1. Forensic Science

2. What makes up our blood? RED BLOOD CELLS (Erythrocytes) – The most abundant cells in our blood; they are produced in the bone marrow and contain a protein called hemoglobin that carries oxygen to our cells. WHITE BLOOD CELLS (Leukocytes) – They are part of the immune system and destroy infectious agents called pathogens. PLASMA – This is the yellowish liquid portion of blood that contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection. PLATELETS (Thrombocytes) – The clotting factors that are carried in the plasma; they clot together in a process called coagulation to seal a wound and prevent a loss of blood.

5. Blood Facts The average adult has about FIVE liters of blood inside of their body, which makes up 7-8% of their body weight. Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy. There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell.

6. Blood Facts Blood has certain properties that can be compared to water. Surface tension enables blood droplets to maintain a sphere shape. WaterBlood Viscosity1.0 mP·s -1 3-4 mP·s -1 Surface tension 0.073 N·m -1 0.058 N·m -1 Density1000 kg/m 3 1060 kg/m 3

7. Blood Facts

8. Genetics of Blood Types Your blood type is established before you are BORN, by specific GENES inherited from your parents. You inherit one gene from your MOTHER and one from your FATHER. These genes determine your blood type by causing proteins called AGGLUTINOGENS to exist on the surface of all of your red blood cells.

9. What are blood types? There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations. Blood Types AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB

10. Blood Typing Less expensive and quicker then DNA profiling Considered to be class evidence Discovered by Karl Landsteiner –The presence or absence of particular proteins found embedded within the cell of plasma membranes determines a persons blood type. –Antibody reaction test is used to identify each blood type

11. Blood Typing Tests Blood typing is a way to identify and match blood samples Three separate tests are performed –The patients blood is mixed with antibodies that bind to A protein –If it clumps then the patient has A blood –The test is repeated with B and tested for Rh factor

12. How common is your blood type? 46.1% 38.8% 11.1% 3.9%

13. Probability To determine the probability of two separate events, it is necessary to multiply their individual probabilities Example One: –What is the chance of throwing dice and getting two sixes? The probability of one die showing a six is 1/6 (one side out of six) The probability of the other die showing a six is 1/6 So the chance of throwing two dice and getting both showing a six is calculated by multiplying the individual probabilities: 1/6 X 1/6 = 1/36

14. Probability Example 2: What percentage of the population would have A+ blood? –Type A blood = 42% of population –Rh = 85% of the population Step 1 convert the percentages to decimals –Type A blood= 42% =.42 of the population –Rh factor = 85% =.85 of the population Multiply the decimals –.42 X.85 =.357 of the population should have both A and Rh+ Multiply by 100 to convert the decimal to a percentage –.357 X 100% = 35.7% of the population should be both A and Rh+

15. Probability Example 3: What percentage of the population would have the following combination of blood-type proteins? Type O-, Mn Step 1 Convert % to decimals –Type O = 43% =.43 –Rh- = 15% =.15 –MN = 48% =.48 Step 2 Multiply the decimals –.43 X.15 X.48 =.031 Step 3 Multiply by 100 to convert decimal to a % –.031 X 100% = 3.1% So about 3 out of 100 people will be O- with MN

16. Antibodies White blood cells (B-Lymphocytes) Secrete antibodies Y-shaped Bind to an antigen Bind at the tip of the antibodies The antibody recognizes the foreign substance as an invader and attaches to it

18. Antibody/Antigen Response Test The immune system launches the Antigen- Antibody response against invaders. This includes red blood cells When the wrong blood type is introduced to the body two things happen –1. B lymphocytes make specific antibodies against that protein –2. Phagocytes engulf the invader

19. Blood Transfusions A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. Who can give you blood? People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. Rh +  Can receive + or - Rh -  Can only receive - Universal Donor Universal Recipient

20. Agglutination When the antibody attaches itself to a red blood cell agglutination occurs (clumping) This can occur during a blood transfusion causing the flow of blood to stop Without blood flow cells can not receive oxygen and remove carbon dioxide

21. Rh Factors Scientists sometimes study Rhesus monkeys to learn more about the human anatomy because there are certain similarities between the two species. While studying Rhesus monkeys, a certain blood protein was discovered. This protein is also present in the blood of some people. Other people, however, do not have the protein. The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor. If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not contain the protein, your blood is said to be Rh negative (Rh-). A+ A- B+ B- AB+ AB- O+ O- http://www.fi.edu/biosci/blood/rh.html

22. Blood Evidence Blood samples – Can be analyzed to determine blood type and DNA, which can be matched to possible suspects. Blood droplets – Can be analyzed to give clues to the location of a crime, movement of a victim, and type of weapon. Blood spatter – Can be analyzed to determine patterns that give investigators clues to how a crime might have happened.

23. Microscopic Views Bird Blood Cat Blood Dog Blood Fish Blood Frog Blood Snake Blood Human Blood Horse Blood

24. What does the abbreviation BPA represent? Bloodstain Pattern Analysis What can an investigator learn from the analysis of a blood spatter?  Type and velocity of weapon  Number of blows  Handedness of assailant (right or left-handed)  Position and movements of the victim and assailant during and after the attack  Which wounds were inflicted first  Type of injuries  How long ago the crime was committed  Whether death was immediate or delayed How does a blood droplet form? Click the image for an animation.

25. Light Source Investigators will first examine the crime scene to look for areas that may contain blood. They may use a high-intensity light or UV lights to help them find traces of blood as well as other bodily fluids that are not visible under normal lighting conditions. How is blood evidence detected at a crime scene? Blood Reagent Tests These tests, referred to as presumptive tests, are used to detect blood at crime scenes based upon the properties of hemoglobin in the blood. Further tests at the crime lab can determine if it is human blood or not. Examples: Phenolphthalein is a chemical that is still utilized today and is usually referred to as the Kastle-Meyer test and produces a pink color when it reacts with hemoglobin. HemaStix is a strip that has been coated with tetramethylbenzidine (TMB) and will produce a green or blue- green color with the presence of hemoglobin. Kastle-Meyer Test Video HemaStix

26. Luminol This chemical is used by crime scene investigators to locate traces of blood, even if it has been cleaned or removed. Investigators spray a luminol solution is throughout the area under investigation and look for reactions with the iron present in blood, which causes a blue luminescence. One problem is that other substances also react, such as some metals, paints, cleaning products, and plant materials. Another problem is that the chemical reaction can destroy other evidence in the crime scene. Luminol Reaction LCV or Leuco Crystal Violet, is one type of chemical process that is used for blood enhancement. Using this test helps to make the blood evidence more visible so it can be photographed and analyzed. Fluorescein This chemical is also capable of detecting latent or old blood, similar to luminol. It is ideal for fine stains or smears found throughout a crime scene. After the solution has been sprayed onto the substance or area suspected to contain blood, a UV light and goggles are used to detect any illuminated areas, which appear greenish-white if blood is present. It may also react to many of the same things as luminol (copper and bleach). Fluorescein Reaction in UV Light

27. Bloodstain Pattern Analysis Terms Spatter – Bloodstains created from the application of force to the area where the blood originated. Origin/Source – The place from where the blood spatter came from or originated. Angle of Impact – The angle at which a blood droplet strikes a surface. Parent Drop Spines Satellite Spatters Parent Drop – The droplet from which a satellite spatter originates. Satellite Spatters – Small drops of blood that break of from the parent spatter when the blood droplet hits a surface. Spines – The pointed edges of a stain that radiate out from the spatter; can help determine the direction from which the blood traveled.

28. Passive Bloodstains –Patterns created from the force of gravity –Drop, series of drops, flow patterns, blood pools, etc. Projected Bloodstains –Patterns that occur when a force is applied to the source of the blood –Includes low, medium, or high impact spatters, cast- off, arterial spurting, expiratory blood blown out of the nose, mouth, or wound. Transfer or Contact Bloodstains –These patterns are created when a wet, bloody object comes in contact with a target surface; may be used to identify an object or body part. –A wipe pattern is created from an object moving through a bloodstain, while a swipe pattern is created from an object leaving a bloodstain. Images from http://www.bloodspatter.com/BPATutorial.htm Blood Spatter Movie Types of Bloodstain Patterns

29. Blood Spatter Spattered Blood = random distribution of bloodstains that vary in size –Amount of blood and amount of force affect the size of blood spatter. –Can result from gunshot, stabbing, beating Spattered Blood can: Help determine the location of the origin of the blood source. Help determine the mechanism which created the pattern.

30. Stages of impact Stage 1: contact & collapse Stage 2: displacement Stage 3: dispersion Stage 4: retraction

31. Blood Spatter Low impact - blood under the influence of gravity - it just falls. Medium impact -occurs when a force such as a bat is applied. High impact – fine mist of droplets

35. Blood Spatter Faster drop = larger diameter (size) Higher distance = larger diameter Due to air resistance, speed maxes out at distances above about 7 feet However, size of drop also depends on the volume of the drop. Volume depends on object blood originated from (needle = small; bat = large)

36. Blood Spatter Effect of Surface Smooth surface = smooth sphere Rough/porous surface may cause some splatter

37. Blood Spatter Determining Direction of Blood Narrow end of a blood drop will point in the direction of travel.

38. Blood Spatter Determining Direction of Blood If more than one drop (from spatter) results, the point of origin can be determined

39. Blood Spatter Determining Direction of Blood If more than one drop (from spatter) results, the point of origin can be determined

40. Blood Spatter Determining Direction of Blood This is a 2-dimensional point of origin. It is possible to determine the 3-D point of origin

41. Blood Spatter Determining Direction of Blood The angle can be determined mathematically. Width/Length, then take the inverse sin (sin -1 ). This number is the impact angle (90 = perpendicular to surface; <10 at a sharp angle)

42. Blood Spatter Determining Direction of Blood  For each blood drop, a string can be guided back to the point of origin.

43. Blood Spatter In general, for higher impacts, the pattern is more spread out and the individual stains are smaller.  Low impact = beating  High impact = gunshot Types of Spatter

44. Blood Spatter Types of Spatter Gunshot Spatter = can result in a mist-like spatter that indicates a gunshot. –Not all gunshots will result in misting. –If misting is present, it is most likely a gunshot. –Gunshots result in back spatter (where bullet enters) and forward spatter ( where bullet exits).

45. Blood Spatter Types of Spatter Beating and Stabbing Spatter = larger individual stains –First blow usually doesn’t result in spatter since there is not yet any exposed blood.

46. Blood Spatter Types of Spatter Satellite Spatter = Free falling drops of blood that fall onto a spatter pattern. –These drips are usually much larger than impact spatter. –However, blood dripping into blood can create a spatter.

47. Blood Spatter Types of Spatter Castoff Pattern = Blood flung off of swinging object. –Can reconstruct where assailant and victim were positioned.

48. Blood Spatter Types of Spatter Expirated Bloodstain Pattern = Blood can accumulate in lungs, sinuses, and airway. Forcibly exhaled. –Can appear like beating or gunshot pattern –May be mixed with saliva or nasal secretions.