Question to be answered:
 Is it blood?
Light Source
Use a high-intensity light or UV lights
Leucomalachite test - a mixture of leucomalachite
green, acetic acid and distilled water is placed on
sample; then a drop of sodium perborate added will
turn blood a green-ish colour.
Is It blood?
Kastle-Meyer test a mixture of phenolphthalein and
hydrogen peroxide; the hemoglobin will cause the
formation of a deep pink colour if blood is present.
Kastle-Meyer Test
Video
• HemaStix is a strip that has been coated with
tetramethylbenzidine (TMB) and will produce a green
or blue-green colour with the presence of hemoglobin.
HemaStix
Luminol
Luminol
Reaction
Fluorescein
It is also capable of detecting latent or old blood, similar
to luminol. It may also react to many of the same things
as luminol (copper and bleach).
LCV or Leuco Crystal Violet
Fluorescein
Reaction in
UV Light
Question to be answered:
 Is it human blood?
Animal Blood
Larger nucleic red blood cells
Human blood vs Animal blood
 Microscopic observation
Frog Blood

Precipitin test - human blood is
injected into a rabbit;
• The sample will react with human
• Human antibodies are formed;
proteins, if human blood is
present.
• the rabbit’s blood is extracted
as an antiserum;
• This test is very sensitive and
• the antiserum is placed on
requires only a small amount of
sample blood.
blood.
Microscopic
Views
Fish Blood
Bird Blood
Horse Blood
Cat Blood
Dog Blood
Human Blood
Frog Blood
Snake Blood
Components of blood
7
Antigen determines blood type
Antibody
Rhesus Blood Types
Other proteins can distinguish blood (Rh, MN, etc.)
 85% of Caucasians, 94% of Black Americans and 99% of all Asians are
Rh positive.
 Antigen-Antivody reactions determine blood types

http://www.bloodservices.ca/centreapps/internet/uw_v502_mainengine.nsf/page/Percent
age-of-Blood-Types-In-Canada?OpenDocument
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Questions Answered by Bloodstain Pattern Analysis
The distance between the target surface and the origin of blood
Type and velocity of weapon
Number of blows
Handedness of assailant (right or left-handed)
Position and movements of the victim and assailant during and after the
attack
Which wounds were inflicted first
Type of injuries
How long ago the crime was committed
Whether death was immediate or delayed
Blood Droplet Characteristics
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.

Spatter – Bloodstains created from the application of force to the area
where the blood originated.
Origin/Source – The place from where the blood spatter came from or
originated.
Parent Drop –
Satellite Spatters
Satellite Spatters –
Spines
Spikes or Spines –
Parent Drop
Wipe - a non-blood bearing object moves through a wet bloodstain,
altering the appearance of the original stain
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
Medium velocity
Low velocity
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—
Cast-off—blood that is thrown from an object in motion
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
Conditions Affecting Shape of Blood Droplet

Passive Bloodstains

Projected Bloodstains

Transfer or Contact Bloodstains
There are six patterns that blood can form.
Describe each of these based on the images above:
1) Passive drops
4) Smears
2) Splashes
3) Arterial gushes
5) Trails
6) Pools
Stages of Impact
Stage 1: contact & collapse
Stage 3: dispersion
Stage 2: displacement
Stage 4: retraction
Effect of Target Surface

.
The harder and less porous
the surface, the less the blood
drop will break apart.
Spreads out smoothly

.
The softer and more porous
the surface, the more a blood
drop will break apart.
..
ST of spreading edge is
broken by irregular surface



Drip Pattern
Free-falling drops dripping into wet blood
Large irregular central stain
Small round & oval satellite stains
.
.
.
. ..
. .. . .
Impact at An Angle
Wave Cast-off
Tail of elongated stain
points in direction of travel
.
Tail of wave cast-off points
back to parent drop
Parent drop
wave cast-off
Height above point of convergence
Point of Origin
Origin
length
width
Angle of impact = arc sin W/L
85
60
45
Distance from point of convergence
30
Point of Convergence and Origin
The Point of Convergence:
The Point of Origin
Point of Convergence
Point of Origin
Tracing Origin of Bloodspots
 Point of convergence method
• 2 dimensional image


Point of origin method
• adds 3rd dimension to image
In practice:
• use of string & protractor at scene
• use of computer at laboratory



Low velocity (5 f/s, 1.5 m/s)
Medium velocity (25 - 100 f/s, 7.5 - 30 m/s)
High velocity (>100 f/s, 30 m/s)

Large central irregular area surrounded by elongated
peripheral spatter pattern
Patterns can help investigators determine the type of weapon used.
• What kind of a pattern is produced by a gun shot?
• What kind of a pattern is produced by a hammer blow?
Medium Velocity Blood Spatter
 Blood source subjected to MV impact
• (25 - 100 f/s, 7.5 - 30 m/s)
 Spot diameter: mostly 1 - 4 mm
6” ruler
Point of impact 15 cm
in front of vertical
target surface
Medium Impact
 Medium impact occurs when a force such as a bat is applied.
 The pointed end of the blood stain faces the direction of travel.
ceiling
Cast-off from Weapon
 Blood is cast-off tangentially to
arc of upswing or backswing
 Pattern & intensity depends on:
• type of weapon
• amount of blood adhering to
weapon
• length of arc
Medium velocity
 Blood exiting body under arterial pressure
 Large stains with downward flow on vertical surfaces
 Wave-form of pulsatile flow may be apparent

Blood source subjected to HV impact
• > 100 f/s, 30 m/s
 Fine mist: spot size < 0.1 mm
 Small mass limits spread to 1 m
 Some larger droplets reach further
 Gunshot
◦ back-spatter from entry wound
◦ forward spatter from exit wound
 High speed machinery

High impact - fine mist of droplets
Gunshot: back & forward spatter
Blood stained foam held just above target surface.
bullet exits foam
Bullet enters
foam
bullet
Back-spatter
on entry
Forward spatter
on exit
Bullet passing L to R just above sheet
Gunshot Back Spatter
 Arises from entrance wound
 Passes back towards weapon & shooter
 Seen only at close range of fire
 Seen on:
• inside of barrel
• exterior of weapon
• hand, arm, chest of shooter
Back spatter
on steadying hand
Flow Patterns
 Blood flows horizontally & vertically
 Altered by contours, obstacles
 Often ends in pool
Sperm

Males release 2.5 to 6 milliliters of seminal
fluid per ejaculation with approximately
100 million sperm per milliliter
400X
Determination of Seminal Fluid
 Acid phosphatase colour test
• The presence of acid phosphatase, the enzyme secreted by the
prostate gland into the seminal fluid, will turn purple when sodium
alpha naphthylphosphate and Fast Blue B solution are placed on it.
• It will also fluoresce under UV light when it comes in contact with 4methyl umbelliferyl phosphate.
Determination of Seminal Fluid
 Prostate Specific Antigen (PSA) or p30 – unique to seminal plasma
• P30 is isolated and injected into a rabbit where antibodies are
produced (anti-p30).
• The stain extract is place in one well of an electrophoresis plate and
the anti-p30 in the opposite well. The electric is applied and the
antigens and antibodies move toward each other. The formation of
a precipitation line between the wells shows the presence of p30 in
the sample stain. It, therefore, must be seminal fluid.
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.
Your Task:
Your group will create a bloody crime
scene for another group to analyze.
 HW: Write the scenario you will create
and how you will create it. Write down
how you will analyze the unknown blood
spatter from the other group.
 Bring: Garbage bag/old clothes, goggles,
protractor, tools and object to hit (wooden
block), calculator
