Presentation on theme: "Chapter 10 Blood “Out damned spot! Out, I say Here’s the smell of the blood still, All the perfumes of Arabia will not Sweeten this little hand. Oh, Oh,"— Presentation transcript:
Chapter 10 Blood “Out damned spot! Out, I say Here’s the smell of the blood still, All the perfumes of Arabia will not Sweeten this little hand. Oh, Oh, Oh!” —William Shakespeare’s Lady Macbeth, in Macbeth
Chapter 10Kendall/Hunt Publishing Company1 Blood That an antibody and an antigen of different types will agglutinate, or clump, when mixed together. That the significance of the evidence depends on a characteristic’s relative occurrence in the population. Students will learn:
Chapter 10Kendall/Hunt Publishing Company2 Blood Students will be able to: Determine whether a stain is blood. Determine whether a bloodstain is human or animal blood. Determine the blood type of a simulated bloodstain using the ABO/Rh system. Explore bloodstain patterns as a function of velocity, direction, and height of fall. Use technology and mathematics to improve investigations and communications.
Chapter 10Kendall/Hunt Publishing Company3 Serology Serology is the examination and analysis of body fluids. A forensic serologist may analyze a variety of body fluids including saliva, semen, urine, and blood. From 1950 to the late 1980’s, forensic serology was a most important part of lab procedures. With the development of DNA techniques, more time, money, and significance was placed in developing DNA labs. However, with limited funds and the time required for DNA testing, most labs still use many of the basic serology testing procedures.
Chapter 10Kendall/Hunt Publishing Company4 What is blood? Type of connective tissue that transport substances between body cells and the external environment
Chapter 10Kendall/Hunt Publishing Company5 Volume Men: 1.5 gallons Women: 0.875 gallons 55% plasma 45% formed elements (cells and platelets)
Chapter 10Kendall/Hunt Publishing Company7 Blood Characteristics Plasma is the fluid portion of the blood (55%) Cells (45%) Erythrocytes are red blood cells. They are responsible for oxygen distribution. Leukocytes are the white blood cells; they are responsible for “cleaning” the system of foreign invaders. Thrombocytes or platelets are responsible for blood clotting Serum is the liquid that separates from the blood when a clot is formed.
Chapter 10Kendall/Hunt Publishing Company8 Human Blood Red blood cells are most numerous 5 to 6 million per mm 3 White blood cells are larger and less numerous 5 to 10,000 per mm 3 Platelets are tiny, cellular fragments 350 to 500,00 per mm 3
Chapter 10Kendall/Hunt Publishing Company9 Erythrocytes Biconcave discs (increased surface area) 1/3 blood cell is hemoglobin Gives blood its color Lifespan is 120 days
Chapter 10Kendall/Hunt Publishing Company10 Leukocytes Protect against disease WBCC: 5,000-10,000 Rising number may indicate infection Below 5,000 indicates typhoid fever, influenza, measles, mumps, chickenpox, AIDS, or poliomyelitis
Chapter 10Kendall/Hunt Publishing Company11 Clinical Application Anemia: too few rbcs or too little hemoglobin Sickle cell anemia: abnormal hemoglobin formed becomes becomes spiky and sharp during stressful situations; ruptures and dams up small blood vessels
Chapter 10Kendall/Hunt Publishing Company12 Unknown Stain at a Scene Questions to be answered: Is it blood? Is it human blood? Whose is it? Determine blood type, alcohol content, drugs present Determine the method(s) in which blood may have been deposited
Chapter 10Kendall/Hunt Publishing Company13 Presumptive Tests for Blood Determination Kastle-Meyer color test a mixture of phenolphthalein and hydrogen peroxide Hemoglobin breaks down hydrogen peroxide with the production of oxygen Oxygen reacts with phenolphthalein reagent to produce a deep pink color cause the formation of a deep pink color if blood is present
Chapter 10Kendall/Hunt Publishing Company14 Presumptive Tests for Blood Determination Hematest® tablet or Hemastix test strip Hemoglobin breaks down hydrogen peroxide with the production of oxygen Oxygen reacts with the benzidine product in the tablet or strip causing a blue-green color Luminol test reaction with blood to produce light making old stains glow (chemiluminesce) and works on dried or washed blood stains
Chapter 10Kendall/Hunt Publishing Company15 Human vs Animal Blood Microscopic observation Precipitin test - uses animal serum that contains antibodies specific to human antigens Blood is injected into a rabbit antibodies are formed The rabbit’s blood is extracted as an antiserum The antiserum is placed on sample blood The sample will react with human proteins if human blood is present. This test is very sensitive and requires only a small amount of blood.
Chapter 10Kendall/Hunt Publishing Company17 Historical Perspective of Blood Typing Around 1900, Karl Landsteiner discovered that there are 4 different types of human blood based on the presence or absence of specific antigens found on the surface of the red blood cells. In 1940, Landsteiner and Weiner reported the discovery of the Rh factor by studying the blood of the Rhesus monkey. 85% of Caucasians, 94% of Black Americans and 99% of all Asians are Rh positive.
Chapter 10Kendall/Hunt Publishing Company18 ABO Blood Group Based on presence or absence of two major protein antigens on red blood cell membranes--- antigen A and antigen B A, B, AB, O Have or lack antigen and have or lack antibody Mismatched blood transfusion causes agglutination
Chapter 10Kendall/Hunt Publishing Company19 Blood Terminology ABO blood groups—based on having an A, B, both or no antigens on red blood cells Rh factor—may be present on red blood cells; positive if present and negative if not Antigen—a substance that can stimulate the body to make antibodies. Certain antigens (proteins) found in the plasma of the red blood cell’s membrane account for blood type. Antibody—a substance that reacts with an antigen Agglutination—clumping of red blood cells; will result if blood types with different antigens are mixed
Chapter 10Kendall/Hunt Publishing Company20 Blood Typing Blood type A has antigen A on the surface of the cell and will agglutinate with blood type B. Blood type B has antigen B on the surface of the cell and will agglutinate with blood type A. Blood type AB has antigens A and B on the surface of the cells and will not agglutinate with either type A or B blood. Blood type O has neither antigen A or B and will not agglutinate.
Chapter 10Kendall/Hunt Publishing Company21 Blood Groups Type Antigen Antibody Can Give Blood To Can Get Blood From A B AB O A B A and B Neither A nor B B A Neither A nor B A and B A, ABO, A B, ABO, B AB A, B, O, AB O
Chapter 10Kendall/Hunt Publishing Company22 Population Distribution of Blood Types in the U.S. TypePercent O A B AB 45 40 11 4
Chapter 10Kendall/Hunt Publishing Company23 Rh Blood Group Named after the rhesus monkey If Rh antigen is present, then positive Anti-Rh only appear in Rh-negative persons in response to special stimulation Fetus can develop erythroblastosis fetalis
Chapter 10Kendall/Hunt Publishing Company24 Blood Pattern Reconstruction Scene Pattern Reconstruction 1. Stain condition 2. Pattern 3. Distribution 4. Location 5. Directionality Lab Results Reconstruction 1. Genetic marker typing 2. Age Determination 3. Source Determination 4. Race Determination 5. Sex Determination —From “Cracking Cases” by Dr. Henry C. Lee
Chapter 10Kendall/Hunt Publishing Company25 Blood Spatter Evidence A field of forensic investigation which deals with the physical properties of blood and and the patterns produced under different conditions as a result of various forces being applied to the blood. Blood, as a fluid, follows the laws of physics.
Chapter 10Kendall/Hunt Publishing Company26 People of Historical Significance Paul Kirk (1902-1970) was a professor of criminalistics and biochemistry at Berkeley in California. He actively assisted law enforcement organizations from 1935 to 1967. His book, Crime Investigations, contained a chapter in which he discussed the application of blood stain pattern analysis to criminal investigations. Dr. Kirk analyzed the blood stain pattern photos from the Sam Sheppard case and was instrumental in Sheppard’s release at his second trial. Find out more about the case at Courttv’s crime library.
Chapter 10Kendall/Hunt Publishing Company27 Sam Sheppard Case Sam heard wife call for him upstairs Went to her and found her covered in blood Heard noise downstairs and saw someone moving towards lake Struggled with the man Sam was choked to unconsciousness Sam served 10 years before Dr. Kirk concluded that killer was left-handed and Sam was right- handed
Chapter 10Kendall/Hunt Publishing Company28 Blood Droplet Characteristics A blood droplet will remain spherical in space until it collides with a surface Once a blood droplet impacts a surface, a bloodstain is formed. A droplet falling from the same height, hitting the same surface at the same angle, will produce a stain with the same basic shape. How will the shape change as the height is increased or decreased?
Chapter 10Kendall/Hunt Publishing Company29 Categories of Bloodstains Passive Transfer Projected
Chapter 10Kendall/Hunt Publishing Company30 Passive Drops created or formed by the force of gravity acting alone Includes: Clots Drops Drip patterns Pools
Chapter 10Kendall/Hunt Publishing Company31 Transfer A transfer bloodstain is created when a wet, bloody surface comes in contact with a secondary surface. Includes: Contact bleeding Swipe or Smear Wipe Smudge
Chapter 10Kendall/Hunt Publishing Company32 Projected when an exposed blood source is subjected to an action or force, greater than the force of gravity size, shape, and number of resulting stains will depend on the amount of force utilized to strike the blood source Includes: Arterial Spurt Gush
Chapter 10Kendall/Hunt Publishing Company33 Conditions Affecting Shape of Blood Droplet Size of the droplet Angle of impact Velocity at which the blood droplet left its origin Height Texture of the target surface On clean glass or plastic—droplet will have smooth outside edges On a rough surface—will produce scalloping on the edges
Chapter 10Kendall/Hunt Publishing Company34 Questions Answered by Blood Spatter Interpretation The distance between the target surface and the origin of blood The point(s) of origin of the blood Movement and direction of a person or an object The number of blows, shots, etc. causing the bloodshed and/or the dispersal of blood. Type and direction of impact that produced the bloodshed The position of the victim and/or object during bloodshed Movement of the victim and/or object after bloodshed
Chapter 10Kendall/Hunt Publishing Company35 Bloodstain Terminology Angle of impact—angle at which blood strikes a target surface. Bloodstain transfer—when a bloody object comes into contact with a surface and leaves a patterned blood image on the surface Backspatter—blood that is directed back toward the source of energy Cast-off—blood that is thrown from an object in motion
Chapter 10Kendall/Hunt Publishing Company36 Bloodstain Terminology Contact stain—bloodstains caused by contact between a wet blood-bearing surface and a second surface which may or may not have blood on it Transfer—an image is recognizable and may be identifiable with a particular object Swipe—wet blood is transferred to a surface which did not have blood on it Wipe—a non-blood bearing object moves through a wet bloodstain, altering the appearance of the original stain
Chapter 10Kendall/Hunt Publishing Company37 Bloodstain Terminology Directionality—relates to the direction a drop of blood traveled in space from its point of origin Terminal velocity—the greatest speed to which a free falling drop of blood can accelerate in air. It is dependent upon the acceleration of gravity and the friction of the air against the blood—approximately 25.1 feet/second. High velocity—greater than 25 feet per second, usually 100 feet per second; gives a fine mist appearance Medium velocity—5 to 25 feet per second Low velocity—5 feet per second or less
Chapter 10Kendall/Hunt Publishing Company38 Directionality When a droplet of blood strikes a surface perpendicular (90 degrees) the resulting bloodstain will be circular. Blood that strikes a surface at an angle less than 90 degrees will be elongated or have a tear drop shape.
Chapter 10Kendall/Hunt Publishing Company39 Bloodstain Patterns The shape of a blood drop: Round—if it falls straight down at a 90 degree angle. Elliptical—blood droplets elongate as the angle decreases from 90 to 0 degrees; the angle can be determined by the following formula:
Chapter 10Kendall/Hunt Publishing Company40 Impact The more acute the angle of impact, the more elongated the stain. 90 degree angles are perfectly round drops with 80 degree angles taking on a more elliptical shape. At about 30 degrees the stain will begin to produce a tail. The more acute the angle, the easier it is to determine the direction of travel.
Chapter 10Kendall/Hunt Publishing Company41 Bloodstain Patterns The harder and less porous the surface, the less the blood drop will break apart. The softer and more porous the surface, the more a blood drop will break apart. The pointed end of the blood stain faces the direction of travel.
Chapter 10Kendall/Hunt Publishing Company42 Area of Intersection and Convergence The location of the blood source can be determined by drawing lines from the various blood droplets to the point where they intersect. The area of convergence is the point of origin; the spot where the “blow” occurred. It may be established at the scene with measurement of angles by use of strings.
Chapter 10Kendall/Hunt Publishing Company43 Point and Area of Convergence The point of convergence is the intersection of two bloodstain paths, where the stains come from opposite sides of the impact pattern. The area of convergence is the box formed by the intersection of several stains from opposite sides of the impact pattern.
Chapter 10Kendall/Hunt Publishing Company44 Blood Evidence Class evidence for blood would include blood type. If you can determine the DNA you would have individual evidence. Blood stain patterns are considered circumstantial evidence in a court room. Experts could argue many points including direction of travel, height of the perpetrator, position of the victim, left/right hand, whether the body was moved, etc.
Chapter 10Kendall/Hunt Publishing Company45 Secretors 80% of the population are secretors. Their blood-type antigens are found in high concentration in their body fluids such as saliva, semen, vaginal secretions and gastric juice.
Chapter 10Kendall/Hunt Publishing Company46 People in the News Herbert L. MacDonell is considered by many as the father of modern bloodstain pattern analysis. He is the director of the Lab of Forensic Science and founder of the Bloodstain Evidence Institute (1973) in Corning, NY. His work, Bloodstain Pattern Interpretation, helped to jump start this discipline. He has consulted on criminal cases in all 50 states, in addition to testifying in the O.J. Simpson trial and in the assassination cases of Sen. Robert F. Kennedy and Dr. Martin Luther King Jr.
Chapter 10Kendall/Hunt Publishing Company47 More about Serology For additional information about blood evidence, and famous crimes that involves serology, check out Court TV’s Crime Library at: www.crimelibrary.com/criminal_mind/forensics/serology/1.html
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