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Blood Spatter
The first recorded references to blood-spatter analysis date back to
1894, when a little-known scientist named Eduard Piotrowski made
notes about the possible use of blood-spatter patterns in solving
a crime. Few investigations actually utilized this hypothesis until
1955, when Dr. Paul Kirk used bloodstain analysis as part of the
defense case in the famous Sam Sheppard murder trial. The well-
documented murder case, which dominated the newscasts for a
year, inspired the movie The Fugitive.
Surface Matters:
Hard vs. Soft Surfaces
Blood does not act the same way when it falls on all surfaces; what matters
is how porous the surface is. There is a spectrum of surface types that are
commonly found at crime scenes, each with a different effect on droplet
formation. It is the job of a forensic expert to know the differences. If the
surface is very smooth and nonporous, like glass, blood usually stays in a
relatively tight drop on the surface. The surface tension of the blood keeps
it together. If the surface is porous, like brick, the blood droplet tends to
break up more on impact. In this case, the outer edges of the droplet will
look more ragged and variable. Blood droplets with smooth edges are the
result of impact with a smooth, nonporous surface.
A floor covering such as linoleum usually results in a slight splashing
outward of the blood. Linoleum is slightly porous, so it causes more edge
