The students in the photos, Porschia Mitchell and Stefanie Waters were using the “string” method to approximate the three-dimensional space or location of a blood source at the time it was impacted by an external force.  The students first determined the two-dimensional area of convergence to determine approximately where (on the floor) the blood source was at the time of the bloodletting event.  They did so by drawing lines through the long axes of the bloodstains and noting where those line converged on the floor.  In that area of convergence they placed a tripod which represented the “victim.”  The students then measured the width and length of the blood stains and through a trigonometric equation were able to determine the angle of deposition (the angle in which the blood was traveling when it struck the surface) of the blood stain.  A protractor was used to run a string (representing the path of the blood droplet) from the surface at the specific angle to the appropriate height on the tripod, creating a three-dimensional representation along the “z” axis.  This area of origin is the approximate height of the blood source at the time it was impacted by an external force.

FI blood splatter Feb. 2016 (2)