forensic science

1. sAMHIGGINBOTTOMuniversityofagriculture,TECHNOLOGYAND
sCiences
GROUPPROJECT on bloodpattern analyses
GROUP-4
SUbmitted by- ADVISER- DR. LUV KESARWANI
Tanya gupta 17bslscfs014
Uttkarsh singh 17bslscfs011
Avaneesh kr. Singh 17bslscfs008
6 semester LSCFS

2. ACKNOWLEDGMENT
This presentation is on BLOOD PATTERN ANALYSIS. We are thankful to
our advisor Dr.LUV KESARWANI (Department of forensic science) for
his invaluable guidance and assistance,without whom our
accomplishments of the task would have not been possible.
We extend our sincere thanks to Dr. POONAM PRAKASH for her
cooperation during this project work.
GROUP 4
AVANEESH KR. SINGH (17bslscfs008)
UTTKARSH SINGH (17bslscfs011)
TANYA GUPTA (17bslscfs014)

3. INDEX
• BLOOD
• PROPERTIES OF BLOOD
• PHYSICAL PROPERTIES OF BLOOD
• INTRODUCTION OF BLOOD PATTERN ANALYSIS
• HISTORY
• INJURIES,DEATH &BLOOD
• PURPOSE OF BLOOD PATTERN ANALYSIS
• PRINCIPLES OF BLOOD PATTERN ANALYSIS
• CATEGORIES OF BLOOD PATTERN
• IMPACT SPATTER & ITS CLASSIFICATIONS
• INTERPRETING BLOOD PATTERNS
• TARGET SURFACE TEXTURE
• DIRECTIONALITY OF BLOODSTAINS
• DETERMINATION OF ANGLE OF IMPACT
• VOID PATTERNS
• DETERMINATION OF POINT OF CONVERGENCE
• DETERMINATION OF POINT OF ORIGIN
• DOCUMENTATION OF BLOOD STAIN EVIDENCE

4. BLOOD
Blood is a body fluid in humans and other animals that delivers
necessary substances such as nutrients and oxygen to the cells
and transports metabolic waste products away from those same
cells.
Blood is composed of 4 main components:–
• RED BLOOD CELLS –by volume,constitute 45% of the whole
blood.
• PLASMA –constitutes 54.3% of the whole blood.
• WHITE BLOOD CELLS-constitutes 0.7% of the whole blood.
• PLATELETS- normal count is 150,000-350,000 per micro liter of
blood.

5. PROPERTIES OF BLOOD
• 8% of total body weight.
• 5-6 liters of blood for males
• 4-5 liters of blood for females
• 40% of blood volume loss , internally or externally required
to produce death.
• 1.5L loss will cause incapacitation.
• A cut vein or artery will result in a loss of 0.5L per minute.

6. PHYSICAL PROPERTIES OF BLOOD
Once blood has left the body it behaves as a fluid and
laws of physics applies on it.
The laws are :-
•GRAVITY
•VISCOSITY
•SURFACE TENSION

7. BLOODPATTERN
ANALYSIS

8. INTRODUCTION
• Blood pattern analysis is the examination of the shapes,
location and distribution patterns of bloodstains, in order
to provide an interpretation of the physical events which
gives rise to their origin.
• Blood is the most significant and frequently encountered
type of physical evidence in forensic investigation of death
and violent crimes.
• Blood is studied by forensic pathologist to assist with the
diagnosis of various diseases that may relate to the cause of
death such as AIDS,anemia,leukaemia or malaria etc.

9. HISTORY
• Dr.Edward Piotrowski ,assistant at the institute of
forensic medicine at Poland,published first paper on
blood spattering in 1895.
• It was followed by French scientist Dr. Victor
Balthazard.
• Most profound work was done by professor Herbert
Leon MacDonell who had three publications and
several books written on blood spattering from 1971
to 1982.

10. INJURIES,DEATH & BLOOD
• Dead people do not bleed.
• If a body part is struck with an object the first blow will not
cause blood spatter.
• Blood Spatter occurs after the first blow when the wound
begins to bleed.

11. PURPOSE OF BLOOD PATTERN ANALYSIS
Blood pattern analysis helps in reconstruction of crime scene and is
required to determine the following:–
• Origin of the bloodstains
• Distance between target surface and origin at time of bloodshed
• Type and direction of impact that produced bloodstains.
• Object that produced particular bloodstain pattern.
• Number of blows,shots,etc, that occurred.
• Position of victim,assailant,or object during bloodshed.
• Movement and direction of victim,assailant,or object after
bloodshed.
• Additional criteria for estimation of time of death.

12. PRINCIPLES OF BLOOD PATTERN
ANALYSIS
Blood behaves according to certain scientific principles,
bloodpattern analysts can examine blood evidence left
behind and reconstruct the crime scene to recognise and
interpret patterns to determine how those patterns were
created
Blood can leave the body in many ways ,depending on the
type of injury inflicted.

13. CATEGORIES OF BLOODSTAIN PATTERNS
1. PASSIVE BLOODSTAINS
2. TRANSFER BLOODSTAINS
3. PROJECTED BLOODSTAINS

14. 1. PASSIVE BLOODSTAINS
• Passive bloodstains are drops created or formed by the force
of gravity acting alone.
• Categories of passive bloodstains are:-
• DROPS
• DRIP PATTERNS
• POOLS
• CLOTS

16. 2. TRANSFER BLOODSTAINS
• A transfer bloodstain is created when a wet,bloody surface
comes in contact with a secondary surface.
• Categories of transfer bloodstains are:-
• CONTACT BLEEDING
• SWIPE OR SMEAR
• WIPE
• SMUDGE

18. 3. PROJECTED BLOODSTAINS
• Projected or impact 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 utilised to
strike the blood source.

19. 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.

20. CLASSIFYING SPATTER BY VELOCITY
There are three basic categories of stain groups based on the
size of the bloodstain compared with the amount of force
propelling that bloodstain.
They are-
• LOW VELOCITY BLOODSTAINS
• MEDIUM VELOCITY BLOODSTAINS
• HIGH VELOCITY BLOODSTAINS

21. • LOW VELOCITY IMPACT BLOODSPATTER
Low-velocity is considered to be a force or energy equivalent to
normal gravitational pull up to a force or energy of 5 ft. /s (5 ft.
per second). The resulting stain is relatively large, usually 4
mm. in diameter or greater. Free-falling drops of blood affected
only by gravity.
EXAMPLE- This spatter often occurs
after an injury.

23. • MEDIUM VELOCITY IMPACT BLOODSPATTER
Medium-velocity is considered when a source of blood is
subjected to a force from 5 to 25 ft. per second. The resulting
stains range from 1 to 4 mm. in diameter.
EXAMPLE-These type of stains are
usually associated with beating or
stabbing.

24. • HIGH VELOCITY IMPACT BLOOD
SPATTER
High-velocity bloodstains are created when the source of
blood is subjected to a force with a velocity greater than 100
ft. per second. The resulting stain is predominantly less than
1 mm. in diameter although smaller and larger stains may be
observed.They take on a mist like
appearance.
EXAMPLE:-These types of stains are
usually associated with gunshot
injuries.

25. • BACK SPATTER- Blood
directed back towards the
source of energy or force
that caused the spatter.
Often lands on the weapon
or perpetrator.
• FORWARD SPATTER –blood
associated with an exit
wound.
CLASSIFYING SPATTER BY MECHANISM

26. 1 ARTERIAL SPURT/GUSH
Bloodstain patterns resulting from
blood exiting the body under
pressure from a breached artery.
CLASSIFYING SPATTER BY PROJECTION

27. 2.Cast-off stains:
Blood that has been
thrown from a secondary
object (weapon or hand)
onto a target other than
the impact site. Counting
the arcs can also show
the minimum number of
blows delivered.

28. 3.Expiratory
bloodspatter:
Blood which is spattered
onto a target, as a result of
breathing. this occurs
when an injury is
sustained to the throat,
mouth or airway.It tends
to form a very fine mist
due to the pressure
exerted by the lungs
moving air out of the
body.

29. INTERPRETING BLOOD PATTERNS
FOR ANALYSIS
When blood is impacted,droplets are dispersed through the
air. When they strike a surface,the shape of the stain changes
depending on the following :-
• angle of impact
• velocity
• distance of travel
• Type of the surface impacted

30. TARGET SURFACE TEXTURE
• Blood drops that strikes a hard smooth surface,like
glass,will have little or no distortion around the
edges.
• Blood drops that strikes linoleum flooring take on a
slightly different appearance.
• Blood drops that strikes wood or concrete are
distorted to a larger extent.the spines and secondary
spatter is present.

32. DIRECTIONALITY OF
BLOODSTAINS
• When a droplet of blood strikes a
surface perpendicular to resulting
bloodstain will be circular.
• Blood that strikes a surface at an
angle less than 90 degrees will be
elongated or have a tear drop shape.
• Directionality is obvious as the
pointed end of the bloodstain will
always point in the direction of travel.

33. IDENTIFICATION OF BLOODSTAIN FOR
DIRECTION DETERMINATION
To distinguish directionality,first identify the stain as:-
• PARENT STAIN- The main stain from which satellite spatter
originates.The tail of parent stain always point away from the
origin.
• RICOCKET STAIN- Blood that impacts a secondary object and then
bounce of falls to another target.
• SATELLITE STAIN- Small stains created when droplets detach from
a parent drop as its impacts a target.

37. DETERMINATION OF ANGLE OF IMPACT
• It is the acute angle formed between the direction of the
blood drop and the plane of the surface it strikes.

39. VOID PATTERNS
A void pattern occurs when a
person or object blocks the
path of the blood.They are
important as they show the
investigator if the object is
missing from the crime
scene.Void patterns are useful
for establishing the position
of victim and assailant within
the scene.

40. POINT OF CONVERGENCE DETERMINATION
•The common point ,on the 2D surface,over which
the directionality of several bloodstains can be
retracted.
•Once the directionality of a group of stains has
been determined,it’s possible to determine a 2D
point or area for the group of stains.

42. POINT OF ORIGIN DETERMINATION
•POINT OF ORIGIN:- is the location from which the
blood that produced the blood stain originated.
• It can be constructed graphically by plotting the
distance from the point of convergence with their
angle of impact on target surface.

44. DOCUMENTATION OF BLOOD STAIN
EVIDENCE
Since bloodstain pattern cannot be carried to the laboratory,
so care in documenting the scene is of utmost importance.
Photographs and detailed sketches drawn to scale are
invaluable part of the forensic report. Services of forensic
expert, well trained in bloodstain pattern analysis may be
utilized for scientific interpretation of stains in the context of
the crime.

45. THANK YOU