AB,+TG,+MK

Anna, Thompson, and Maggie

__**Vocabulary:**__

 * Class Evidence**: “Material that connects an individual or thing to a certain group.”


 * Comparison Microscope**: “A compound microscope that allows the side-by-side comparison of samples, such as of hair of fibers.”


 * Cortex**: “The region of a hair located outside of the medulla containing granules granules of pigment.”


 * Cuticle:** “The tough outer covering of a hair composed of overlapping scales”


 * Hair Follicle**: “The actively growing root or base of a hair containing DNA and living cells.”


 * Individual Evidence:** “A kind of evidence that identifies a particular person or thing”


 * Keratin:** “A type of fibrous protein that makes up the majority of the cortex of a hair.”


 * Medulla:** “The central core of a hair fiber”


 * Melanin Granules:** “Bits of pigment found in the cortex of a hair.”


 * Neutron Activation Analysis:** “A method of analysis that determines composition of elements in a sample.”


 * Trace Evidence:** “Small but measurable amounts of physical or biological material found at a crime scene.”

→ Hair is considered Class Evidence. → Must have follicle cells attached to the hair in order to identify a specific individual → Hair does not decompose easily, can be analyzed at any point. → DNA evidence can be obtained through the follicle of the hair - DNA results are classified as Individual Evidence → Human hair grows at a rate of 1.3 cm a month
 * Random Facts:**

→ Main purpose is to regulate body temperature- keeps body warm, allows body to cool. → Protects against sunlight → If outside air is cold- muscles pull hair strands up which form air pockets, insulating head → If air is warm, muscles relax, flattening the hair and allowing trapped air to release
 * Function of Hair:**

A. 2 Parts 1. __Follicle:__ Club-shaped structure inside skin 2. __Shaft:__ Composed of keratin (protein), made up of chain of amino acids which make hair strong. → __Papilla:__ Blood vessels located at the end of the follicle, which provide nutrients to feed the hair. → __Sebaceous Gland:__ Secretes oil which keeps hair oily and conditioned.
 * Structure of Hair:**



The Medulla is not in everyone's hair 1. __Continuous__: One unbroken line of color 2. __Interrupted__: Pigmented line broken at regular intervals 3. __Fragmented or Segmented:__ Pigmented line unevenly spaced 4. __Solid:__ Pigmented area filling both the medulla and the cortex 5. __None:__ No separate pigmentation in the media → Largest part of hair shaft → Contains most of pigment granules that give hair color (melanin) → Made up of scales on outside of hair, observing the way in which the scales point show if the person is younger or older.
 * Medulla Types:**
 * Cortex:**
 * Cuticle:**



→ Forensics people take into consideration 6 types of hair 1. Head Hair a. Cross-Section: Circular/elliptical shaped 2. Eyebrows and Eyelashes a. Cross-Section: Circular with tapering ends 3. Beard and Mustache a. Cross-Section: Thick and triangular 4. Underarm hair 5. Body hair a. Cross-Section: Oval or triangular, depends on shaving 6. Pubic hair a. Cross-Section: Oval or triangular
 * Hair From Different Parts of Body:**

3 Stages: No pattern 1. Anagen Stage: - lasts 1,000 days - 80-90% of all hair is in this stage - Cells around follicle are rapidly dividing 2. Catagen Stage: - 2% of hair growth and development - accounts for our hair turning gray 3. Telogen Stage: - 10-18% of hairs in this stage - Follicle is dormant, hair is easily lost
 * Life Cycle of Hair:**

**Important!**



→ One can estimate when a hair was last dyed or colored → The region near root of hair will be colored naturally → If you measure the length of the hair that is naturally colored and divide by 1.3cm (rate which hair grows per month), gives estimate to how many months ago the hair was colored.
 * Color Treated Hair as it Applies to an Investigation:**

-Locard's exchange principle-whenever two objects are in contact some transfer of material will occur -at a crime scene person will leave behind or pick up trace evidence -hair is a major example of trace evidence -hair is collected by plucking, shaking, and scraping surface, putting tape over surface so that the hair attaches to it, vacuumed from large surfaces, -hair from a crime scene is compared by an investigator from six major body regions of victim or suspect
 * Using hair in an investigation**

-hair is determined to be human or animal by using a low power compound microscope -length, color, and curliness are macroscopic characteristics -hair is viewed between 40 and 400 times through a microscope -a comparison microscope is used to view two different samples at once -phase contrast microscope is used to observe fine detail in hair structure -fluorescence microscopes indicates the presence of a dye or chemicals -electron microscope provides incredible detail of the surface or interior of the hair sample
 * Microscopy**

-poisoning by arsenic, lead, and drugs can be detected through chemical analysis of the hair -timeline can be made by measuring how fair the hair is form the root and where the toxins are in the sections of the hair shaft -Neutron activation analysis is used to determine concentrations of elements in the sample -the odds of two hair sample have the same different nine elements is about one in a million
 * Testing for substances in the hair shaft**

-if hair is ripped out blood and tissue attached to the follicle can be analyzed -hair follicle provides a more positive match than from the hair shaft -DNA can be extracted from cells in the hair follicle for DNA analysis
 * Testing the hair follicle**

In 1990 Eva Shoen was found dead from a gunshot in the head. The attempted to solve the case through ballistics, however they did not have enough information. Three years later a man called the police saying that he thought his brother Frank Marquis had committed the murder. The police learned that Marquis had been in the area when Shoen was killed and he had thrown two bundles of clothes out of his car on his way home to Arizona. When police recovered the bundles they found a single strand of hair the color and structure of Eva Shoen’s. Marquis confessed to the murder and was sentenced to 24 years in prison.
 * Case Study:**

In the 2004 murder of Jessica Dooley a single hair became the main evidence in solving the crime. A long beard hair was discovered on her and then sent to a crime lab for DNA along with other DNA from three men under speculation. DNA ruled out two of the men, but the third man Jared Rosling was matched with the beard hair and found guilty of homicide.
 * Case Study 2:**