Hair 1 Do Now: 1.Name the 5 fiber weave types. 2.What two parts of hair could be used to distinguish between ethnicities? 3.Describe the proper way to collect hair from a crime scene 4.Name the 5 fiber weave types AGAIN. 5.A victim was found at12:00pm with a temperature of 22 degrees. How long has this victim been dead? What time did he die? *If students are talking during Do Now – pop quiz (click here) Objective:. SWBAT understand how fibers are compared through physical and chemical analysis.

Hair 2 Fibers ‡determining what an attacker was wearing at the time of the incident. ‡identify the make of the garment and thus the manufacturer. ‡Hair and FiberHair and Fiber

Hair 3 Burn Test ‡Smoke ‡Smell ‡How the fiber burns ‡Ashes ‡Database

Hair 4 ‡Students will identify the various parts of a hair. ‡Students will describe the variations in the structure of the medulla, cortex and cuticle. ‡Students will distinguish between human and nonhuman animal hair. ‡Students will distinguish between hair between individuals and ethnicities. ‡Students will explain how hair can be used in a forensic investigation. ‡Students will identify and describe common weave patterns of textile samples. ‡Students will understand how fibers are compared various through physical and chemical analysis.

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Hair 6 Exit Ticket ‡Name the 3 layers of hair ‡Name the function of each layer ‡How can hair and fiber be useful in an investigation ‡What is a burn test ‡How can the medulla be used to narrow down the suspects.

Hair 7 Human Medulla Human medulla may be continuous, fragmented, or absent.

Hair 8 Medullary Index Determined by measuring the diameter of the medulla and dividing it by the diameter of the hair. Medullary index for human hair is generally less than 1/3 macrometers For animal hair, it is usually greater than ½ macrometers mouse

Hair 9 Hair Shape and Cross Section Can be straight, curly, or kinky, depending on the cross-section, which may be round, oval, or crescent-shaped. Round (Straight) Oval (Curly) Crescent moon (Kinky) Human hair ranges in diameter from µm

Hair 10 Racial Characteristics of Hair ‡Risky, but generally… ‡Asians & Native Americans – round cross section with no twisting ‡American & European whites, Mexicans, and people of Middle Eastern background – oval cross section, rarely with a twist or undulation. ‡African heritage – flat to crescent-shaped cross section with twist, undulation and dense, clumped pigmentation.

Hair 11 Hair Growth Grows 1 cm per month; approximately one-half inch per month Replaced about every 3-5 years with new hair

Hair 12 The Root Human roots look different based on whether they have been forcibly removed or they are telogen hairs and have fallen out. Animal roots vary, but in general have a spear shape. Fallen outForcibly removed

Hair 13 The Tip Tip of mature hair will taper to a point Recently cut hair is squared off at the tip, but within 2-3 weeks the tip becomes rounded Frayed hair tip results from over-processing (bleach, coloring, straighteners, blow dryer) or age

Hair 14 Hair Comparison Color Length Diameter Distribution, shape, and color intensity of pigment granules Scale types Presence or absence of medulla Medullary type Medullary pattern Medullary index Dyed hair has color in cuticle and cortex Bleaching removes pigment and gives a yellow tint

Hair 15 Exit Ticket ‡What details can microscopes give about hair characteristics? ‡Using hair characteristics, name some of the biggest difference between you and your groups. ‡The three layers of hair are: ‡A. Cuticle, Convex, Concave ‡B Convex, Medulla, Cuticle ‡C. Cuticle, Cortex, Medulla ‡D. Cuticle, Cortex, Mortem

Hair 16 DNA from Hair The root contains nuclear DNA. If the hair has been forcibly removed, some follicular tissue containing DNA may be attached. The hair shaft contains abundant mitochondrial DNA, inherited only from the mother. It can be typed by comparing relatives if no DNA from the body is available. This process is more difficult and more costly than using nuclear DNA.

Hair 17 Collection of Hair Questioned hairs must be accompanied by an adequate number of control samples. From victim From possible suspects From others who may have deposited hair at the scene Control sample 50 full-length hairs from all areas of scalp 24 full-length pubic hairs

Hair 18 Hair Toxicology Advantages : Easy to collect and store Is externally available Can provide information on the individual’s history of drug use or evidence of poisoning Collections must be taken from different locations on the body to get an accurate timeline.

Hair 19 Hair as Chemical Indicator ‡Metabolite – a specific product of a substance, formed by chemical processes in the body ‡Drugs and their metabolites, vitamins and poisons can be detected with just a few mm of hair. ‡Provides back up to urine and blood testing ‡Drug metabolites only detectable in urine for approx. 3-5 days from last use. ‡Hair grows at approx. 1 cm per month and will record drug use over a longer period of time. ‡Can establish dietary deficiencies and diseases ‡Oils on scalp can deposit onto hair and will leave evidence of environment ‡Smoke from crack cocaine can be deposited this way ‡May provide a false positive

Hair 20 Hair Toxicology, continued Napoleon died in exile in By analyzing his hair, some investigators suggest he was poisoned by the deliberate administration of arsenic; others suggest that it was vapors from the dyes in the wallpaper that killed him.

Hair 21 More about Hair For additional information about hair and other trace evidence, check out truTV’s Crime Library at: