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Unit 5: Forensic Anatomy :. This unit will cover the various body systems that can be used for forensic identification in various criminal investigations. Body fluids Topics covered will include: blood, blood typing and identification and blood splatter analysis Hair analysis Fingerprints

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Presentation Transcript
slide2

This unit will cover the various body systems that can be used for forensic identification in various criminal investigations.

  • Body fluids
  • Topics covered will include: blood, blood typing and identification and blood splatter analysis
  • Hair analysis
  • Fingerprints
  • bone and skeletal remains
  • DNA evidence
blood and the abo blood groups
BLOOD AND THE ABO BLOOD GROUPS
  • About 8% by weight of the average human body is blood.
  • This corresponds to about 5 L in the average person.
  • The three types of cells are erythrocytes (red blood cells, RBC), leukocytes (white blood cells), and thrombocytes (blood platelets).
serology
Serology

Serology is the examination and analysis of body fluids. A forensic serologist may analyze a variety of body fluids including saliva, semen, urine, and blood.

From 1950 to the late 1980’s, forensic serology was a most important part of lab procedures.

With the development of DNA techniques, more time, money, and significance was placed in developing DNA labs.

However, with limited funds and the time required for DNA testing, most labs still use many of the basic serology testing procedures.

blood characteristics
Blood Characteristics
  • Plasma is the fluid portion of the blood (55%) (92% water)
  • Cells (45%)
    • Erythrocytes are red blood cells. They are responsible for oxygen distribution.
    • Leukocytes are the white blood cells; they are responsible for “cleaning” the system of foreign invaders.
    • Thrombocytes or platelets are responsible for blood clotting
  • Serum is the liquid that separates from the blood when a clot is formed.
blood terminology
Blood Terminology
  • ABO blood groups—based on having an A, B, both or no antigens on red blood cells
  • Rh factor—may be present on red blood cells; positive if present and negative if not
  • Antigen—a substance that can stimulate the body to make antibodies. Certain antigens (proteins) found in the plasma of the red blood cell’s membrane account for blood type.
  • Antibody—a substance that reacts with an antigen
  • Agglutination—clumping of red blood cells; will result if blood types with different antigens are mixed
unknown stain at a scene
Unknown Stain at a Scene

Questions to be answered:

  • Is it blood?
  • Is it human blood?
  • Whose is it?
    • Determine blood type, alcohol content, drugs present
    • Determine the method(s) in which blood may have been deposited
presumptive tests for blood determination
Presumptive Tests forBlood Determination
  • Is: The generic term for any way of determining if a stain is blood.
  • Kastle-Meyer color test—a mixture of phenolphthalein and hydrogen peroxide; the hemoglobin will cause the formation of a deep pink color if blood is present
  • Hematest® tablet—reacts with the heme group in blood causing a blue-green color
  • Luminol test—reaction with blood to produce light
human vs animal blood
Human vs Animal Blood
  • Microscopic observation
  • Precipitin test—blood is injected into a rabbit; antibodies are formed; the rabbit’s blood is extracted as an antiserum; the antiserum is placed on sample blood. The sample will react with human proteins, if human blood is present. This test is very sensitive and requires only a small amount of blood.
animal blood
Animal Blood

Larger nucleic red blood cells

Frog Blood

human blood
Human Blood
  • Red blood cells are most numerous; 5 to 6 million per mm3
  • White blood cells are larger and less numerous; 5 to 10,000 per mm3
  • Platelets are tiny, cellular fragments; 350 to 500,00 per mm3
blood typing
Blood Typing
  • Blood type A has antigen A on the surface of the cell and will agglutinate with blood type B.
  • Blood type B has antigen B on the surface of the cell and will agglutinate with blood type A.
  • Blood type AB has antigens A and B on the surface of the cells and will not agglutinate with either type A or B blood.
  • Blood type O has neither antigen A or B and will not agglutinate.
  • The temperature used to break the antigen – antibody bond is 54C
blood typing1
Blood Typing

1901 Karl Landsteiner discovered the ABO blood groups.

1915 Leone Lattes developed a method of typing dried blood stains.

The procedure is called the absorption-elutionmethod, and dried blood spots are collected using a cotton swab moisten with distilled water.,

blood groups
Blood Groups

Can Give

Blood To

Can Get

Blood From

Antigen

Type

Antibody

A

A

B

A, AB

O, A

B, AB

O , B

B

B

A

Neither

A nor B

AB

A and B

AB

A, B, O, AB

Neither

A nor B

A, B, O, AB

O

A and B

O

let s say a piece of fabric is found with a blood stain on it
Let's say a piece of fabric is found with a blood­stain on it.

A small piece of the fabric is cut off

The fabric is then put in a small container of normal saline (a water solution with the same salt concentration as the human body), and a few drops of anti-A and anti-B antibodies are added.

slide17
The fabric is then removed and washed with normal saline, removing any antibodies not attached to the bloodstained fabric.

It is then placed in a container of freshsaline and heated to a temperature of 54°C for about 5 min.

This temperature is high enough to break the antibody-antigen bonds, and the antibodies are released into the saline solution.

Blood type can be determined

bloodstain pattern analysis

BLOODSTAIN PATTERN ANALYSIS

Based on the premise that all bloodstains and bloodstain patternsare characteristic of the forces that have created them.

blood spatter investigation
Blood Spatter Investigation
  • The success or failure of any criminal investigation often depends on the recognition of physical evidence left at a crime scene and the proper analysis of that evidence.
  • Crime scenes that involve bloodshed often contain a wealth of information in the form of bloodstains. The pattern, size, shape, and the location of such stains may be very useful in the reconstruction of the events that occurred.
bloodstain pattern analysis1
Bloodstain Pattern Analysis:
  • The examination of the shapes, locations, and distribution patterns of bloodstains, in order to provide an interpretation of the physical events which gave rise to their origin.
blood pattern reconstruction
Scene Pattern Reconstruction

1. Stain condition

2. Pattern

3. Distribution

4. Location

5. Directionality

Lab Results Reconstruction

1. Genetic marker typing

2. Age Determination

3. Source Determination

4. Race Determination

5. Sex Determination

Blood Pattern Reconstruction

—From “Cracking Cases” by Dr. Henry C. Lee

blood spatter evidence
Blood Spatter Evidence

A field of forensic investigation which deals with the physical properties of blood and and the patterns produced under different conditions as a result of various forces being applied to the blood. Blood, as a fluid, follows the laws of physics.

blood droplet characteristics
Blood Droplet Characteristics
  • A blood droplet will remain spherical in space until it collides with a surface
  • Once a blood droplet impacts a surface, a bloodstain is formed.
  • A droplet falling from the same height, hitting the same surface at the same angle, will produce a stain with the same basic shape.
  • How will the shape change as the height is increased or decreased?
blood droplet volume
Blood Droplet Volume
  • A droplet contains approximately 0.05 cc of fluid
  • Is not the same for all blood droplets, but is generally from 0.03 cc to 0.15 cc
  • Is directly dependent upon the surface or orifice from which it originates
  • The impact area is called the target.
conditions affecting shape of blood droplet
Conditions Affecting Shape of Blood Droplet
  • Size of the droplet
  • Angle of impact
  • Velocity at which the blood droplet left its origin
  • Height
  • Texture of the target surface
    • On clean glass or plastic—droplet will have smooth outside edges
    • On a rough surface—will produce scalloping on the edges
questions answered by blood spatter interpretation
Questions Answered by Blood Spatter Interpretation
  • The distance between the target surface and the origin of blood
  • The point(s) of origin of the blood
  • Movement and direction of a person or an object
  • The number of blows, shots, etc. causing the bloodshed and/or the dispersal of blood.
  • Type and direction of impact that produced the bloodshed
  • The position of the victim and/or object during bloodshed
  • Movement of the victim and/or object after bloodshed
bloodstain terminology
Bloodstain Terminology
  • Angle of impact—angle at which blood strikes a target surface.
  • Bloodstain transfer—when a bloody object comes into contact with a surface and leaves a patterned blood image on the surface
  • Backspatter—blood that is directed back toward the source of energy
  • Cast-off—blood that is thrown from an object in motion
bloodstain terminology1
Bloodstain Terminology
  • Contact stain—bloodstains caused by contact between a wet blood-bearing surface and a second surface which may or may not have blood on it
    • Transfer—an image is recognizable and may be identifiable with a particular object
    • Swipe—wet blood is transferred to a surface which did not have blood on it
    • Wipe—a non-blood bearing object moves through a wet bloodstain, altering the appearance of the original stain
bloodstain terminology2
Bloodstain Terminology
  • Directionality—relates to the direction a drop of blood traveled in space from its point of origin
  • Terminal velocity—the greatest speed to which a free falling drop of blood can accelerate in air. It is dependent upon the acceleration of gravity and the friction of the air against the blood—approximately 25.1 feet/second.
    • High velocity—greater than 25 feet per second, usually 100 feet per second; gives a fine mist appearance
    • Medium velocity—5 to 25 feet per second
    • Low velocity—5 feet per second or less
bloodstain patterns
Bloodstain Patterns

The shape of a blood drop:

  • Round—if it falls straight down at a 90 degree angle.
  • Elliptical—blood droplets elongate as the angle decreases from 90 to 0 degrees; the angle can be determined by the following formula:
impact
Impact
  • The more acute the angle of impact, the more elongated the stain.
  • 90 degree angles are perfectly round drops with 80 degree angles taking on a more elliptical shape.
  • At about 30 degrees the stain will begin to produce a tail.
  • The more acute the angle, the easier it is to determine the direction of travel.
bloodstain patterns1
Bloodstain Patterns
  • The harder and less porous the surface, the less the blood drop will break apart.
  • The softer and more porous the surface, the more a blood drop will break apart.
  • The pointed end of the blood stain faces the direction of travel.
area of intersection and convergence
Area of Intersectionand Convergence

The location of the blood source can be determined by drawing lines from the various blood droplets to the point where they intersect.

The area of convergence is the point of origin; the spot where the “blow” occurred. It may be established at the scene with measurement of angles by use of strings.

blood evidence
Blood Evidence
  • Class evidence for blood would include blood type. If you can determine the DNA you would have individual evidence.
  • Blood stain patterns are considered circumstantial evidence in a court room. Experts could argue many points including direction of travel, height of the perpetrator, position of the victim, left/right hand, whether the body was moved, etc.
secretors
Secretors

80% of the population are secretors. Their blood-type antigens are found in high concentration in their body fluids such as saliva, semen, vaginal secretions and gastric juice.

bloodstain pattern analysis2
Bloodstain Pattern Analysis:
  • The determinations made from bloodstain patterns at the scene or from the clothingof principals in a case can be used to:
  • Confirm or refute assumptions concerning events and their sequence:Position of victim. (standing, sitting, lying)Evidence of a struggle. (blood smears, blood trails)
  • Confirm or refute statements made by principals in the case:Are stain patterns on a suspects clothing consistent with his reported actions?Are stain patterns on a victim or at a scene consistent with accounts given by witnesses or the suspect?
transfer bloodstains
TRANSFER BLOODSTAINS
  • A transfer bloodstain is created when a wet, bloody surface comes in contact with a secondary surface.
  • A recognizable image of all or a portion of the original surface may be observed in the pattern,as in the case of a bloody hand or footwear
projected bloodstains
Projected bloodstains are created when an exposed blood source is subjected to an action or force, greater than the force of gravity.)The size, shape, and number of resulting stains will depend, primarily, on the amount of force utilized to strike the blood sourcePROJECTED BLOODSTAINS
cast off stains

Cast Off Stains

Blood released or thrown from a blood-bearing object in motion

impact spatter
Impact Spatter
  • Blood stain patterns created when a blood source receives a blow or force resulting in the random dispersion of smaller drops of blood.
low velocity
Gravitational pull up to5 feet/sec.

Relatively large stains4mm in size and greater

Usually result of blood dripping from person standing still, walking/running, or castoff

Usually around 90 degree angle

Low Velocity
medium velocity
Force of 5 to 25 feet/sec.

Preponderant stain size1 to 4mm in size

Often caused by blunt or sharp-force trauma ( knife, hatchet, club, fist, artery spurt

Medium Velocity
high velocity
Force of 100 feet/sec. andgreaterPreponderant stain size1mm in size and smaller Mist like appearance

Ex gunshot, coughing, sneezing or explosives

High Velocity
directionality of bloodstains
DIRECTIONALITY OF BLOODSTAINS
  • When a droplet of blood strikes a surface perpendicular (90 degrees) the resulting bloodstain will be circular.That being the length and width of the stain will be equal.
  • Blood that strikes a surface at an angle less than 90 degrees will be elongated or have a tear drop shape.Directionality is usually obvious as the pointed end of the bloodstain ( tail ) will alwayspoint in the direction
impact angle determination
IMPACT ANGLE DETERMINATION
  • ANGLE of IMPACTis the acute angle formed between the direction of the blood dropand the plane of the surface it strikes
slide53

By utilizing trigonometric functions its possible to determine the impact angle for any given blood dropletSin = length(mm)Width (mm)

saliva
Saliva :

Saliva is becoming more and more useful as physical evidence. In the past, it was mostly used to determine blood type.

saliva from a secretor can be used to determine their blood type.

Evidence such as cigarette butts, chewing gum, bite marks, envelopes, and stamps should be packaged in clean paper or a paper bag. If the evidence is damp, it should be air-dried before packaging. Saliva residues can be removed from immovable objects using a moistened cotton swab.

semen
SEMEN

In the case of sexual crimes one of the most important pieces of physical evidence for the investigator to discover is the presence of seminal fluid (semen)..

When the scene of a sexual crime is searched, it is customary to first try to locate any seminal stains.

slide56
This can be accomplished using ultraviolet (UV) light since seminal stains fluoresce under UV light.

Suspected stains can be tested using a piece of filter paper moist­ened with a solution of sodium naphthol phosphate or Fast Blue B. Both these chemicals change color on reacting with the acid phos­phatase present in fluid.

chapter 5 hair

Chapter 5:Hair

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

phone calls taper off.”

—Johnny Carson

Comedian and television host

introduction
Introduction

Human hair is one of the most frequently found pieces of evidence at the scene of a violent crime. It can provide a link between the criminal and the crime.

From hair one can determine:

If the source is 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

hair analyis

HAIR ANALYIS

HAIR IS A VERY PERSISTEN FORMOF PHYSICAL EVIDENCE

slide61
Hair is composed mostly of protein produced from the hair follicle.

The follicle is fed by tiny blood vessels

Hair can be used for drug analysis because anything present in the bloodstream is also incorporated into the hair.

The protein of the hair is keratinized, which makes it very strong.

components of hair
Components of Hair

Human hair has 3 layers called the cuticle, cortex and medulla.

The cuticle is the outermost layer of hair.

The cuticles of different species display different patterns.

Forensic scientist can analyze the cuticle pattern of any hairs left at the crime scene to determine answers.

hair shaft
Hair Shaft

Composed 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
The Cuticle

The cuticle is the outermost layer of hair which is covered with scales. The scales point toward the tip of the hair. Scales differ between species of animals and are named based on their appearance. The three basic patterns are:

Coronal

Spinous

Imbricate

three basic scale structures that make up the cuticle
three basic scale structures that make up the cuticle

spinous (petal-like)

(

imbricate (flattened)

coronal (crown-like)

human scales
Human Scales

In order to visualize the

Scales:

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 in

this slide?

the cortex
The Cortex

The cortex gives the hair its shape.

It has 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
The Medulla

The medulla is the hair core that is not always visible. The medulla comes in different types and patterns.

  • Types:
    • Intermittent or interrupted
    • Fragmented
    • Continuous
    • Stacked
    • Absent—not present
human medulla
Human Medulla

Human medulla may be continuous, fragmented or absent.

medullary index
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
Hair Shape

Can be straight, curly or kinky depending on the cross-section, which may be round, oval or crescent-shaped

Crescent moon

(Kinky)

Oval

(Curly)

Round

(Straight)

hair growth
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

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

the root
The Root

Human 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

hair comparison
Hair Comparison

Color

Length

Diameter

Distribution, shape and color intensity of pigment granules

Dyed hair has color in cuticle and cortex

Bleaching removes pigment and gives a yellow tint

Scale types

Presence or absence of medulla

Medullary type

Medullary pattern

Medullary index

Hair samples are matched using a comparison microscope

dna from hair
DNA from Hair

The root contains nuclear DNA. If the hair has been forcibly removed, some folicular tissue may be attached containing DNA.

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 costly than using nuclear DNA.

collection of hair
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
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.

caucasian hair
Caucasian Hair

This is a human head hair of Caucasian origin. Caucasian hairs come in the widest variety of colors, can be of fine to medium coarseness and are generally straight or wavy.

In addition, the shafts vary from round to oval in cross section. Finally, color pigments are fine- to medium-sized and are evenly distributed throughout the shaft

caucasian hair1
Caucasian hair

Photomicrograph of Caucasian Head Hair

Photomicrograph of Beard Hair Medulla (Doubled

african american
African American

This is a human head hair of Afro-Caribbean origin. Such hairs are generally curly or kinky, and have a flattened cross section.

Larger than those of other racial groups, its pigment particles are grouped in clumps of different sizes and shapes and may be so dense that they render the hair opaque.

Furthermore, the hair shaft may vary — or seem to vary — in diameter because of its flattened nature and the way it settles on the microscope slide.

slide82
Top right photo is hair with lice eggs, Bottom photo of recently cut hair(Left) and of a hair sample with split ends (
artificial treatment
Artificial treatment

Bleaching removes pigment from the hair and can give the hair a characteristic yellow cast

dyed hairs possess an unnatural cast or color. In addition, the cuticle will take on the color of the dye

asian hair sample
ASIAN HAIR SAMPLE

This is a human head hair of Asian origin.

Such hair is generally coarse, straight and circular in cross section. Its diameter is wider than the hair of other racial groups, and the outer layer of the hair, the cuticle, is usually significantly thicker.

The medulla, or inner layer of cells, is continuous and wide.

In addition, the hair shaft contains pigment particles that are generally larger than those of Caucasian hairs, and often appear to be grouped in patchy areas.

Finally, the hair may have a reddish appearance, a product of its pigment

animal vs human hair samples
Animal vs Human hair samples

Humans have a very fine cuticle pattern, called imbricate, with overlapping shingles of cuticles always point toward the tip.

Animal hair often has much rougher cuticles, such as spinous or coronal.

Spinous cuticle patterns are found on the hair of cats, minks, seal but not on humans.

Coronal cuticle patterns are found on the hair of rodents and bats

spinous or petal like scales
Spinous or petal-like scales

Spinous or petal-like scales are found at the proximal region of mink hairs and on the fur hairs of seals, cats, and some other animals

left is mink, below is seal

coronal crown like
coronal (crown-like),

Coronal scales are commonly found in the hairs of small rodents and bats but rarely in human hairs.

imbricate scales
Imbricate Scales

Lion Hair

The imbricate or flattened scales type consists of overlapping scales with narrow margins.

They are commonly found in human hairs and many animal hairs

deer hair
Deer hair

This is a deer hair. Unlike that of any other animal, the root of deer hair has a wine-glass shape: a narrow root that gradually widens.

In addition, the medulla, or inner layer of cells, consists of spherical cells that take up the whole width of the hair in a repeating pattern of different shapes, such as a hexagonal shape, depending on what member of the deer family the subject belongs to

cat hair
Cat Hair

This is a cat hair.

Cat hair has fibrous roots and its pigment particles do not run down to the root.

In addition, its medulla, or inner layer of cells, is thicker than that of dog hair

dog hair
Dog Hair

This is a dog hair.

Dog hair has spade-like roots and its pigmentation runs down throughout the shaft to the root.

Its medulla, or inner layer of cells, is thinner, too, than that of cat hair