Forensic science

2. The practice of bloodletting began around 2500 B.C. with the
Egyptians to try to cure diseases. It continued with the Greeks and
Romans, the Arabs and Asians, then spread through Europe during the
Middle Ages and the Renaissance. It reached its peak in Europe in the
19th century but subsequently declined and today in Western medicine
is used only for a few select conditions.

3. 500 B.C. – Greeks distinguished between arteries and veins
• Arteries carry oxygenated blood from
the heart to various parts of the body
• Arteries have a thick, elastic muscle layer that
can handle high pressure of the pumping
blood.
• Veins carry deoxygenated blood
towards the heart
• Veins have a thin, elastic muscle layer with
valves that prevent the blood from flowing in
the opposite direction.

4. 1659 A.D. – Anton van Leeuwenhoek viewed blood cells under a microscope
1795 – First blood transfusion performed

5. 1901 – Karl Landsteiner discovered three blood types: A, B, O
1902 – Alfred Decastello discovered fourth blood type: AB

6. 1922 – Percy Oliver established the first blood donor service
1935 – Mayo Clinic developed a method to store blood for transfusions
1937 – Dr. Bernard Fantus established the first blood bank

7. 1940 – Karl Landsteiner discovered the Rh protein
Rh factor is also called "Rhesus factor"
because it was first discovered in the blood of
Rhesus monkeys (small monkeys from India
often used for experimentation).
Importance of Rh Factor
The Rh discovery had immediate practical importance because it
explained a relatively common medical disorder known as
erythroblastosis fetalis.
• Rh-negative women who become pregnant with an
Rh-positive fetus (an unborn child) sometimes develop
antibodies against the Rh factor in the fetus. Causes no
problem during the woman's first pregnancy, since the
number of antibodies produced tends to be small.
• Second pregnancy: this can result in complications such as
anemia, jaundice (a condition in which bile pigments build up
in the blood and cause skin, eyeballs and urine to take on a
sickly yellow tone) or premature birth.
Today, this reaction can be controlled by immunizing Rh negative
women after their first pregnancy with a drug known as RhoGam.
Video Clip

8. 1959 – First case of AIDS recorded in the Congo
1984 – Robert Gallo identified the virus causing AIDS
Video Clip
HIV (human immunodeficiency virus) is
a virus that attacks cells in the immune
system and destroys a type of white
blood cell called a T-helper cell, and
makes copies of itself inside these cells.
AIDS (acquired immune
deficiency syndrome) is a set
of symptoms caused by HIV. A
person is said to have AIDS
when their immune system is
too weak to fight off infection,
and they develop certain
defining symptoms and
illnesses. This is the last stage
of HIV, when the infection is
very advanced, and if left
untreated will lead to death.

9. 1985 – Development of ELISA test (enzyme-linked immunosorbent
assay) to screen for diseases such as HIV by detecting and measuring
antibodies in blood.
1987 – Scientists began developing blood-screening tests for infectious
diseases.

10. Blood can provide various evidence to investigators at a crime scene:
i. Blood spatter patterns can be used to reconstruct a
crime scene and show how an attack was made
i. Blood can connect an object with a crime (ex.
Discarded weapon)
i. Blood can connect a suspect
with a crime (ex. blood on
clothing) or place a suspect
at a crime scene
(ex. Criminal blood at scene)

11. Blood typing
is considered
class
evidence
and is good
to rule out
suspects.
DNA profiling from blood is
considered individual
evidence and can help
pinpoint a suspect.

12. • Blood is a tissue that circulates around
through the body.
• The average adult has about
10 pints of blood. (1.25 gallons)
• Blood is made of both cells
(45%) and Plasma (55%).

13. Blood cells are made in the bone marrow, the spongy
material in the center of the bones. The body will replenish the
elements given during a blood donation – some in a matter of hours and
others in a matter of weeks.

14. 3 kinds of cells which make up blood:
Red Blood Cells (RBCs )
1. RBCs are called
erythrocytes.
2. They have
hemoglobin and
carry oxygen and
carbon dioxide.
a. Hemoglobin is an
iron-containing
protein that binds
to oxygen and
gives blood its red
color.
3. They have no nucleus
and no nuclear DNA.

15. White Blood Cells (WBCs)
1. WBCs are called
leukocytes.
2. They are an immune
system cell which fight
disease and produce
antibodies.
3. They are the only blood
cells that contain DNA;
therefore they are the
only blood cell useful in
DNA profiling.
• The two most common
types are the
lymphocytes and
neutrophils

16. There are several types of White Blood Cells (WBCs)
a. The two most common types are the
lymphocytes and neutrophils.
i. Lymphocytes are made in lymphoid
tissue in the spleen, lymph nodes, and
thymus gland. Lymphocytes identify
foreign substances from germs (bacteria
or viruses) in the body and produce
antibodies and cells that specifically
target them.
ii. Neutrophils kill and digest bacteria and
fungi. They are the most numerous type
of white blood cell and your first line of
defense when infection strikes. They
move out of blood vessels into infected
tissue to attack the bacteria. Pus is made
up largely of neutrophils. Normally a
serious bacterial infection causes the
body to produce an increased number of
neutrophils, resulting in a higher than
normal white blood cell count.

17. Platelets are called thrombocytes
• They are small cell
fragments that assist in
blood clotting and repair
damaged blood vessels.

18. There are about one billion red blood cells in two to three
drops of blood. For every 600 red blood cells, there are
about 40 platelets and one white cell.

19. i. Plasma is made of 90% water. The other 10% are:
1. Dissolved proteins (antibodies, hormones, clotting
factors)
2. Nutrients (O2
, glucose, amino acids, salts, minerals)
3. Wastes (urea, CO2
)
yellowish liquid portion of blood

20. a. There are 3 main kinds of blood vessels.
• Arteries carry blood away from the heart. They divide
again and again, and eventually form very tiny vessels
called capillaries. Capillaries supply cells with nutrients
then remove wastes.
The capillaries
gradually join
up with one
another to
form large
vessels called
veins. Veins
carry blood
towards the
heart.

21. lumen

22. Blood Typing identifies the
presence or absence of particular
proteins embedded in the cell
a. It is quicker and less expensive than DNA profiling
i. Produces class evidence but can still link a suspect
to a crime scene or exclude a suspect
b. The presence or absence of cell-surface proteins
determines a person’s blood type.

23. A and B Proteins
i. A and B proteins called antigens are found on the
surface of some RBCs.
ii. If a person’s blood cells have A antigen proteins, they
have type A blood.
iii. If a person’s blood cells have B antigen proteins, they
have type B blood.
iv. If a person’s blood cells have both A and B antigen
proteins, they have type AB blood.
v. If a person’s blood cells have neither A nor B antigen
proteins, they have type O blood.

24. Rh antibody
test
Anti-B
antibody
test
Anti-A
antibody
test
• Perform an antigen test and
look for agglutination
(clumping).
Video Clip 2
Video Clip 1

25. Video Clip
39
12
4
45

26. • 85% of the population has an additional surface
protein called the Rh factor and therefore have
Rh positive blood.
• The other 15% lacks this protein and has what we
call Rh negative blood.
• Referred to as Rh because it was first discovered
in 1940 in Rhesus monkeys.

27. Antigens are found in red blood
cell (and foreign cell) membranes.
Antibodies are found in blood
plasma.
• When a foreign material enters your body, your immune system
launches an attack called an antigen-antibody response in which
WBCs called B-lymphocytes release antibodies to attack the foreign
substance.
• Antigens are foreign molecules or cells that react to antibodies.
• Viruses, bacteria, and the RBCs of someone with a different
blood type all have antigen proteins that can cause an
antigen-antibody response.
Video Clip

28. • Antibodies are Y-shaped proteins
secreted by white blood cells that
attach to antigens to destroy them.
a. People with blood type A have
only the A antigen on red cells
and have B antibody in the
plasma.
b. People with blood type B have
only the B antigen on red cells and
have A antibody in the plasma.
c. People with blood type AB have
both A and B antigens on red cells
but neither A nor B antibody in
the plasma.
d. People with blood type O have
neither A nor B antigens on red
cells but both A and B antibody
are in the plasma.

29. Blood typing is critical for blood
transfusions. If a person receives a blood
protein foreign to their body, antibodies
can cause the blood to clump which can
possibly lead to death.
1. The clumping of RBCs is called
agglutination.
2. Blood typing tests identify the presence
of A, B, and Rh surface proteins.
Universal
Donor
Universal
Recipient
Video Clip 1, 2

30. * Students should know what blood types individuals
with each blood type can donate blood safely to and
what types they can safely receive blood from.

31. Many other blood proteins have been identified. Examples include:
• Glycophorin Antigen M
• Glycophorin Antigen N
• Phosphoglucomutase (PGM)
• Adenylate kinase (AK)
• Adenosine deaminase (ADA)
• Esterase D (EsD)
• Glucose-6-phosphate dehydrogenase (G-6-PD)
• Polymorphic proteins: Group-specific
Components (Gc) and haptoglobins (Hp)
i. Some patients require a closer blood match than that
provided by the ABO positive/negative blood typing. For
example, sometimes if the donor and recipient are from the
same ethnic background the chance of a reaction can be
reduced.
There are more than 600 known antigens besides A and B.
By testing for more
blood proteins, the
probability of
uniqueness increases,
making blood evidence
more individualized.

32. i. A grouping of blood stains
constitutes a blood spatter
pattern.
ii. Patterns help to
reconstruct the events
surrounding shootings,
stabbings, beatings, etc.
iii. In 1939, Dr. Victor
Balthazard first researched
and analyzed spatter
patterns.

33. iv. The distribution, size and shape
of bloodstains on a victim, on a
suspect, or on the walls, floors,
ceilings, or on objects at the
scene can help reconstruct these
blood shedding events.

34. Analysis of a spatter pattern can help to determine:
1. direction blood traveled
2. angle of impact
3. point of origin of the blood
4. velocity of the blood
5. manner of death
Bloodstain pattern analysis can also help one evaluate the credibility
of statements provided by a witness, a victim, or a suspect.

35. Cohesion
1. Blood sticks together as it falls maintaining a
round shape.
2. Blood also resists flattening out when it falls on
a flat surface. Cohesion and surface tension
help it to maintain a curved shape.
The shape of an individual drop of blood can provide
important clues in an investigation
• When blood falls from a height, or at a high
velocity, it forms satellite droplets, small
secondary droplets around the main drop
• When blood falls onto a less-than-smooth
surface, the edges may have spikes or
extensions

36. 3. A 90-degree impact angle will yield a circular shape.
Blood striking an object at angles less than 90 degrees
produces a tear drop shape.
a. A circular drop of blood indicates a blood drop fell
straight down, without force. This is typical from a
dripping wound.

37. b. An elongated blood drop indicates blood was traveling
from a different direction when it landed.
i. The point of impact may appear darker and
wider than the rest of the drop, with a tail
pointing in the direction of the blood’s
movement.
ii. Smaller, secondary droplets may break off and
will land in front of the moving droplet of blood,
allowing scientists to determine direction of
spatter.

38. When there are two or more blood spatters a scientist can
draw lines of convergence that can pinpoint the location
of the blood source.

39. 1. Measuring the length and width of
blood drops and using trigonometry
allows us to determine an approximate
point of origin.
2. Only experienced analysts trained in
this technique should perform these
measurements.
3. Strings can be placed over blood drops
along the axes of the stains at the
calculated impact angles, and a
resulting point of origin can be
visualized in three dimensions.
angle of
impact =
the width of the bloodstain in mm
Use answer to figure
out the arc sin of
that number
(opposite
side/hypotenuse)
the length of the bloodstain in mm

41. Passive drops Arterial gushes Splashes
Smears Trails Pools
Splashes help show
position of victim
Smears – bleeding victim
touching walls or
furniture
Blood Trails – victim
moving from one place
to another
Blood Pools – victim
bleeds heavily
Passive fall (90o
angle
to floor)– circular
drops w/secondary
satellites

42. 1. Smear patterns from a large volume of blood, at least 0.5 ml, are often
distorted so much that further classification is not possible.
2. However, Transfer Patterns occur when a wet bloody surface contacts a
second unstained surface creating recognizable mirror image or at least
a recognizable portion of the original surface.
a. Swipe Pattern - the transfer of blood onto a surface not already
contaminated with blood. One side is usually feathered which
indicates the direction of travel.
i. One common pattern at scenes is a hair swipe - a long thin
fine line transfer.
b. Wipe Pattern - created when an object moves through blood that
has not completely dried and moves, removes, or otherwise alters
it.

43. 1. Arterial spurting usually occurs when an artery is damaged and
the blood spurts or gushes from the wound in large volume
pulses. It continues spurting as long as the heart continues
beating.
2. Large drops striking a vertical surface decelerate from air
resistance and produce a pattern without spines. The drops strike
the surface and then characteristically drip or run downward due
to their large volume.

44. d. Speed and velocity also impact blood spatter.
1.Generally, the higher the energy, the
greater the division and the finer the
spatter.
2.Generally, the lower the energy, the less the
division and the larger the spatter.

46. 1. The movement and the number of swings can often be documented by
examining the cast-off pattern.
a. The instruments range from hammers, bats, tools, and hands, to
just about anything that can be used as weapon – the only
requirement is that the object becomes blood-stained during
multiple impacts.
b. Cast off bloodstains also can result from multiple stabbings.
2. During a beating with an instrument which produces the bleeding,
blood will not normally collect on the surface of the instrument from
the first strike.

47. 4. On subsequent strikes at the same location, blood will adhere to the
instrument since it now strikes a blood source. When the instrument
is raised or swung backward, its movement allows small drops of
blood to be released from its surface.
a. Some of these small drops will strike a surface, often a ceiling, at a
90-degree impact angle.
b. As the instrument continues to swing backward, the movement
accelerates and additional blood droplets will be cast-off the surface of
the instrument. These drops will approximate a liner pattern.
c. The small drops will strike at increasing acute angles and become
elongated.

48. d.When the swing of this bloody instrument
is interrupted, the resulting patterns are
called “cessation cast-off.”

49. The field of bloodstain pattern analysis requires knowledge of
math, physics, biology and chemistry. Students in Criminology
and Criminal Justice learn about bloodstain pattern analysis in
forensic science classes or classes specifically on blood spatter.
But most analysts begin as law-enforcement officers who learn
on the job, acquire certifications and take courses, workshops
and seminars. Many train in bloodstain pattern (or blood
spatter) analysis through the International Association of
Bloodstain Pattern Analysis (IABPA). The IABPA developed
criteria for the Basic Bloodstain Pattern Analysis Course, an
introductory 40-hour course on the subject. Other
organizations, such as the International Association for
Identification (IAP), offer workshops and seminars as well as
advanced courses which lead to certification in blood spatter

50. a. Search for Blood
i. Don’t see any blood?
1. Even with the most thorough cleaning, blood leaves residue that
is difficult to remove.
2. Luminol powder mixed with hydrogen peroxide is able
to detect hemoglobin left behind by blood. Spray the area
and if blood is present it will luminesce for about 30 seconds.
3. Luminol reacts to old or new blood, however it
destroys the blood so it cannot be tested later.

51. The basic idea of luminol is to reveal
blood traces with a light-producing
chemical reaction between several
chemicals and hemoglobin.

52. ii. See blood?
1. If blood stains or drops are found, confirm they are in fact blood.
a. There are many chemicals to test for the presence of blood.
i. Kastle-Meyer Test- swab turns pink if blood is detected.
2. To be presented accurately and usefully in court, bloodstain evidence
must be recognized, documented, preserved, and correctly evaluated.
a. When possible, deliver blood or stained object to lab immediately.
b. If unable to deliver to the Laboratory, or if the object must be
mailed, allow the stain to air dry completely before packaging.
c. Blood that is in pools should be absorbed by a gauze pad and
allowed to air dry. After it dries it should be refrigerated or frozen as
soon as possible. Blood should be taken to the lab as quickly as
possible; delays beyond 48 hours may make the samples useless.
d. If not completely dry, label and roll in paper or place in a brown
paper bag or box and seal and label container. Place only one item
in each container. Do not use plastic containers.

53. Bird Blood
Cat Blood
Dog Blood
Fish Blood
Frog Blood
Snake Blood
Horse Blood
If blood is present, lab will need to
confirm it is human blood.
1. All mammals, except camels and llamas,
have circular, un-nucleated RBCs.
2. Animals that are not mammals (birds, fish,
etc.) have oval blood cells with a nucleus.

54. ELISA test uses antibodies that
react to human blood to tell if
mammal blood is from human.
However in rare cases, it can be
confused with chimpanzee and
gorilla blood.
ELISA is an abbreviation for
"enzyme-linked immunosorbent assay."
ELISA is a test
that detects
and measures
antibodies in
your blood.

55. RECAP OF STEPS:
1. Confirm the stain is
blood. (presumptive)
• Visualization with
Luminol
• Kastle-Meyer test
2. Confirm the stain is
human. (confirmatory)
• ELISA test
3. If human, try to
determine whose
blood it is. First
determine blood type.
• Antibody test
4. If individual
information is needed,
then do DNA analysis.
(We will discuss DNA
tests in the next chapter)
Note: DNA is considered individualization,
not confirmatory.
Video Clip

56. Presumptive tests
• Can establish the possibility that a specific
bodily tissue or fluid is present
• Ex. Kastle Meyer Test or Luminol
Confirmatory tests
• Can identify a specific biological material
• Ex. ELISA Test, RSID Test for Human Blood,
or ABA Card Hematrace
Positive Negative

57. * Students should know what blood types individuals
with each blood type can donate blood safely to and
what types they can safely receive blood from.