Forensic Science Unit 6

Blood Spatter

Packet #4 May 18th-June 5th Ms. Wines

1

Assignments:

1. Forensic Files: The Wilson Murder, Analysis Worksheet

2. Blood Spatter Notes: Continued

3. Crime Case Studies

a. Case Study #1

b. Case Study #2

4. Bloodstain Practice

5. Lab #8 Distance Falling v. Surface Texture (Optional)

6. Lab #9 Direction of Travel and Angle of Impact

7. Three ‘Messy’ Blood Spatter Experiment (Optional)

8. Case Study: Unconvincing Circumstantial Evidence; Worksheet

9. Blood Detection Notes

10. It’s No Use Trying to Hide Blood … Worksheet

11. Forensic Files: Naked Justice; Questions

12. Case Study: Which Neighbor is a Killer? Worksheet

13. Case Study: The Death of Tammy’s Parrot Questions

14. Bloodstain Pattern Analysis Lab Quiz

2

FORENSIC FILES: The Wilson Murder

Instructions: Watch Forensic Files The Wilson Murder, and complete the Forensic Files analysis

worksheet. https://www.youtube.com/watch?v=VXHFSHqwLmQ

3

Blood Spatter Notes-Continued

Instructions: Take NOTES. Notes are available on google classroom under Unit 6-Blood Spatter 2

Spatter Pattern and type of Wound

• _______ Velocity Impact (______ ft/sec) –

_________-mist spatter pattern

• Size of Droplets – less than 1 mm

– Ex. _________________________

• ___________-Velocity Impact (_____ ft/sec)

– Size – 1-4 mm

– Ex. – ________________, _________________

• ___________-Velocity Impact (______ ft/sec)

– Size – 4 to 6 mm

– Ex – blunt object impact (_______________,

_____________, etc)

Point of origin Angle of Impact

Examination of Directionality of Blood

• Shape provides clues to ______________________ from which blood

____________________

– _________________ drop (width _____ length) – fell straight

down

• Typical of dripping ____________ (passive)

– ______________ drop (width _____ length) – possible to determine direction blood was

_____________

4

• When blood comes into contact with another surface, it adheres or

__________ to it

– Point of impact may appear ___________ and _____________

than rest of drop of blood spatter

• ___________________ – keeps blood moving in direction it was traveling

– As droplet moves ________ from source, it _______________ and may produce a

thinner, ______________-like appearance

• ________ points in direction of blood’s movement

• ____________________ or _____________________ drops may appear in

_____________ of moving droplet of blood

ANGLE of IMPACT - the _____________ angle formed between the ________________ of the blood

drop and the plane of the surface it ______________.

This is the TAIL

________________________

get _________ angle of droplet from W and L

5

Angle of Impact (AOI) Calculations

• accurately measuring the ________ and __________ of a bloodstain, the impact angle can be

calculated using the SIN ____________ below:

AOI = SIN-1 W / L

• W – Width of blood drop

• L – Length of blood drop

6

Lines of Convergence

• ____________ of source can be determined if there

are at least ___________ drops of blood spatter.

• ______________________________ – found by

drawing straight lines down the long axis of blood

spatter and noting where they ______________

• __________ view of the location of the source

Point of Origin

• lies at a point in space _______________ the point of convergence.

o Measurement of the impact angle allows for translation of the 2-D image

(__________________) into a 3-D one (_______________).

7

1. First measure the ______________ from ________ blood stain along its central axis to the

POC (distance = y)

2. Then take the TAN of the ______________ AOI.

3. Third, __________________ the TAN of the AOI by the _________________.

4. Measure that ____________ from the floor up the ________________________ axis and you

will arrive at the Point of Origin (PO)

FORMULA: PO = TAN (AOI) x y

1. Falling directly to floor @ ________________ angle will produce circular drops, with secondary

satellites being more produced in the surface hit is textured. – known as a ______________ fall.

8

2. _________________ spurts or gushes typically found on walls or _____________ are caused by

the pumping actions of the __________.

3. Splashes are shaped like exclamation points. The shape and position of

the spatter pattern can help locate the position of the victim at the time

of attack.

4. Smears are left by the bleeding victim depositing blood as he or she touches or

brushes against furniture or walls.

5. Trails of blood can be left by a bleeding victim as he or she

moves from one location to another. The droplets could be

round or smeared or even appear as spurts.

6. Pools of blood form around a victim who is bleeding heavily and remains in one

place.

9

10

11

Bloodstain Practice Instructions: Complete the worksheet

1. Calculate the angler of impact for the bloodstains below:

12

Below is lab #8 it is not required for you to do, however you may find it enjoyable and this a hands on

activity may give you a better understanding of Blood Spatter Analysis. Encourage a family member to

help you. Additionally, be innovative on how to complete the lab and creating your own “blood like

substance.

Below are other recipes to create fake blood; especially since the instructions ask for paint and you may

not have paint. This recipe calls for materials you may have in your kitchen.

FAKE BLOOD YIELD: Makes about 1 cup

INGREDIENTS

• 3/4 cup corn syrup • 1/4 cup water • 1/2 teaspoon red food coloring • 5 drops blue food coloring • 2 drops green food coloring • 1 tablespoon corn starch

PREPARATION

In a small bowl, whisk together the corn syrup and water. Add the red, blue, and green food colorings and whisk until well combined. Whisk in the corn starch and let the liquid sit for 10 minutes to thicken.

Realistic Fake Blood

The Spruce Crafts / Rain Blanken

For a realistic look, the blood needs to have more color than pure red. A corn syrup base gives this recipe a good thickness, but it is also sticky.

Mix Together

• 2 tbsp Corn syrup • 4 drops of red food coloring • 1 tsp cocoa mix

COMPLETE LAB #9

13

14

15

16

The lab below is not required for you to do, however you may find it enjoyable and this a hands on

activity may give you a better understanding of Blood Spatter Analysis. Encourage a family member to

help you. Additionally, be innovative on how to complete the lab and creating your own “blood like

substance. There are additional recipes to make fake blood listed on page 11 of this packet.

THIS LAB IS MESSY SO COMPLETE IN AN AREA THAT HAS EASY CLEAN UP,AND USE PAPER TO COVER FOR

PROTECTION. ADDITIONALLY, WEAR ATTIRE THAT IS DARK IN COLOR OR YOU DO NOT MIND STAINING.

The conversion for meters to feet is 1 meter = 3.28084 feet. If you do not have a protractor you can use

the link provide below to make a paper protractor (for angles do your best and estimate). https://www.google.com/search?q=making+a+protractor&rlz=1C1CHBF_enUS895US896&oq=making+a+protractor&aqs=chrome..69i57j0l7.79

78j0j7&sourceid=chrome&ie=UTF-8#kpvalbx=_K227XryMFdLL1QGrp5iQCg38

17

18

19

Instructions: Read the following Case Study and complete the worksheet that follows

20

21

22

Blood Detection

Instructions: Take NOTES. Notes are available on google classroom under Unit 6-

Luminol

o Used to find ___________ blood & ___________ stains.

o _____________ in the dark on contact with blood.

o The Luminol test for blood was developed by ______________________ of Germany in ______.

o Luminol is sensitive in the parts per ________________ range even for blood __________ old.

Thus, If you have ____ drop of blood in 999,999 drops of _______, Luminol will glow!!

Drawbacks

o Luminol ______ up blood during its reaction and thus ______________ ________________!

o Other popular crime scene materials like ____________ and ___________ react – Further blood

testing is a __________!

The glow of _________ fades quickly, but the glow of ___________ lasts longer.

____________ can tell if they have blood or something else.

Phenolphthalein

• Phenolphthalein is an ___________________ compound with the formula _________________

• Physical: White Powder, _______________ in water, __________________ in alcohol.

• Chemical: Acid/base indicator, laxative.

• Human blood pH 7.35 (acid or base?)

• In-

pH 8.2-12 (__________)

* it turns colorless in acidic solutions and pink in basic

solutions.

This link shows a Phenolphthalein Test:

https://www.youtube.com/watch?v=ZvhN9DDm9iI

Hydrogen peroxide

• What do you use Hydrogen peroxide on/for?

23

• Why the bubbles?

______________________________________________________________________________

______________________________________________________________________________

Leucomalachite green

Malachite green is an organic compound that is used as a dyestuff and controversially as an

____________________________ in aquaculture. Malachite green is traditionally used as a ______ for

materials such as silk, leather, and paper.

Below is a link to further describe Leucomalachite green

https://www.youtube.com/watch?v=9_fsHnkn02U

This link shows a Leucomalachite green Test:

https://www.youtube.com/watch?v=HMvmEED5YTM

Benzidine

• Used in making Dyes and ____________________ blood stains

• Benzidine has been linked to _______________ and ____________________ cancer

Below is a link to further describe Benzidine:

https://www.youtube.com/watch?v=z9osQAM9rjk

This link shows a Benzidine Test:

https://www.youtube.com/watch?v=nWbPhP4OYiM

All of these are presumptive test, meaning the analysis of “a sample to establish one of the following:

1. The sample is definitely not a certain substance.

2. The sample probably is the substance.

For example, the Kastle–Meyer test ‘(Phenolphthalein Test)’ will show either that a sample is not blood or that the sample is probably blood but may be a less common substance. Further chemical tests are needed to prove that the substance is blood.

Confirmatory tests are the tests required to confirm the analysis. Confirmatory tests cost more than simpler presumptive tests so presumptive tests are often done to see if confirmatory tests are necessary.” https://en.wikipedia.org/wiki/Presumptive_and_confirmatory_tests

24

Instructions: Read and complete the Worksheet-It’s No Use Trying to Hide Blood (pages 23 and 24)

25

26

FORENSIC FILES: Naked Justice

Instructions: Watch Forensic Files Naked Justice and answer the following questions.

https://www.youtube.com/watch?v=kDUdOAzK06U

1. What did investigators use to determine how far away the gun was when it was fired?

2. Where is the gun usually found when people shoot themselves?

3. True or false: The blood in Leann’s palm is consistent with a self inflicted gunshot.

4. True or false: People who have just fired a gun should have gunshot residue on their hands.

5. True or false: Phenolphthalein is a type of chemical test to identify blood.

6. What was found on Mick’s shirt cuff?

7. True or false: High velocity blood spatter can be created when a gunshot wound hits an area with blood and the fine mist of blood blows back toward the gun

8. What did investigators use to find where Leann was when she was shot?

9. Why couldn’t the wound be self-inflicted?

27

Instructions: Read the following Case Study and complete the worksheet that follows

28

29

30

31

Instructions: Read the following Case Study and answer the related questions.

32

33