Jordana Cheyenne Singh, Gregory J Williams

In the Caribbean region, most housing projects have transitioned from the use of concrete to drywall surfaces for building construction. When a bloodshed event happens at a crime scene, it will result in an impact blood spatter pattern on various surfaces. The main aim is focused on investigating the appearance and directionality of bloodstain patterns on drywall surfaces to reconstruct the events where the bloodshed happened. The objectives were to determine how the drywall surface influences the sizes and shapes of the bloodstains and to reconstruct the area of origin on the vertical drywall surface by using the manual stringing technique. An experimental study utilizing 800 mL of porcine blood was conducted. The blood dropped at various distances and angles showed scalloped margins and many satellites as it impacted the drywall surface. As the angle decreased from 90 degrees, it developed an elliptical form. Directionality was also evident with increased speed over a distance of 16 feet along the drywall surface. Medium-velocity spatter patterns were created on drywall and cardstock control surfaces at heights of 20 cm, 68 cm, and 150 cm. The stringing method was used to study the directionality of these bloodstain patterns on drywall. The ellipticity was used in the calculations of the impact angle, and the area of origin was calculated using trigonometry. The calculated X values that represented the distance of the blood source away from the wall were 22.25 cm, 58.88 cm, and 139.61 cm. The estimated heights (Z) of the blood source were 24.50 cm, 76 cm, and 161.40 cm. The Z-estimated values were overvalued due to the neglect of gravity and drag. The gamma angles were measured and showed that the rounder stains presented a greater degree of uncertainty than the elliptical stains.
Keywords: drywall; cardstock; directionality; medium velocity spatter; impact angle; area of origin; ellipticity; blood spatter