Blood droplet dynamics and its forensic implication in crime scene investigation
Shahid Iqbal, Akhtar Ali, Muhammad Ashraf Tahir, Muhammad Haleem Tayyab, Muhammad Imran, Khalid Sajjad Feras · Forensic Research & Criminology International Journal · 2018
\tA technique of calculating the origin of blood and trails formed at the crime scene that could give impact directions and positions had been presented in this paper. The size of bloodstains, the volume of droppers, and spikes around the stain border relayed on droplet impact velocity and droplet diameter. It was not unusual to find bloodstain patterns in a violent encounter, and through proper interpretation they could provide very critical facts about such an incident. Precise measurements and digital camerawork might estimate the free height of passive droplets, the features related to the effect of the surface, and the intensity involved in bloodshed. Four diverged forms of stains were made and human blood with heparin as an anti-coagulant was taken. The blood volumes taken were: 10 ï l, 5 ïl, 1ï€l, 0.5ï, 0.25ï, and 0.1ï€l. Pipette (Eppendorf) and precision syringe were applied for computing and discharging the blood splashing. Blood droplets were permitted to fall freely by hand by pressing the needle of the syringe very gently so that drops were detached from the tip of a stainless steel hypodermic needle at their own form. Individually, all volumes were cycled for successively for five times to make four kinds of contact stains and spatter stains on different surfaces used. The results were deduced through Regression Coefficient Relation, One-Way ANOVA and Two-Way ANOVA which showed significance statistically. The resulting stains were than examined and photographed with digital camera.