Chelsia Stone
October 7, 2012
Practical 5
In the practical on Tuesday we worked with bullet trajectory. We were paired into new
groups and had to rotate to four different stations to analyze their trajectory.
In order to accurately determine a bullets trajectory there must be both an entry and exit
point. From there a rod, made of either wood or metal, can be placed through the bullet holes.
However, if the bullet hole is not large enough to fit the rod then it is not possible to accurately
determine trajectory with this method. I would also like to note that the entry point of a bullet
will have edges that point inward toward whatever was struck rather than outward. The exit point
will have noticeably more severe damage than the entry point.
The crime scene analyst must the take photographs of the bullet holes. This includes a far
away, or overall view. The a midrange view, showing the bullet holes in relation to other bullet
holes in the vicinity. Finally, a close-up shot must be taken of the bullet holes, both with and
without a small scale placed next to each one.
After the pictures are taken, a crime scene analyst must measure the height the bullet hole
is from the ground. This can be done using a normal tape measure and measuring to the middle
of the entry point hole. Then to determine the up-down angle a carpenter’s level is used. The
level is placed underneath the rod, and up to the bottom of it. This will give the angle the bullet
was fired at compared to the ground. An angle of 90 degrees must always be the one used and
the analyst must note whether the bullet at an up or down angle. This shows if the shooter was
shooting downward, say from a building, or upward, say from a position laying on the ground.
Then the analyst must also take the angle to which the bullet was shot from either the left or
right. This is done by using a special measure, must like a protractor. However, instead of
starting at a 0 degree angle the instrument starts at a 90 degree angle. Like the measurement
before the angle must be below 90 degrees and it must be noted if the angle corresponds to the
left or right. When put together both the angles collected can give an approximate placement of
where a shooter was standing when any bullets were fired.
The analyst must make sure to record all of this information carefully in their notes. This
ensures that the crime scene can be recreated at anytime and that all measurements are properly
recorded and not forgotten.
young, T., & Ortmeier, P. J. (2011). Crime scene investigation. New York, NY: Prentice Hall.