Firearm and Toolmark analysis involves the analysis of the marks produced on one item by another item, such as a firearm or a tool. In regards to firearm analysis, the items with the marks generally include bullets, cartridge cases, shot shells, or other ammunition components. Toolmarks can be pry marks, cut marks, or other types of marks depending on the type of tool.
Firearm and Toolmark analysts at the Kern Regional Crime Laboratory examine evidentiary firearms to determine their class and unique individual characteristics for identification purposes as well as their functionality. Individual rifling characteristics of a firearm are imparted to the surface of a bullet as it travels down the barrel. The individual characteristics of the firing pin, breech face, extractor and ejector are imparted to the surface of the cartridge case when it is fired, depending on the type of firearm. Using the Firearm Database Search, firearm examiners are able to acquire, digitize, search and sort images of spent cartridge casings and bullets from crime scenes and seized evidence.
Serial numbers are another type of toolmark. Many valuable items manufactured today have serial numbers for identification. The application process of many serial numbers changes the material immediately surrounding the number. Serial numbers are removed or obliterated in a variety of ways. Analysts use various techniques to attempt to restore the serial number.
Fracture match analysis is the examination of two or more objects to determine if a broken, torn, or cut material and other pieces were once a single unit. Analysts document and evaluate items with various lighting and comparison techniques to reach their conclusions.