Transcript Blood & physiological Fluid Evidence

Drill
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Why is blood typing a class evidence?
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How is forensics biology different from
forensics serology?
Drill
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Define whole blood.
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What are the formed
elements of blood?
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Objective(s)
Explain and do a Blood
Spatter analysis.
Collection, Preservation &
Packaging of Biological
Evidence
Drill
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Define antibodies & antigens. How are
they different?
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Name two things that can be determine
from a blood splatter pattern.
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Name & describe 3 out of the 6 splatter
patterns.
Blood & Physiological Fluid
Evidence
Chapter 8 Blood and
Blood Splatter
 explain the composition of blood
 describe the function of blood cells
 determine the blood type of a blood
sample
 conduct a blood splatter analysis
 examine wounds and describe the nature
of the weapon
 find and process blood evidence
Introduction and History
 Blood typing can provide ______________;
whereas DNA profiling can provide
________________________.
 A _______________pattern can give
information about the truthfulness of an
account by a witness or a suspect.
 It also can provide information about the
______________ of the blood, the angle and
velocity of impact, and type of weapon used.
 Our understanding of blood began in
_______ times and continues to grow today.
Forensics biology
Preliminary examination of biological
evidence in blood transfer and sexual
assault cases, much that goes on the
___________________________.
Forensics Serology –
Preliminary examination and genetic typing
of biological evidence in blood transfer
and sexual assault cases
________________analysis was available.
Review
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What is the difference between forensics
biology and forensics serology?
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What kind of evidence can blood typing
provide for court?
Nature of Blood
1. Only _________________ tissue in the body.
2. Made up of several cell types;
________________(erythrocytes)
__________(leukocytes), and __________.
3. _______________ – blood serum protein
4. _______________________ - antibodies
Composition of Blood
 _______________carries cells and plasma—
the fluid with hormones, clotting factors, and
nutrients.
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________________carry oxygen to the
body’s cells and carbon dioxide away.
 _________________fight disease and
foreign invaders and, alone, contain cell nuclei.
 ______________ aid in blood clotting and the
repair of damaged blood vessels.
Function
1. ________________________through out the body.
2. Transfers _________________ throughout the body.
3. _________________.
4. ____________________
Amount of cells in blood
______ million RBC per cubic millimeter
____________ WBC per cubic millimeter
___________ mg/mL albumin
___________ mg/mL Immunoglobulin's
Review
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Name two functions of blood?
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What are the parts of blood with their
function?
1.
Tube of blood is drawn and allowed
to ______ for a few minutes for
________________.
2.
Blood will ____________ and
become a dark red and fall to the
bottom.
3.
_______ is on _____ is yellowish
and contains dissolved proteins and
other compounds.
4.
________ – same as serum but
contains the clotting protein.
Blood Typing—Proteins
42%
12%
3%
43%
of the population in the United States (of which 85% is
Rh+)
Blood typing is _________ and less expensive than
DNA profiling.
It produces class evidence but can still link a suspect to
a crime scene or exclude a suspect.
Review
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What are the four blood types for
humans?
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Which type is most common?
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Can a blood type convict a suspect?
Blood Typing—Antibodies; Additional
Proteins and Enzymes
 ____________ are proteins secreted by white
blood cells that attach to antigens to destroy
them.
 ____________ are foreign molecules or cells
that react to antibodies.
 ____________ are complex proteins that
catalyze different biochemical reactions.
 Many enzymes and proteins have been found in
the blood that are important for identification
purposes.
Blood Typing—Probability and
Blood Types
 Given the frequency of different genes within a
population, it is possible to determine the
probability that a particular blood type will
appear in a _____________________________.
 To determine the probability of two separate
events, it is necessary to multiply their individual
probabilities.
 By identifying the additional proteins in the
blood evidence sample, investigators can limit
the size of a suspect population and help identify
a suspect.
Blood Splatter
 In 1939 the meaning of the splatter
pattern was first analyzed.
 When a wound is inflicted, a blood
_____________ pattern may be created.
 It takes a _____________ of blood stains
to make a blood splatter pattern.
 The pattern can help to
_______________the events
surrounding a shooting, stabbing, or
beating.
Blood Splatter Analysis
Analysis of a splatter pattern can aid in
determining the:
________________________________.
________________________________.
________________________________.
________________________________.
Blood Splatter Analysis
 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.
Blood Splatter Analysis—Six
Patterns
Describe each of these:
a. ______________
b. ______________
c. ______________
d. ______________
e. ______________
f. ______________
Blood Splatter Analysis—
Impact
Patterns can help investigators determine the
___________________ 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?
Blood Splatter Analysis—
Directionality
The _________________ of an individual
drop of blood provides clues to the
direction from where the blood originated.
How will the point of impact compare
with the rest of a blood pattern?
Blood Splatter
Analysis—Location of the Origin
of the Blood
Draw straight lines down the axis of the
blood splatters.
 Where the ____________________, the
blood originated.
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Review
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1. How can blood splatter determine
direction?
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2. How can blood splatter determine
location/origin of the blood source?
Crime Scene Investigation
of Blood
1. Search for blood evidence.
2. If any is discovered, process it determining:
a. Whether the evidence is ____________.
b. Whether the blood is _________________.
c. The blood ___________________.
3. Interpret the findings:
a. See if the blood type matches a ________.
b. If it does not,_____________that suspect.
c. If it does, decide if ___________is needed
Collection, Preservation &
Packaging of Biological Evidence
__________________, Exemplar, Reference
are known sources of biological evidence.
Collected in a ___________________.
The ______ of the stopper is an indicator of
the _________ used.
_______ is most common
(enediaminetetraaceitic acia) in a purple
top.
Can get DNA from many other places;
Cheek (Buccal)
Review
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How is a known control different from an
alternative control?
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Why is a blank control used?
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Name 2 out a 3 guidelines for crime scene
investigation.
Biological Evidence from Scenes
_______ items with blood.
Fresh or Wet – clean spoonlike utensil.
Dried – Cutting, swabbing, scrapping, and elution
(dissolving).
Ensuring that the evidence is ___________________before
it is package and stored in a dry cool place.
Package in paper containers that can “___________”,
never is an air tight container.
Testing
___________________– specimen from a
known source.
_____________________– specimen
obtained that might be the source of
evidence.
_____________________– a clean sample
containing no specimen.
Forensics Identification of Blood
________________(Screening) - for
screening specimens that might contain
substances or materials.
False-positives or false-negative
Ideally preliminary test should give a
_________ false negatives to ________
this test as a screening tool.
Testing
______________________– A sample of
material on which biological evidence is
deposited.
___________________ – unintended or
potentially unrecognized, biological
material in or on biological evidence,
which could cause difficulty in interpreting
the results.
Forensics Identification of Blood
__________________–
More complicated and requires more time than a
preliminary test.
Entirely specific for the substance or material for which
they are intended.
A positive confirmatory means it is unequivocal
demonstration that the specimen contains the substance
or material.
No confirmatory test is available for blood – most the
analyst can say is “might or could have”.
Forensics Identification of Body
Fluids
Semen
Male reproductive
fluid.
Spermatozoa – ______
________ million
sperm per milliliter.
Seminal Plasma fluid
that suspends sperm.
Semen is associated with sexual
assault cases.
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Somewhere in America, a woman is raped every ____ minutes,
according to the U.S. Department of Justice.
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In 1995, _______ women were the victims of a rape or sexual
assault. (NationalCrime Victimization Survey. Bureau of Justice
Statistics, U.S. Department of Justice, 1996.)
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Over the last two years, more than _________ women were the
victim of a rape or sexual assault. (National Crime Victimization
Survey. Bureau of Justice Statistics, U.S.Department of Justice,
1996.)
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The FBI estimates that ____ of every _____________ females in
the United States were raped last year. (Federal Bureau of
Investigation, Uniform Crime Statistics, 1996.)
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Approximately______ of victims are raped by
husbands or boyfriends, _____ by
acquaintances, and _____ by other relatives.
(Violence against Women, Bureau of Justice
Statistics, U.S. Dept. of Justice, 1994)
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The FBI estimates that only ______ of all rapes
are reported to the police. U.S. Justice
Department statistics are even lower, with only
_________ of all rapes or attempted rapes being
reported to law enforcement officials.
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____ of every ____ rapes take place in a public area or
in a parking garage.
_____ of female victims reported that the offender was a
stranger.
_____ of rapes occur between the hours of ___ p.m.
and ____ a.m.
At ______of rapists were under the influence of alcohol
or drugs.
In _____of rapes, the offender used a weapon.
In _____of rapes, the victim sustained injuries other
than rape injuries.
______ of female rape victims require medical care after
the attack.
Semen shines fluoresce brightly when
exposed to ________.
Preliminary & confirmatory test for semen
stains – same as blood testing.
______________________________is a
color test for the enzyme produced by the
male prostate gland.
Evidence collection and sexual
assault cases
Rape Kits
Investigation
DNA profiling
Cases often succeed or fail on the
__________ of the parties, since there is
rarely a witnesses.
Injuries are properly _______________ and
helpful in some cases.
Identification of Saliva and Urine
Saliva is produced by three gland that empty into
the mouth cavity that contain a large amount of
_________.
Tests for amylase
Dyed starch
Radial enzyme diffusion
____________ is found in many plants and
animals, therefore it is not confirmatory only
indicative.
__________ – contains several substance in
large quantities.
Many animals produce urine, therefore it is
considered the same as saliva.
. . . . . . . . . . . . . . . . . Summary
 Blood consists of cellular components and plasma.
 The various human blood types are caused by the
presence or absence of A or B or both A and B
proteins on the surface of red blood cells.
 Blood splatter evidence can be used to recreate a
crime scene.
 Investigators endeavor to (a) locate, (b) identify,
and (c) interpret blood splatter patterns at crime
scenes.