Warm-UpSeptember 19, 2014

• How could hair be used in the analysis of a crime scene?

Hair

“For three days after death, hair and fingernails continue to grow but

phone calls taper off.”

—Johnny CarsonComedian and television host

Objective

SWBAT describe the morphology of hair.

Agenda

1. Physical Evidence Review

2. Morphology of Hair

3. Atlanta Child Murders Documentary

4. Location of Hair

5. Hair Ethnicity

6. Hair Analysis Lab

7. DNA & Toxicology

8. Forensic Files Friday

9. Exit Slip

Physical Evidence

• Physical evidence results from the transfer of material from one place to another.

• Examples include:– paint chips– gunshot residue– glass fragments– paint– hair– bodily fluids– fingerprints

Physical Evidence

• Physical evidence can be classified as follows:– individual characteristics

• identify a single source, such as DNA

– class characteristics• associated with a particular characteristic, but

not necessarily an individual, such as blood type

• Fibers are always class evidence. Hair may be either individual or class evidence.

Physical Evidence

• Sir Edmond Locard, “The Sherlock Holmes of France,” formed the first police laboratory in 1910 to study trace evidence.

• Locard’s principle: “Every contact leaves a trace.”

• When a crime is committed, material will be mutually exchanged between the perpetrator and the crime scene.

• It is up to the investigator to identify materials that are seemingly foreign to the location.

Physical Evidence

• The amount of physical (or trace) evidence transferred depends on the nature and duration of contact, as well as the type of contacting surfaces.

• Trace evidence transfer is more likely to be found in brutal crimes occurring over a long period of time than in the case of less forceful encounters.

Physical Evidence

• Investigators must use caution when entering a crime scene to avoid:– introducing new trace evidence– destroying existing evidence

• As time passes after a crime more evidence is lost.

• Elimination standards are often collected from crime scene personnel to exclude them as the source of evidence.

Evidence Collection

• When investigators arrive at a secured scene, the following events will be prioritized:1. collect large evidence with a careful

walkthrough2. collect trace evidence3. process the scene for fingerprints and

biological evidence

• This procedure maximizes the preservation of evidence from a crime scene.

Introduction

Frequently found at the scene of a violent crime.

Provides a link between the criminal and the crime

From hair one can determine: Source (human or animal) Race (sometimes) Origin of the location on the source’s body Whether the hair was forcibly removed If the hair has been treated with chemicals If drugs have been ingested

Skin Structure

Hair ShaftComposed of:

Cuticle—outside covering, made of overlapping scales

Cortex—inner layer made of keratin and imbedded with pigment; also contains air sacs called cortical fusi

Medulla—inside layer running down the center of the cortex

The Cuticle• Outermost layer of hair• Covered with scales

• point toward the tip of the hair • differ between species of animals• named based on their appearance

• The three basic patterns are: Coronal Spinous Imbricate

Human ScalesIn order to visualize thescales: paint clear fingernail

polish on a glass slide when the polish begins to

dry, place a hair on the polish

when almost dry, lift off the hair and observe the scale imprints

What pattern is seen inthis slide?

The Cortex

Gives the hair its shape

Two major characteristics: Melanin—pigment granules that give hair its

color

Cortical fusi—air spaces, usually found near

the root but may be found throughout the hair

shaft

The Medulla

Hair core Not always visible

Types: Intermittent or interrupted Fragmented Continuous Stacked Absent—not present

Human MedullaHuman medulla may be continuous,

fragmented or absent.

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.

For animal hair, it is usually greater than 1/2.

mouse

Hair Shape

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)

Hair Growth

Terminology

Anagen—hair that is actively growing; lasting up to 5 years

Catagen—hair is not growing; a resting phase

Telogen—hair that is dying and ready to fall out; lasting two to six months

Grows about 0.5 mm per day or 1 centimeter per month; approximately one half inch per month

The RootHuman roots look different based on whether they have been forcibly removed or if they are telogen hairs and have fallen out. Animal roots will vary, but in general have a spear shape.

Fallen out Forcibly removed

Atlanta Child Murders Documentary1. What did Wayne Williams say was the reason

that police were there? 2. What was the first clue that was found on Eric’s

shoe? 3. What was the disturbing pattern of the murders? 4. What was the reaction of the police when one of

the mothers went to the police? 5. How long did it take for police to create a task

force? 6. Why did they think the suspect was black? 7. What were some of the fiber types that were

found? 8. What was the breakthrough in January of 1981?

Determining Hair Location

• In humans and animals the hair’s structure is influenced by where it grows on the body.

• The primary types of human hair used in forensic investigations come from either the scalp or pubic regions.

Determining Hair Location

• Scalp hairs are longer with a moderate shaft diameter and broken up medulla.

• Pubic hairs are more coarse and wiry. They have broad, continuous medullas throughout.

Determining Hair Location

• Scalp hairs show characteristics from grooming:– coloring– bleaching– split or cut ends

• Human hair grows at about ½ inch per month, giving an investigator the ability to measure the duration between a crime and an event such as coloring the hair.

Determining Hair Ethnicity

• Current FBI standards suggest human hairs can be classified into 3 broad categories:– Caucasoid (of European origin)

– Negroid (of African origin)

– Mongoloid (of Asian or Native American origin)

• Note that this designation is a purely microscopic analysis. Suspects may or may not identify with these racial groups.

Determining Hair Ethnicity

• Caucasoid class hairs have:– moderate shaft diameters (80µm) with

minimal variation– pigment granules at even intervals either

loosely or densely packed– oval cross-sections

Determining Hair Ethnicity

• Negroid class hairs have:– a wide range of shaft diameters– prominent twisting and curling shafts– pigment granules that are densely distributed

throughout (opaque under microscope)– flattened cross-sections

Determining Hair Ethnicity

• Mongoloid class hairs have:– large shaft diameters with little variation– broad medullas– thick cuticles– densely distributed pigment granules in

patchy areas or streaks– round cross-sections

Analysis Conclusions

• An examiner can form one of 3 conclusions from hair comparisons:1. Hairs from the known source have the same

characteristics as the evidence.2. Hairs from the evidence are different from

the known source.3. Hairs from the evidence have some

characteristics that match and some that do not match the known source, therefore no conclusion can be drawn as to whether the samples are from the same source.

Hair Analysis Lab

• Follow the directions and make sure that you draw the pictures and answer the questions on a separate sheet of paper.

DNA from Hair

Root contains nuclear DNA folicular tissue may be attached

containing DNA

Shaft contains abundant mitochondrial DNA,

inherited only from the mother typed by comparing relatives if no DNA

from the body is available ($$$)

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 Toxicology

Advantages: Easy to collect and store Is externally available Can provide information on the individual’s

history of drug use or of poisoning.

Collections must be taken from different locations on the body to get an accurate timeline.

Hair Toxicology Napoleon died in exile

in 1821. 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 did him in.

Forensic Files Friday

Homework

• Chapter 10 Review Questions, #1-14 due on Monday

Monday

• Mrs. Rieger will be your sub and you will be in the computer lab in the media center

Agenda

1.CSI Experience Activity

2.Complete previous Chapter 10 reading assignments

3.HW: Read pages 367-381 in Chapter 10.

Exit SlipSeptember 18, 2014

1. Get out a mobile device or use one of the computers and go to m.socrative.com. You can also use one of the iPads that has the Socrative app.

2. When prompted, enter 417101 for the room number.

QUESTION: How can you use hair to solve a crime?