by Tricia Psarreas Murray

Created on: June 13, 2009   Last Updated: July 02, 2009

When someone commits a gun crime, it is nearly impossible to catch them without solid firearm evidence at the crime scene. Witnesses are helpful, but they cannot convey the truth like science does. Thankfully, in today's crime scene investigation world, there are more than enough ways to accurately solve a crime using firearm evidence.

The first thing that can help link a person to a crime is a bullet comparison. As a bullet passes through the barrel of a gun, its surface picks up the impressions from the barrel. Since no two barrels have identical markings, it is easy to determine whether or not a bullet was fired from a certain gun once test firings have been shot for comparison. If the bullet was not fired from the same gun, the weapon in question is ruled out of the investigation. However, if the gun is a match, a case may very well be solved.

Crime scene investigators and forensic specialists can also obtain evidence by examing cartridge cases. When a gun is fired, a cartridge case is discarded. These cartridge cases can be linked to a particular gun by examining markings from the firing pin, the breechblock, the firing chamber, the extractor, and the ejector marks. These markings can also be present on the surface of the brass part of the shells. As is the situation with bullet comparisons, cartridge case evidence can make or break a case.

The third thing that makes it easier to collect firearm evidence is automated firearm search systems. These make it possible to store bullet and cartridge characteristics in a database that can be used to compare past and current firearm evidence. This is a wonderful system because it allows crime laboratories to share information that could link crimes together, solve past or recent crimes, and identify the owner of the gun in question.

Finally, firearm evidence can be analyzed through the use of serial number restoration. When a gun is made, it is impressed with a serial number. These numbers are often scratched off to avoid the chance of linking the gun to a crime. If an etching agent is applied to the area where this number is located, the etched pattern will show the original numbers. If this works properly, the numbers will be restored and the gun's origins will be known.

By applying these crime scene investigation principles to their searches, specialists have a much better chance at collecting firearm evidence and solving cases. All a jury needs to crack a case is a suspect and some indisputable evidence. On that end, technology has come a long way and with it, so has justice.

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