Module 1 discussion
Based on this week’s readings, why is blood such a unique
fluid to study? How has the history of blood used as an investigative tool been
central to biological evidence collection?
Module 2 discussion
According to Dr. Pacheco (personal communication, April 16,
2010), the Phenolphthalein (or KM) test is so sensitive and specific to blood
that it can be used simply as a confirmation that blood is present. What effect
does this have on using other presumptive tests (such as those discussed in the
course) on crime scene evidence? Using your text and online resources, provide
an argument for or against using KM as a confirmation for blood at the scene.
Module 3 discussion
Based on this week’s readings, bloodstain evidence is very important
in crime scene investigation. Is it possible that phrasing the discipline as
bloodstain analysis instead of bloodstain interpretation would appear more
scientifically rigorous when testifying in a judicial setting? If not, why? Is
there a difference between bloodstain analysis and bloodstain interpretation?
Module 4 discussion
Read the following scenario. You arrive at the crime scene
of a death investigation. In the field are two homicide detectives, as well as
the EMT unit working on one of the victims. The deceased victim is on the
ground with a reddish-brownish substance on his clothing as well as a whitish
fluid protruding from the mouth. You are asked to process this scene. Do you
detect any biological hazards present? If so, what are they? How would you
protect yourself and any evidence that may be found? For your responses to
classmates, critique their rationale and try to poke holes in their protocol.
Module 5 discussion
What are your thoughts about the value of an autopsy? What
impact does it have on the criminal justice system? How does the core value of
Respect apply to autopsy proceedings? Should an autopsy always be performed?
What is the protocol for autopsy investigations in your state?
Module 6 discussion
As biological evidence most often is recognized by the media
and the public as “DNA,” what would you argue is the most common form of
biological material collected at a crime scene? Since DNA is technically not
what is collected (instead a swab of a fluid such as blood, saliva, sweat, or
semen), how important is the collection process for biological evidence? How
does Saint Leo’s core value of Integrity tie into biological evidence
collection?
Module 7 discussion
Where do you see the role of DNA in forensic investigations
heading in the future? Why should DNA continue to be the best standard of
evidence collected at a crime scene? Should DNA (and therefore, bodily fluid
evidence) cancel out all other types of crime scene evidence? Why or why not?
Module 8 discussion
The idea that DNA can either convict or exonerate
individuals based on whether their genetic material was found at a crime scene
has created some controversy. In your opinion, are the methods of collecting
DNA not stringent enough, creating opportunities for overturned convictions of
faulty DNA evidence? Why or why not? Support your position with information
from your text or other resources.
Module 2 Experiment A
Experiment A: Presumptive Blood Testing
The purpose of this lab is to give you practical experience
in the method of applying various presumptive
blood testing kits to suspected stains. Based on the
reactions you observe, you will be able to categorize
each stain as one of the following:
a) One that indicates blood may be present (a positive reaction);
b) One that gives no indication for the presence of blood (a
negative reaction); and
c) One that gives a false-positive reaction.
Upon completion of the experiments, you will record the
outcome of each in the results chart below and
as well as a two-page report documenting your observations
and whether the tests were effective. Submit
the assignment to the Dropbox and Turnitin.com no later than
Sunday 11:59 PM EST/EDT.
Caution! The following presumptive chemicals can be
dangerous. Please follow all safety
instructions and/or MSDS information. These chemicals should
not be swallowed or inhaled; they
may also damage or stain clothing.
Supplies from your CRM343 bodily fluids kit:
Phenolphthalein (KM) reagent presumptive test kit
Tetramethylbenzidine (TMB) reagent presumptive test kit
Leucocrystal violet (LCV) reagent presumptive test kit
Synthetic blood sample (1)
Cotton tip swab/applicators
Gloves
Face mask
Supplies from home:
Red craft paint
Fresh mashed potato (with skin)
Cooked tomato sauce
Red food coloring
Fresh raw beet juice
Remember that all of these tests are a multi-step process,
with a waiting period between steps to allow
for a false-positive to occur (if it is going to). Make
certain you read the instructions first before beginning
the testing process to understand how each test will work.
You can refer back to the textbook for a quick
primer on why presumptive tests are conducted.
NOTE: While you may not have enough of the reagents in your
criminalistics kit to do so, on the job
training will advise that you should always test the
reagents before using the test on the evidence.
These tests have a reagent and hydrogen peroxide, an oxidant
that gives off a free-radical oxygen in the
presence of the heme portion of blood. Most likely, a false
positive would occur between the reagent
being applied and the hydrogen peroxide being applied.
Tips
Avoid cross contamination! Do not touch the dropper bottle
tips to the swabs at any time. Do
not use the same swab on different samples.
Do not apply the reagents directly onto the evidence or onto
the swab which you are holding over
the evidence; you could potentially contaminate the evidence
if the reagents should drip from the
swab tip.
If needed, use de-ionized or distilled water to moisten the
swab tip in order to better transfer
some of the suspect stain.
Normally, when deciding which item/area to test, it is
generally best to test a peripheral area of
the stain. This allows the main (or concentrated) area of
the stain to remain undisturbed for any
future lab testing.
If you want to “save” or store your test swabs, you can use
the swab boxes contained in
your criminalistics kit to preserve the samples. Over time,
exposure to ambient air will
discolor the swabs.
Phenolpthalein (KM) presumptive pest kit instructions:
Use the known bloodstain control card to test the reagents
prior to testing the evidence stains.
Ideally, this control test should yield a positive reaction
and is called a positive control.
o To conduct the positive control test, you will follow the
directions below, getting the listed
result. Then you would repeat these steps to conduct the
actual presumptive tests on the
samples listed in the chart.
First, use a cotton tip swab to “retrieve” a sample of the
suspected reddish stained sample. If the
sample stain is dry, you can moisten the cotton tip swab
with the distilled water from your kit.
Then, add one drop of alcohol to the swab with the suspected
stain. Remember to not add the
reagent to the swab over the evidence; twist to the side as
you squeeze a drop of the reagent
onto the swab tip.
o Observe any color changes. If you get a pinkish color
developing on the swab tip, you
might have a contaminated reagent.
Next, add a drop of the phenolphthalein reagent to the swab
tip ~ it may be necessary to clear the
first drops from the reagent bottle to remove any oxidized
solution from the tip.
o Observe any color changes. If you get a pinkish color
developing on the swab tip, you
might have a false positive result or “bad” test.
Finally, add one drop of hydrogen peroxide to the swab tip.
o Blood is most likely present/indicated if a bright pink
color is observed within several
seconds. If a pink color develops after the addition of the
phenolphthalein reagent but
before the addition of the hydrogen peroxide, this indicates
that a contaminant is present
and the test should be considered invalid.
o The possibility also exists that you can have a false
negative result, meaning that blood
was actually present in the sample but the concentration may
be diluted or compromised,
thus not producing a color reaction.
Note It is suggested that an area adjacent to the sampled
evidence stain be tested using the
same procedure described above. This test should yield a
negative reaction and is called a
negative control.
Leucocrystal Violet (LCV) presumptive pest kit instructions:
Use the known bloodstain control card to test the reagents
prior to testing the evidence stains.
Ideally, this control test should yield a positive reaction
and is called a positive control.
o To conduct the positive control test, you will follow the
directions below, getting the listed
result. Then you would repeat these steps to conduct the
actual presumptive tests on the
samples listed in the chart.
First, use a cotton tip swab to “retrieve” a sample of the
suspected reddish stained sample. If the
sample stain is dry, you can moisten the cotton tip swab
with the distilled water from your kit
Then, add one drop of LCV reagent to the swab with the
suspected stain. Remember to not add
the reagent to the swab over the evidence; twist to the side
as you squeeze a drop of the reagent
onto the swab tip.
o If a bright blue/purplish color develops after the
addition of the LCV reagent but before
the addition of the hydrogen peroxide, this indicates that a
contaminant is present and the
test should be considered invalid (also sometimes known as a
“false positive” reaction)
Next, add one drop of hydrogen peroxide to the swab tip.
o Blood is most likely present/indicated if a bright
blue/purplish color is observed within
several seconds. The possibility also exists that you can
have a false negative result,
meaning that blood was actually present in the sample but
the concentration may be
diluted or compromised, thus not producing a color reaction.
Note: It is suggested that an area adjacent to the sampled
evidence stain be tested using the
same procedure described above. This test should yield a
negative reaction and is called a
negative control.
Tetramethylbenzidine (TMB) presumptive pest kit
instructions:
Use the known bloodstain control card to test the reagents
prior to testing the evidence stains.
Ideally, this control test should yield a POSITIVE reaction
and is called a positive control.
o To conduct the positive control test, you will follow the
directions below, getting the listed
result. Then you would repeat these steps to conduct the
actual presumptive tests on the
samples listed in the chart.
First, use a cotton tip swab to “retrieve” a sample of the
suspected reddish stained sample. If the
sample stain is dry, you can moisten the cotton tip swab
with the distilled water from your kit.
Then, add one drop of TMB reagent to the swab with the
suspected stain. Remember to not add
the reagent to the swab over the evidence; twist to the side
as you squeeze a drop of the reagent
onto the swab tip.
o If a bright blue/greenish color develops after the
addition of the TMB reagent but before
the addition of the hydrogen peroxide, this indicates that a
contaminant is present and the
test should be considered invalid (also sometimes known as a
“false positive” reaction)
Next, add one drop of hydrogen peroxide to the swab tip.
o Blood is most likely present/indicated if a bright
blue/greenish color is observed within
several seconds. If a bright blue/purplish color develops
after the addition of the TMB
reagent but BEFORE the addition of the hydrogen peroxide,
this indicates that a
contaminant is present and the test should be considered
invalid (also sometimes known
as a “false positive” reaction).
o The possibility also exists that you can have a false
negative result, meaning that blood
was actually present in the sample but the concentration may
be diluted or compromised,
thus not producing a color reaction.
Note: It is suggested that an area adjacent to the sampled
evidence stain be tested using the
same procedure described above. This test should yield a
negative reaction and is called a
negative control.
Results Chart
Sample Interpretation Test Used
Red paint Positive False
Positive No Reaction KM LCV TMB
Fresh potato (smashed) Positive False
Positive No Reaction KM LCV TMB
Cooked tomato sauce Positive False
Positive No Reaction KM LCV TMB
Red food coloring Positive False
Positive No Reaction KM LCV TMB
Fresh, raw beet Positive False
Positive No Reaction KM LCV TMB
Blood Sample from Kit Positive False
Positive No Reaction KM LCV TMB
Tests Used KM Phenolphthalein (Kastle-Meyer)
LCV Leuco-Crystal Violet
TMB Tetramethylbenzidine
LCV Phenolphthalein TMB
Module 3 Experiment B
Experiment B: Bloodstain Geometry Experiment
The purpose of this lab is to help you become familiar with
the basic geometric shapes and patterns
formed by droplets of blood when they impact various target
surfaces at a 90° angle. You should also
learn the about the effects that various surface textures
will have on the geometry of the blood droplets as
well as how you articulate your recognition, documentation,
and interpretation of the bloodstain evidence.
Finally, you will observe what blood may look like after
traces of it are removed using a presumptive blood
test.
You will document your findings, sketch the appearance of
the stains, and answer some questions about
the experiment for submission to the instructor.
Caution! You may create additional artificial blood for this
experiment. In doing so, be aware that
the ingredients/materials you use may stain items so make
certain the “equipment” used for this
experiment is disposable.
Artificial Blood Preparation
There are three variations for creating your artificial
blood. Choose the method that works best for you.
1. Use 4 oz of evaporated milk, 2-3 tablespoons of tomato
paste, and red food dye. Mix to the
viscosity of blood and use water to thin as necessary. This
artificial blood mixture should be
freshly made; it is only good for a few days. Store in
refrigerator if necessary.
2. Use 4 oz of Carnation®
dry milk, red food dye, and water. Mix to the viscosity of
blood.
3. Use 4 oz of white corn syrup and red food dye. Mix to the
appearance of blood.
Note: In lieu of making artificial blood, you can attempt to
use one of your synthetic blood samples or use
your spatter blood sample
Equipment and Supplies
Equipment/supplies from your CRM 343 bodily fluids kit:
1. Plastic dropping pipettes
2. A few pairs of gloves
3. A face mask (as a precaution against artificial blood,
since it can be messy)
4. L-Scale labels to measure and document your stains
5. Synthetic/Spatter Blood Sample
6. BlueStar®
Tablets (Presumptive Test for Training)
Supplies from your local craft or discount department store:
1. A 12-inch square piece of cardboard (or something of a
like texture)
2. A 12-inch square piece of plywood (or something of a like
texture)
3. A 12-inch piece of ?inch thick smooth, clear piece of
acrylic (or something of a like texture)
4. Paper towels
5. Tape measure
6. Ruler
a. If you want to experiment on an additional surface, you
can also drop blood onto a floor tile,
carpet, or piece of clothing
Directions:
1. Drop one drop of artificial blood straight downward onto
each surface (cardboard, plywood,
acrylic, piece of paper towel) texture being tested from the
height of 1 inch, 2 inches, 36 inches,
and 72 inches.
2. The test surfaces should be placed flat on the floor (not
a carpeted floor) and the pipette should
be held perpendicular to the surface when the blood drops
are released.
3. Draw a well-mixed quantity of the artificial blood into
the pipette and wipe off any excess blood
from the outside of the pipette with another paper towel. Be
careful not to include any air bubbles
with the blood.
4. Make your observations while the stains are wet and after
the stains have thoroughly dried.
5. Once stains are dry and properly documented, attempt to
clean up the dried blood using a slightly
damp towel.
6. Utilizing the BlueStar® Tablets to make a presumptive
test solution, you will visualize the cleaned
up blood, photographing your results and documenting your observations.
Note: To make the
presumptive test solution, simply place both tablets into
the spray bottle and add four ounces (4
oz.) of water. Shake thoroughly until tablets are completely
dissolved. Dispose of empty
packaging safely.
Report Observations and Documentation
1. Sketch the appearance of your blood drops at each height.
Either photograph or scan your sketch
for submission.
2. For each surface texture being examined, make the
following observations and record your
answers:
a. Describe the texture of the surface: hard/soft;
smooth/rough; porous or nonporous
b. Describe the edge characteristics of the resulting stains
c. Measure the diameter of each drop (in millimeters)
d. Describe the extent of peripheral satellite spatter
e. Discuss what effect changing the dropping height had on
the resulting stains
f. Document your observations of the effect of BlueStar®
on the cleaned up blood; was it what
you expected? Why or why not? Did you have difficulty
applying the solution?
g. If possible, experiment with other surface textures (as
previously described) and document
your results
Submit your sketch and observation report to the Dropbox and
Turnitin.com no later than Sunday 11:59 PM EST/EDT.
Module 5 Experiment C
Experiment C: Virtual Autopsy Discovery and Evaluation
Follow the steps below to complete the virtual autopsy
assignment.
1. First, Read the study, “Virtual Autopsy in Forensic
Medicine,” by Dr. Anders Persson at the
following website:
http://www.healthcare.siemens.com/computed-tomography/ct-customer-information-portal/out-of-theordinary/highlight-science
(You can download the study from this page)
2. View the “virtual autopsy table” demonstration at
http://vimeo.com/6866296
3. Review the “Virtual Autopsy” at http://australianmuseum.net.au/interactive-tools/autopsy
4. Answer the following questions to the best of your
ability:
a. Was the “virtual autopsy” and video of the new “virtual
autopsy table” informative? How so? Did it
enhance the knowledge available from your textbook?
b. Since you may not have had prior knowledge of what an
autopsy encompasses, how did the
virtual autopsy assist you in understanding the process
better?
c. If you could add to this virtual autopsy video, what
would you suggest? If nothing should be
added, in what way was the video adequate?
d. How does “viewing” an autopsy (if it does) change your
perspective of death investigation?
Which of the Saint Leo University Core Values is most
applicable to the process of the autopsy
examination? In what way does the Core Value apply? Why is
this so important?
Submit your answers to the Assignment box no later than
Sunday 11:59 PM EST/EDT. (This Assignment box
maybe linked to Turnitin.)
Module 6 Experiment D
Experiment D: Biological Evidence Collection and Packaging
Experiment
The purpose of this lab is to give you practical experience
in the method of collecting biological evidence
samples and packaging these items in such a way to prevent
contamination. In doing so, you will
understand that any biological item at a scene should be
handled with caution, as the potential for
biohazards exist. Additionally, you will ensure that proper
packaging maintains chain of custody/chain of
evidence, assuring that the item collected at the scene is
the same item analyzed in the lab and
presented in court.
Caution! The following presumptive chemicals can be
dangerous. Please follow all safety
instructions and/or MSDS information which can be found
through online research. These
chemicals should not be swallowed or inhaled. They may also
damage or stain clothing.
After you have completed the exercise, write a two-page
synopsis about the experience. You should also
include images of your folds, seals, and final packaging
(documentation). Did your perception of evidence
packaging differ from the actual practical nature of
collection and packaging evidence? What obstacles
did you encounter in your experience? Was it difficult or
simple?
Submit your synopsis to the Dropbox and Turnitin.com no
later than Sunday 11:59 PM EST/EDT.
Equipment and Supplies
Supplies from your CRM343 bodily fluids kit:
Tweezers (for picking up items)
Hexagon OBTI presumptive test kit
Sero-Stix (presumptive test kit)
Semen presumptive test kit
Gloves
Face mask
Biohazard labels
Supplies from home:
Rubbing alcohol
Sheets of paper for making pharmaceutical/druggist’s folds
o You can also use small manila coin envelopes if you have
them from a previous kit
Small paper bags
Permanent marker (such as a Sharpie®
) for documentation
Camera
Directions:
Using the tweezers and gloves provided in your kit and a
bottle of rubbing alcohol you purchase
from a store, you will be required to collect five items (or
swabs of these items) which may contain
a bodily fluid that can be analyzed in a forensic crime
laboratory.
o Yes, you will have to use your imagination, unless you
want to collect actual samples
from family members or from yourself.
? Caution! If collecting actual bodily
fluids, be certain to dispose of them properly,
using your jurisdiction’s requirements for disposal of
fluids.
o After collecting each item, you will clean your tweezers
with rubbing alcohol. This is done
to decontaminate your equipment so cross-contamination can
be eliminated.
Conduct presumptive tests (as you did in Module 2) on items
you’ve collected which might
contain blood and semen.
o This time, you will use the Hexagon OBTI presumptive blood
test, the Semen
Presumptive Test, and the Sero-Stix presumptive blood test.
Read the instructions at
the end of this document for information on each kit and
follow as directed.
Ideally, using full personal protective equipment (PPE), you
would properly collect all items in
pharmaceutical (druggist’s) folds or an appropriate evidence
container, such as a small paper bag
(for example, the paper bags used in grocery
stores/supermarkets).
o For the purposes of this course/experiment, you will use
your gloves and face mask as
your modes of PPE.
All pharmaceutical/druggist’s folds must contain the
following information (DICED):
o Date and time item collected
o Initials (name) of person collecting item
o Case number assigned to this class experiment
o Exhibit (item) number (for example: is it 1 of 2?)
o Description of location where found/description of item
found; and
o What bodily fluid it might contain/what it would be
processed for
? If the item is too large to place in a
pharmaceutical/druggist’s fold, the above
listed DICED information should be listed on the exterior
packaging (such as a
medium sized yellow manila coin envelope or similar
packaging)
All pharmaceutical/druggist’s folds would be placed into a
“main” evidence bag (such as a larger
paper bag from the grocery store), making certain to seal
and initial all evidence (see example
provided).
You will finally place a biohazard sticker on the outside of
each item’s container if you suspect it is
a biohazardous substance. This sticker should be visible to
anyone who might come in contact
with the evidence. At the crime scene, all biological items
are considered hazardous. Good
packaging will keep items intact and protect without damage.
You will photograph your folds, seals and evidence packaging
for documentation purposes.
The bodily fluids you should attempt to collect and package:
Semen
Saliva
Blood
Urine
Sweat
Items normally collected in crime scene cases for bodily
fluids can include the following:
Clothing
Eating/drinking materials
Sharp instruments which might be used as weapons
Ordinary items that might come in contact with fluids
Any other items from which you might collect a bodily fluid
at a scene
Instructions for Using Hexagon OBTI
Open white foil package containing a testing well platform.
In the small clear container with red cap is a transport
medium (liquid).
Unscrew the red cap. Using the wand, gently touch the tip of
the wand to the presumed human
blood trace.
This sample trace is transferred into the tube with
transport medium when you put the red cap
back on.
With the red cap screwed back on, shake the sample gently
inside the transport medium.
This mixture is now added, drop by drop, to the test in the
sample well (S) at the lower end of the
testing platform.
A positive sample reaction is typically detected within
two-three minutes. Negative results should
be confirmed after 10 minutes.
Results: A single blue line means the testing liquid is
working fine but no human blood has been
detected. Two blue lines mean the test has detected human
blood.
Once testing is complete, document your findings and dispose
of the testing well platform by
placing it back in the foil package. You can dispose of the
transport medium in the same fashion.
Instructions for Using Sero-Stix
A Sero-Stix is a stiff plastic strip which has at one end a
absorptive patch containing a
presumptive test reagent for blood.
o The test is based upon the pseudoperoxidase action of
hemoglobin which catalyzes the
reaction of tetramethylbenzedine and organic peroxide.
You can “swab” the patched end onto a stain that is
suspected of having blood.
o The patched end can also be rubbed on a dry stain, then
adding a drop of water to
moisten.
The patch at the end of the strip will turn a dark blue
color if the suspected stain contains
hemoglobin (or blood derivatives).
o Recall this is a presumptive test. It is not confirming
the presence of blood
Dispose of the used plastic strips in an appropriate
container.
Instructions for Using Semen Presumptive Test Kit
On the front of the plastic baggie containing the kit, you
will carefully read the directions in their
entirety as listed.
Module 7 Research
Paper
Research Paper Guidelines and Grading Rubric
Topic
Each student will complete a written five-page research
paper based on a case in which bodily fluids
(bloodstains, DNA evidence, etc.) were analyzed and led to
prosecution in the court system. For
example, the cases of Marilyn Sheppard and Nicole Brown
Simpson demonstrate how bloodstain pattern analysis assisted in the prosecution
of the criminal trials. In addition, the paper should relate the selected case
to the Saint Leo University core value of Respect.
Research The paper must include two scholarly references
(i.e., peer-reviewed scholarly journal articles) as well as one textbook, of
which the course text is allowed. If you are uncertain as to what a “scholarly
journal source” represents, please contact your instructor or the Cannon
Memorial Library for assistance.
Format
The completed paper should adhere to APA (6th edition)
standards. In addition, please note the following requirements:
Use of 12-point Times
New Roman font, double-spacing, and one-inch margins throughout
Approximately five
pages in length (excluding title page and references)
Use of a header (i.e.,
the shortened title of paper and page number)
Proper citation of
sources in the body of the paper and on a separate “References” page
Submission
The research paper must be submitted to the Dropboxno later
than Sunday 11:59 PM EST/EDT of Module 7.
(The Dropbox is
linked to Turnitin.)
