The primary function of the Firearm and Toolmark examiner is to determine whether a bullet, cartridge case, or other ammunition component was fired in or cycled through a specific firearm to the exclusion of all other firearms. While the comparison of ammunition components to firearms is the main role of the Firearm and Toolmark Section, it also provides many other services, to include:
- Firearm Function Testing
- General Rifling Characteristics
- Distance Determination
- Serial Number Restoration
- NIBIN(National Integrated Ballistic Information Network) Database Entry / Searching)
- Operation Shutdown (test firing and NIBIN Database entry)
- Toolmark Examination
- Fracture Matches
After each case is worked, an examiner will issue a detailed report concerning scientific findings related to the Firearm and Toolmark analysis. Then, upon request, the examiner will testify in criminal proceedings based upon these findings as an expert witness in the area of Forensic Firearm and Toolmark examinations.
The NIBIN database allows the Firearm and Toolmark Examiners to input images of cartridge cases recovered from the scene of a crime as well as cartridge cases test fired in recovered firearms. As new images are entered, the system will search for possible matches to previously entered cartridge cases. When a possible match is found, a firearms examiner will conduct a microscopic examination of the evidence to determine if there is a match.