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Case Linkage

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Forensic firearm laboratories maintain files of fired evidence bullets from unsolved cases. This facilitates the possibility that linkages can be made between shooting incident cases involving serial shooters. It is known that a small percentage of the criminal population commits a large percentage of crimes; this also applies to firearms-related crime. Case linkages may be determined by examining fired bullets recovered from the bodies of victims or from crime scenes. This includes bullets from cases in which a firearm has not been located or connected to the evidence collected at the crime scene.

Bullets submitted to the laboratory are microscopically compared to all previous bullets of the appropriate caliber retained in physical files. These files may be referred to as unsolved case files, open case files, reference fired specimen files, or open case ammunition files.

Over time, open case files grew large and became difficult to use in many laboratories. This process was simplified by advances in technology that allowed for digital searches of files to identify potential case linkages based on high probability associations. However, final confirmation of a linkage still requires comparison by an examiner using a comparison microscope.

These technological advances resulted in a system for accomplishing these computer-based comparisons or correlations - the Integrated Ballistics Identification System (IBIS).

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