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Table 3. Ratio difference between top and bottom zone of each bloodstain.

Table 3 Ratio difference between top and bottom zone of each bloodstain.

Related Figures (21)

Figure 1. A 12 x 12 cm wooden frame sprayed with heat enamel spray paint to make ballistic gel mould.
Figure 1. A 12 x 12 cm wooden frame sprayed with heat enamel spray paint to make ballistic gel mould.
Figure 2. The liquid ballistic gel in the wooden frame showing the 5 x 5 cm wood chamber piece and the parchment paper underneath the ballistic gel. The bottom right shows a picture of the L-shaped jig used to find the centre of each mould. Figure 2. The liquid ballistic gel in the wooden frame showing the 5 x 5 cm wood chamber piece and
Figure 2. The liquid ballistic gel in the wooden frame showing the 5 x 5 cm wood chamber piece and the parchment paper underneath the ballistic gel. The bottom right shows a picture of the L-shaped jig used to find the centre of each mould. Figure 2. The liquid ballistic gel in the wooden frame showing the 5 x 5 cm wood chamber piece and
Figure 3. An enclosed ballistic gel mould with the closed chamber pocket (centre darker square).
Figure 3. An enclosed ballistic gel mould with the closed chamber pocket (centre darker square).
Figure 4. Ballistic gel mould with blood placed in its securing gel block.
Figure 4. Ballistic gel mould with blood placed in its securing gel block.
Figure 5. Overall methodology in situ from trial 10 cm at 60°, paper target rig (far right), gel block stand (middle), and ransom rest (left).
Figure 5. Overall methodology in situ from trial 10 cm at 60°, paper target rig (far right), gel block stand (middle), and ransom rest (left).
Figure 6. Ransom rest mechanism used to hold the gun at a controlled height and level.
Figure 6. Ransom rest mechanism used to hold the gun at a controlled height and level.
Figure 7. Syringe injecting the 6 mL of blood into the enclosed chamber of the ballistic gel Using a medical syringe, 6 mL of sheep’s blood was injected into the gel block chamber creating a centralized pocket of blood within the mould. Figure 7 displays the medica syringe injecting the sheep’s blood into the ballistic gel mould. A narrow medical syringe was used because the needlepoint is small and would create a narrow opening within the gel mould. This ensured that the path of least resistance would be the bullet hole anc not the incision made by the needle. Preliminary testing proved this to be a reliable and repeatable method.
Figure 7. Syringe injecting the 6 mL of blood into the enclosed chamber of the ballistic gel Using a medical syringe, 6 mL of sheep’s blood was injected into the gel block chamber creating a centralized pocket of blood within the mould. Figure 7 displays the medica syringe injecting the sheep’s blood into the ballistic gel mould. A narrow medical syringe was used because the needlepoint is small and would create a narrow opening within the gel mould. This ensured that the path of least resistance would be the bullet hole anc not the incision made by the needle. Preliminary testing proved this to be a reliable and repeatable method.
Figure 8. Example of the Photoshop analysis zoomed at 200%. There is evidence of 10 bloodstains less than 1 mm (black circles). That square was counted toward the total area. This research investigates how bloodstain pattern size is affected by distance and orientation; therefore, observing the densest part of the misting pattern was found to be the most efficient method. Density was defined as how many bloodstains (less than 1 mm in diameter) fit within a 1 cm square; the criteria for inclusion of a dense forward-spatter misting pattern was established as ten or more stains in a 1 cm square. Figure 8 displays an example of the photoshop analysis using the criteria of inclusion.
Figure 8. Example of the Photoshop analysis zoomed at 200%. There is evidence of 10 bloodstains less than 1 mm (black circles). That square was counted toward the total area. This research investigates how bloodstain pattern size is affected by distance and orientation; therefore, observing the densest part of the misting pattern was found to be the most efficient method. Density was defined as how many bloodstains (less than 1 mm in diameter) fit within a 1 cm square; the criteria for inclusion of a dense forward-spatter misting pattern was established as ten or more stains in a 1 cm square. Figure 8 displays an example of the photoshop analysis using the criteria of inclusion.
Figure 9. (a) Bloodstain image without levels adjusted; (b) bloodstain image with levels adjusted.
Figure 9. (a) Bloodstain image without levels adjusted; (b) bloodstain image with levels adjusted.
Figure 10. Image of a bloodstain pattern (20 cm at 60°), scaled with the guides (pink) and 1 cm grid displaying the four zones.
Figure 10. Image of a bloodstain pattern (20 cm at 60°), scaled with the guides (pink) and 1 cm grid displaying the four zones.
Figure 11. (a) Example of the beginning result; (b) end result of the same bloodstain pattern (20 cm at 60°) to calculate the total area. There is an example of excess blood that was not used for the dense pattern estimation (bottom left).
Figure 11. (a) Example of the beginning result; (b) end result of the same bloodstain pattern (20 cm at 60°) to calculate the total area. There is an example of excess blood that was not used for the dense pattern estimation (bottom left).
Figure 12. Total area of each trial at 90°; in total, there were three trials at each distance.
Figure 12. Total area of each trial at 90°; in total, there were three trials at each distance.
Figure 13. Total area of each trial at 60°; in total, there were three trials at each distance, except there were 4 trials at 60°.
Figure 13. Total area of each trial at 60°; in total, there were three trials at each distance, except there were 4 trials at 60°.
Figure 14. Total area of each trial at 30°; in total, there were three trials at each distance, except there are no values at 10 cm due to equipment restrictions.
Figure 14. Total area of each trial at 30°; in total, there were three trials at each distance, except there are no values at 10 cm due to equipment restrictions.
Figure 15. The average area at each distance from a perpendicular angle to the floor (90°).
Figure 15. The average area at each distance from a perpendicular angle to the floor (90°).
Table 1. Average area of each bloodstain.
Table 1. Average area of each bloodstain.
Figure 16. Average total area at all three angles (30°, 60°, and 90°) at all four distances (10, 20, 40, and 80 cm). Note that 10 cm distance at 30° was not able to be tested due to physical limitations.
Figure 16. Average total area at all three angles (30°, 60°, and 90°) at all four distances (10, 20, 40, and 80 cm). Note that 10 cm distance at 30° was not able to be tested due to physical limitations.
Table 2. Linear regression analysis results for the average area at each angle. 4.2. Vertical Symmetry
Table 2. Linear regression analysis results for the average area at each angle. 4.2. Vertical Symmetry
Ratio Between the Symmetery of Top and Bottom Zones at 90°
Ratio Between the Symmetery of Top and Bottom Zones at 90°
Table 4. Linear regression analysis results on the vertical symmetry at each angle. 4,3. Elliptical Bloodstain Observations
Table 4. Linear regression analysis results on the vertical symmetry at each angle. 4,3. Elliptical Bloodstain Observations
Figure 18. Graph of the ratio between the top and bottom zones at each distance and angle. ' No data were collected due to equipment interferences between the ballistic gel and paper target.
Figure 18. Graph of the ratio between the top and bottom zones at each distance and angle. ' No data were collected due to equipment interferences between the ballistic gel and paper target.
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