond petalDiamond petalChevronChevronNS2232 - LittlefieldScale TypesScale TypesMosaicChevron4Scale Types (cont)Scale Types (cont)PetalDiamond PetalScale Types (cont)Scale Types (cont)Pectinate ImbricateHuman HairHuman Hair5Human HairHuman HairCat HairCat HairCow HairCow Hair6Dog HairDog HairBat HairBat HairHair StructureHair Structure7Hair CortexHair CortexThe cortex gives the hair its shape.The cortex gives the hair its shape.It has two major characteristicsIt has two major characteristics::MelaninMelaninCortical Cortical fusifusiNS2232 - LittlefieldHair StructureHair StructureContinuousContinuousIntermittent or interruptedIntermittent or interruptedFragmentedFragmentedAbsentAbsent----not presentnot presentHair Medulla TypesHair Medulla TypesNS2232 - Littlefield8Hair Medulla PatternsHair Medulla PatternsUniserialMultiserialVacuolatedLatticeNS2232 - LittlefieldHuman medullaHuman medullaHuman medulla may be continuous, Human medulla may be continuous, fragmented or absent.fragmented or absent.9Rabbit medullaRabbit medullaDouble MedullaDouble MedullaMedullaryMedullaryIndexIndex Medullary Index for human hair is generally less than 1/3. For animal hair, it is usually greater than 1/2.10Hair GrowthHair GrowthAnagenAnagen----hair that is growinghair that is growingCatagenCatagen----hair at resthair at restTelogenTelogen----hair that is dyinghair that is dyingNS2232 - LittlefieldHow/When Did It Leave?How/When Did It Leave?TelogenAnagenEthnicityEthnicityBlackAsianCaucasian11CrossCross--SectionsSectionsCaucasianBlackAsianDyed Human HairDyed Human HairDNADNAMitochondrialMitochondrialNuclearNuclearNS2232 - Littlefield12Collection of Hair EvidenceCollection of Hair EvidenceQuestioned hairs Questioned hairs Known/Control SampleKnown/Control Sample––50 full50 full--length hairs from all areas of scalplength hairs from all areas of scalp––24 full24 full--length pubic hairslength pubic hairsNS2232 - LittlefieldHair ToxicologyHair ToxicologyAdvantages:Advantages:––Easier to collect and storeEasier to collect and store––Is externally availableIs externally available––Can provide information on the Can provide information on the individualindividual’’s history of drug use.s history of drug use.Collections must be taken from Collections must be taken from different locations on the body to different locations on the body to get an accurate timeline.get an accurate timeline.NS2232 - LittlefieldBucklingBuckling13Razor CutRazor CutEgg CaseEgg