Firearm & Toolmarks


About Us

The Firearm and Toolmark Identification Section of the laboratory examines firearms for operability, and examines and microscopically compares bullets, cartridge cases, and shotshells to determine if they were fired from or in a particular​ firearm. By test firing the firearm and recovering the known fired bullets and cartridge cases, a comparison can be made with the submitted evidence. The comparison is performed using a comparison microscope, which is basically two microscopes connected by an optical bridge that allows the examiner to view two objects simultaneously under the same magnification. This allows the examiner to view unique microscopic imperfections placed on the evidence and test fires by the firearm that fired them.

Another area of analysis is the examination and comparison of toolmarks left at a crime scene to determine if they were produced by a particular tool. For example, a pair of bolt cutters used to cut a lock at the scene of a crime will often leave unique microscopic striations and/or impressed defects on the lock's cut surface, that can later be used to identify the suspect's bolt cutters. Screwdrivers, pliers, crow bars, hammers and the like, can leave unique marks on surfaces at crime scenes.

Other examinations performed in the Firearm/Toolmark Section include, but are not limited to, examining and processing of obliterated serial/VIN numbers on firearms, motor vehicles and ATV's in order to restore them, examining clothing and other objects for gunpowder residue patterns or shot pellet patterns in order to determine the distance a firearm was from the victim/target at the time of the shooting, ​and shooting scene reconstruction/ trajectory analysis, and footwear/ tire impression examinations.

Educational Requirements

Baccalaureate or advanced degree in chemistry, biology, biochemistry, molecular biology, forensic sciences, natural sciences, or related field.​

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