Steps when 3 or more blood stains are present:
(1) Determine the impact angle for the individual blood stains.
(2) Extend a line through the long axis of each blood stain.
(3) Identify the point where the extended lines intersect.
(4) Measure the distance from the closer edge of the blood stain to the point of convergence.
Parameters:
(1) distance of a particular stain from the convergence point in cm
(2) impact angle for the stain in degrees
impact angle in degrees =
= (height for the point of origin above the surface) / (distance from stain to convergence point)
height for the point of origin above the surface in cm =
= TAN(impact angle) * (distance in cm)
Limitations:
• The point of convergence can be best be estimated when the stains radiate out in several directions. If the stains are close together then the estimate may be subject to more error.
• The assumption is that all of the stains were made at the same time from the a single event. Multiple events or a moving source may make the estimates inaccurate.
