The document summarizes different types of bloodstain patterns and what they can reveal about crime scenes. It describes how bloodstains from low, medium, and high velocity impacts have different characteristics depending on the force and can provide information about weapons, the number of blows, and the positions of victims and assailants. It also discusses patterns from dripping, splashing, arterial spurting, gunshots, transfers, wipes, and flows.

4. Dripping Blood Blood drop grows until Wt (G) > S.T. Single drop breaks free (teardrop shape) Surface tension pulls in vertically Shape settles into sphere (0.05 ml) Does not break up until impact And horizontally Blood trickles downwards 4

5. Drop size . Standard drop size 50ul (0.05ml) . Rapid bleeding gives slightly larger drop Shaking/movement casts off smaller drops . 5

6. Terminal Velocity v Distance Fallen (metric) 6

7. Terminal Velocity v Distance Fallen (imperial) 7

8. Free Falling Blood Droplets 8 . 50 ul 4.6 mm 7.5 m/s 4.2 to 5.4 m 0.5 ul 2.12 mm 2.4 to 3 m . 4.6 m/s 0.12 ul 1.32 mm 0.84 to 1 m . 3.3 m/s 0.06 ul 1.1 mm 0.5 to 0.65 m . 2.2 m/s

10. Height Fallen Single drops of blood falling from fingertip onto smooth cardboard from various heights. No change in diameter beyond 7 ft. Adapted from Introduction to Forensic Sciences , W. Eckert, CRC, 1997 10

11. Effect of Target Surface . . Spreads out smoothly ST of spreading edge is broken by irregular surface 11 . . . .

12. Experiments with Falling Blood Droplets Terazzo floor whiteboard rough paper towel paper Fabric (theatre green) Height Target Surface 12 blood dropper ruler

13. Height/Surface Single drop of blood falling from various heights (m) onto various surfaces smooth floor paper towel fabric 13 0.5 1 2 3 0.5 1 2 3

14. Angle of Impact Adapted from Introduction to Forensic Sciences , W. Eckert, CRC, 1997 Gravitational dense zone at lower edge 14 90  10  70  20  30  60  50  40  80 

15. Wave Cast-off David Sadler: 15 . Parent drop wave cast-off Tail of wave cast-off points back to parent drop Tail of elongated stain points in direction of travel

16. Point of Convergence 16

17. Point of Convergence 5 ml blood squirted from a syringe from height of 1 m 17

18. Point of Origin length width Angle of impact = arc sin W/L 18 1 Distance from point of convergence Height above point of convergence Origin 85  60  45  30 

21. Herbert Leon MacDonell, Laboratory of Forensic Science, P.O. Box 1111, Corning, New York, 14830, USA 21

24. Downswing of Hammer 24

25. Cast-off from Weapon ceiling 25

26. Overhead swing with bloodied metal bar 26

27. Cast-off Pattern (1/2) 27

28. Cast off Pattern (2/2) 1 2 3 28

29. Cast off Pattern (2/2) ? Sequence 29

30. Cast off Pattern (2/2) ? Sequence 1 (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. 30

31. Three overhead swings with hatchet 31

32. Cast-off & medium velocity spatter 32

33. Cast-off & medium velocity spatter 2 33

34. Cast-off Pattern ? Object 34

35. Cast-off Pattern from Hand 35

36. Cast-off pattern from bloodied hand swung in front of target 6” ruler 36

38. Drip 1: Blood dripping into itself from height of 1 m (8 drops) 38

39. Drip 2 Blood dripping into itself from height of 1 m (8 drops) 39

40. Dripping onto steps 40

42. Splash 1 5 ml blood squirted from a syringe from a height of 1 m 42

43. Splash 2 5 ml blood squirted from a syringe from a height of 1 m 43

44. Splash 3 5 ml blood squirted from a syringe from a height of 1 m 44

45. Splash onto vertical surface 6” ruler 10 ml blood thrown 1 m onto a vertical target surface 45

46. Stamping in blood 1 Area seen in close-up in next slide 46

47. Stamping in blood Close-up of heel area 47

48. Stamp 1 Blood pool (10 drops) before stamping 48

49. Stamp 2 Blood pool (10 drops) after stamping 49

51. Small arterial spurt spatter broken pottery 51

52. Neck incisions (scene) 52

53. Neck incisions Thyroid cartilage Probe in carotid artery ‘ Hesitation’ injuries 53

55. Medium velocity blood spatter. Point of impact 15 cm in front of vertical target surface 6” ruler 55

56. Flick 1: Blood flicked between middle finger & thumb onto a vertical smooth surface from a distance of 15 cm 56

57. Flick 2: Blood flicked between middle finger & thumb onto a vertical smooth surface from a distance of 15 cm 57

59. Gunshot: back& forward spatter Bloodstained foam held just above target surface. Back-spatter on entry Forward spatter on exit Bullet passing L to R just above sheet 59 bullet Bullet enters foam bullet exits foam

61. Back spatter on steadying hand 61

63. Forward spatter (5 ms after bullet impacted at 1000 f/s) blood soaked target bullet 63 2.5 cm

64. Forward spatter onto target placed 15 cm behind point of HV bullet impact (bullet passing towards screen) 1 6” ruler 64

65. Forward spatter (closer view) 65

66. Forward spatter (closest view) 5 mm 66

69. Transfer from hair (hair-swipe) 1 69

70. Transfer from hair (hair-swipe) 2 70

72. Flow pattern 72

73. Trapped! 73

74. Stabbing 1 74

75. Stabbing 2 75

76. Blood flow on shirt Horizontally to R side 76

77. Pattern on shirt 77

78. Bloodspots on trousers 78