Forensic Science Unit 6

1 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.

2 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 _____.

3 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.

4 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.

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.

6 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.

7 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 = 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). +a+protractor&rlz=1C1 CHBF_enUS895US896&oq=making+a+protractor &aqs= #kpvalbx=_K227 XryMFdLL1 QGrp5iQCg38 17 18 19 Instructions: Read the following Case Study and complete the worksheet that follows 20 21 22 Blood Detection Instructions: Take NOTES.

8 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.

9 Chemical: Acid/base indicator, laxative. Human blood pH (acid or base?) In- pH (_____) * it turns colorless in acidic solutions and pink in basic solutions. This link shows a Phenolphthalein Test: 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 This link shows a Leucomalachite green Test: Benzidine Used in making Dyes and _____ blood stains Benzidine has been linked to _____ and _____ cancer Below is a link to further describe Benzidine: This link shows a Benzidine Test: All of these are presumptive test, meaning the analysis of a sample to establish one of the following: 1.

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