2 Spatter vs splatter Splatter: random, unorganized Spatter: Not random, affect by gravity, predictableBlood stain Pattern: The pattern of a stain and the quantity of blood present can be important clues to the nature of the accident or crime.BSP Interpretation:what does the blod tell you?
4 Dr Sam and Marilyn Sheppard 35 blows,28 to the headUnknown instrument12> inchesNone of these blows were fatal2 broken teethTorn fingernail.Blood found on most of the walls along with covering a dresser.Dr. Sam Sheppard:Bruiseschipped teethfractured vertebra in his neck.Found shirtless
8 QuestionsWhat Biological evidence will blood provide,, in the bedroom?What information does the Blood stain evidence provide?
9 Dr Sam Sheppard July 4 1954, Reading: HW link: main site:Police report:
10 Do Now: What Biological evidence will blood provide,, in the bedroom? DNABlood type(s)Tool marks/ voidsToxicological ReportsDiseasesSpatter marks (Blood trails, movements)
11 What can Spatter (Bloodstain Evidence) Evidence reveal: .
12 What can Spatter (Bloodstain Evidence) Evidence reveal: Origin(s) of bloodstainPosition of victim & assailantMovement of victim & assailantNumber of blows/shotsDistance of bloodstain from targetDirection from which blood impactedSpeed with which blood left its source
14 Serology The study of antigen-antibody reactions. Tells us human vs. nonhumansSerologists QuestionsIs the sample blood?Is the sample animal blood?If animal blood, from what species?If human blood, what type?Can the sex, age, and race of the source of blood be determined?
15 History of Blood!!!With early Transfusions =instant death due to Coagulation, Karl Landsteiner introduced the A-B-O system,Alexander Weiner, Rhesus monkey, Rh Factor was and over 100 factors actually must be considered when performing a transfusion.Most people are only familiar with the Rh factor, which is technically the D antigen.There are more than 256 antigens, and 23 blood group systems based on association with these antigens.Us Populations: O 43%, A 42%, B 12 %, AB 3%
17 Structure of Blood: Plasma, mostly water Cells Erythrocytes: (RBC) Leukocytes: (WBC)Platelets
18 Major components of Blood, Plasma: Straw colored liquid consisting mainly (90%) of water and (7%) dissolved proteins.Can be found outside of the circulatory system.Also transports:Proteins: (albumin, globulins, fibrinogen)Salts, GlucoseAmino acidsFatty acids,Vitamins, Hormones,Cellular wastes
19 DNA in BLOODDNA can be extracted from blood (if white blood cells which always contain a nucleus are present), and also from sperm, bone marrow, tooth pulp, and hair roots.
20 Blood, however, is commonly used in DNA testing, as per the following steps: Blood samples are collected from the victim, defendant, and crime sceneWhite blood cells are separated from red blood cellsDNA is extracted from the nuclei of white blood cellsA restrictive enzyme is used to cut fragments of the DNA strandDNA fragments are put into a bed of gel with electrodes at either endElectric current sorts DNA fragments by lengthAn absorbent blotter soaks up the imprint; it is radioactively treated, and an X-ray photograph (called an autoradiograph) is produced
21 Liquid Blood Physical properties Behaves as a projectile in motion 2 viscositysurface tensionspecific gravityBehaves as a projectile in motionbiology, physics, maths
22 Surface Tension Resistance to penetration & separation 3Surface TensionResistance to penetration & separationSurface acts to reduce surface areaSmallest SA to Volume ratio is offered by sphere
23 Dripping Blood 4 Blood trickles downwards Blood drop grows until Wt (G) > S.T.Single drop breaks free (teardrop shape)Surface tension pulls in verticallyAnd horizontallyShape settles into sphere (0.05 ml)Does not break up until impact
24 . . . Drop size 5 Standard drop size 50ul (0.05ml) Rapid bleeding givesslightly larger dropShaking/movementcasts off smaller drops...
25 Terminal Velocity v Distance Fallen (metric) 6Terminal Velocity v Distance Fallen (metric)
26 Terminal Velocity v Distance Fallen (imperial) 7Terminal Velocity v Distance Fallen (imperial)
28 Shape & Size of Bloodspot 9Shape & Size of BloodspotDepends mostly on nature of target surfacetexture (rough or smooth)porous or non porousSize is related to distance fallen, provided:standard 50 ul drop of bloodThere is little change in spot diameter beyond a fall distance of 1.2 m
29 Shape & Size of Bloodspot 9Shape & Size of Bloodspot
30 Hat information does this questionable drop pelt provide? 9Hat information does this questionable drop pelt provide?
31 Height Fallen10Single drops of blood falling from fingertip onto smooth cardboard from various heights.No change in diameter beyond 7 ft.Adapted fromIntroduction to Forensic Sciences,W. Eckert, CRC, 1997
32 Effect of Target Surface 11Effect of Target Surface...Spreads out smoothlyST of spreading edge isbroken by irregular surface
33 Experiments with Falling Blood Droplets 12blooddropperrulerHeightTarget SurfaceFabric (theatre green)rough paper towelpaperwhiteboardTerazzo floor
34 Single drop of blood falling from various heights (m) onto various surfaces 130.51230.5123Height/Surfacesmoothfloorpapertowelfabric
35 IMPACT ANGLE DETERMINATION ANGLE of IMPACT is the acute angle formed between the direction of the blood drop and the plane of the surface it strikes
36 Angle of Impact 14 Adapted from Introduction to Forensic Sciences, W. Eckert, CRC, 1997
37 Angle of Impact 14 Gravitational dense zone at lower edge 90 80 70 605040Gravitational dense zoneat lower edge203010Adapted fromIntroduction to Forensic Sciences,W. Eckert, CRC, 1997
38 . Wave Cast-off 15 Tail of elongated stain points in direction of travel.Tail of wave cast-off pointsback to parent dropParent dropwave cast-off
41 Point of Convergence 17 5 ml blood squirted from a syringe from height of 1 mPoint of Convergence
42 Point of Origin 1 18 Distance from point of convergence Height above point of convergenceOriginlengthwidthAngle of impact = arc sin W/L85604530
43 Tracing Origin of Bloodspots 19Tracing Origin of BloodspotsPoint of convergence method2 dimensional imagePoint of origin methodadds 3rd dimension to imageIn practice:use of string & protractor at sceneuse of computer at laboratory
45 Herbert Leon MacDonell, Laboratory of Forensic Science,P.O. Box 1111,Corning,New York,14830,USA21
46 Low Velocity Blood Spatter 22Low Velocity Blood SpatterBlood source subjected to LV impact< 5 f/s (1.5 m/s)Spot diameter: mostly mmsome smaller, some largerFree-falling drops (gravity only)Cast off from fist, shoe, weaponDrippingSplashingArterial spurting
47 Cast-off from Weapon First blow causes bleeding 23Cast-off from WeaponFirst blow causes bleedingSubsequent blows contaminate weapon with bloodBlood is cast-off tangientially to arc of upswing or backswingPattern & intensity depends on:type of weaponamount of blood adhering to weaponlength of arc
54 Cast off Pattern (2/2) ? Sequence 29Cast off Pattern (2/2) ? Sequence
55 Cast off Pattern (2/2) ? Sequence 30Cast off Pattern (2/2) ? Sequence1(4 spots)2(3 spots)3(2 spots)If weapon does not pick up more blood, spatter from subsequent backswings becomes progressively less.In practice weapon picks up more blood with each successful blow.
56 Three overhead swings with hatchet 31Three overhead swings with hatchet
78 Medium Velocity Blood Spatter 54Medium Velocity Blood SpatterBlood source subjected to MV impact( f/s, m/s)Spot diameter: mostly mmBlows with weapon (e.g. baseball bat)
79 Medium velocity blood spatter Medium velocity blood spatter. Point of impact 15 cm in front of vertical target surface556” ruler
80 Flick 1: Blood flicked between middle finger & thumb onto a vertical smooth surfacefrom a distance of 15 cmFlick 1:56
81 Flick 2: Blood flicked between middle finger & thumb onto a vertical smooth surfacefrom a distance of 15 cmFlick 2:57
82 High Velocity Blood Spatter 58High Velocity Blood SpatterBlood source subjected to HV impact> 100 f/s, 30 m/sFine mist: spot size < 0.1 mmSmall mass limits spread to 1 m!Some larger droplets reach furtherGunshotback-spatter from entry woundforward spatter from exit woundHigh speed machinery
83 Gunshot: back& forward spatter 59Bloodstained foam held just above target surface.Bullet passing L to R just above sheetbullet exits foamBullet entersfoambulletBack-spatteron entryForward spatteron exit
84 Gunshot Back Spatter Arises from entrance wound 60Arises from entrance woundPasses back towards weapon & shooterSeen only at close range of fireSeen on:inside of barrelexterior of weaponhand, arm, chest of shooter
85 Back spatter on steadying hand 61Back spatter on steadying hand
86 Gunshot Forward Spatter 62Gunshot Forward SpatterArises from exit woundPasses forwards in same direction as shotMore copious than back-spatterCan be seen at any range of fireSeen on nearby surfaces, objects, personsespecially on wall behind victim
87 Forward spatter (5 ms after bullet impacted at 1000 f/s) 63bulletblood soakedtarget2.5 cm
88 Forward spatter onto target placed 15 cm behind point of HV bullet impact (bullet passing towards screen) 1646” ruler
97 Bloodspots on trousers 78Bloodspots on trousers
98 SerologyThe analysis of the properties and effects of serums (blood, semen, saliva, sweat, or fecal matter) is called serology.
99 Immunoassay techniques Looking for Drugs, toxins, antibodiesAntibodies not found in humans are synthesizedUsually inject compound with drug (that you are testing for) into an animalWhy????Animal makes antibodies because it is a foreign substance
100 Immunoassay techniques Enzyme Multiplied Immunoassay Technique (EMIT): Detection of drugs through a antigen-antibody reaction.Radioimmunoassay (RIA) uses drugs that are labeled with radioactive drugsSO DETECTION occurs with any other related forms of that drug type!!!
101 Immunoassay techniques ~~EMIT screening Add subjects urine antibodies to detect material.For methadone: add methadone antibodies to the urine. [Conc] of antibodies not used indicates concentration used by the drug providing a related methadone concentration
102 Immunoassay techniques, ~~EMIT screening Marijuana's major active agent THCTetrahydrocannabinol (3- 4.5%)Liquid Hashish oil 8-22 %THC Metabolized into THC-9-carboxlic acidIs detectableTHC-9 in smokers urine is<1 mg (millionth of a gram)2-5 days…10 days (sometimes)
103 Animal Responses:Polyclonal antibodies: antibodies produced by injecting animals with a specific antigen . A series of antibodies.A series of antibodies are produced responding to a variety of different sites on the antigen.Monoclonal Antibodies: collection of identical antibodies that interact with a single antigen n site.Mass produced by HYBIDOMA CELLS: spleen-cancer hybrids made in limitless supply
105 It’s Red so it must be blood, right? When found at a CS, you must determine:If it is blood?Human vs animal.How closely it can be associated with a specific individual?
106 Crime Scene analysis of blood Confirming the stain is blood(Presumptive tests)LuminolKastle Meyer testLeukomalachite greenHemastix ®Confirming the blood is HUMANELISA/Precipitin test
107 Presumptive tests:A simple test for a given substance using a reagent that changes color when mixed with the substance under investigation.Presumptive tests are not definitive and further confirmatory tests are always required. They are used extensively in forensic science.In general analytical chemistry, presumptive tests are often called spot tests.The first test is simply the use of a powerful light moved across every surface of a crime scene. That yields possible traces for visual inspection.
108 1. Luminol Luminol Reagent: Tests for by production of light rather than color.Extremely sensitive and can detect minute amounts of bloodDOES NOT interfere with subsequent DNA analysis
110 1. Luminol Reaction RBC contain hemoglobin Mix luminol + Peroxide The iron in homoglobin acts as a catalyst speeding up the reaction between Peroxide and luminol.As reaction progresses, light is generated for about 30 seconds(room should be dark)
111 1. Luminolsprayed across the scene because it reacts to blood by making it luminescent. It only takes about five seconds. The procedure requires that the room be considerably darkened in order to see the faint bluish glow, and the intensity of the glow increases proportionately to the amount of blood present. It works even with old blood or diluted stains, and can illuminate smear marks where blood has been wiped away. However, there is one problem with this test: luminol can destroy the properties of the blood that investigators need for further testing. Its use is limited to proving that blood is present even if not visible.
112 2. The Kastle-Meyer Color Test uses a solution of phenolphthalein and hydrogen peroxide on a piece of filter paper, and when blood of any quantity is present, it turns pink. However, it also turns pink in the presence of potatoes or horseradish, so care must be taken at the scene.
113 Characterization of blood stain 3. Hemastix ® is a dipstick for bloodMoisten with distilled water and dipped into the samplePositive presence of blood detected if stick turns green
114 Characterization of blood stain 5. Precipitin Tests: (10-15 years)Serum for the precipitin test is obtained from rabbits which have produced antibodies to destroy a small quantity of human blood injected into them. A drop of this anti-human serum is added to suspect blood, which will precipitate its protein if it is of human origin.Electrophoretic method: ??Western blotting test... analysis can detect one protein in a mixture of any number of ... Western blotting tells you how much protein has accumulated in cells
115 Precipitin Tests: history Investigators use the precipitin test to determine whether the blood is of animal or human origin. German biologist Paul Uhlenhuth discovered that if he injected protein from a chicken egg into a rabbit, and then mixed serum from the rabbit with egg white, the egg proteins separated from the liquid to form a cloudy substance known as precipitin. In other words, it forms an antibody. In the forensic test for human blood:either a sample of the suspect blood is put into a test tube over the rabbit serum or it's used in the "gel diffusion" test, where it's placed in gel on a glass slide next to a sample of the reagent (anti-human serum). Passing an electric current through the glass, the protein molecules filter into the gelatin and toward each other. A line forms where they meet---called a precipitin line---that means the sample is human blood.
116 Precipitin Tests: history In 1925, another blood-related discovery important to criminal investigation was made. Around 80 percent of the human population were found to be "secretors," which means that the specific types of antigens, proteins, antibodies, and enzyme characteristic of their blood can be found in other bodily fluids and tissues. In the case of a secretor, investigators can tell the blood type by examining the saliva, teardrops, skin tissue, urine, or semen.In a rape case, for example, where the perpetrator is a secretor, potential suspects can be narrowed down through blood type analysis
117 Characterization of blood stain 5. ELISA/Precipitin Test: Human Antiserumdetermines if blood is from animal or human origin.HOW does it work?Remember ANTIGEN-Antibody Reaction???????