Name
Block
Date
ScT 11: Blood and Blood Spatter
A) Introduction and History
Introduction - Blood can be used in two ways as evidence during an investigation: to extract DNA
for analysis or as physical evidence when blood spatter is studied.
 Blood typing can provide
; whereas DNA profiling
can provide individual evidence.
 A blood splatter pattern can give information about the
of an
account by a witness or a suspect.
 It also can provide information about the
the
of the blood,
and
of impact, and
used.
 Our understanding of blood began in ancient times and continues to grow today.
B) Blood Splatter
 Blood spatter has been used in investigative cases since 1894.
 In
the meaning of the splatter pattern was
first analyzed.
 When a wound is inflicted, a blood splatter pattern may be
created.
 It takes
to
make a blood splatter pattern.
 The pattern can help to reconstruct the events surrounding a shooting, stabbing, or beating.
C) Blood Splatter Analysis
Analysis of a splatter pattern can aid in determining the:
1.
4.
2.
5.
3.
–
Blood has a cohesive nature & the cells tend to remain tightly attracted to one another. So,
when dropped from
to ground form
droplets.
–
When blood falls from a height or at a high
velocity, it can overcome its natural cohesiveness and
form
–
.
When it falls onto a less-than-smooth surface, it
can form
around the drops.
D) Blood Splatter Analysis—Six Patterns
Describe each of these: Label each picture with the corresponding letter!
a. passive drops
b. arterial gushes
c. splashes
d. smears
e. trails
f. pools
E) Blood Splatter Analysis—Directionality
When a drop of blood is longer than it is wide, it’s possible to determine the angle it was traveling.
Cohesion:
Adhesion:
Surface Tension:
The shape of an individual drop of blood provides clues to the direction
from where the blood originated =
* This can be determined by measuring the
of the droplet.
How will the point of impact compare with the rest of a blood pattern?
F) Blood Splatter Analysis—Impact
G) Blood Splatter Analysis—Location of the Origin of the Blood
The location from which the blood originated (source) can be determined if there are at least two
blood spatters.
Lines of convergence


H) Crime Scene Investigation of Blood
Even after washing a room of visible blood, some blood evidence remains.
• A compound called Luminol will cause hemoglobin to fluoresce under black light.
• There are four steps in investigating blood left at a crime scene: confirm that the stain is blood,
confirm that the blood is human blood, determine the blood type, and perform a DNA analysis if
necessary and if DNA can be isolated from the sample. See checklist below:
1. Search for blood evidence.
A stain could be ketchup, red ink, or other red substance. MAKE SURE IT’S BLOOD BEFORE
YOU COLLECT IT!
– Kastle-Meyer Test =
– Leukomalachite Green =
2. If any is discovered, process it determining:
a.
b.
3. Interpret the findings:
a.
b.
c.