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Police Department

Firearms and Tool Mark Unit

Role: The Firearm and Tool Mark Identification Unit (FTIU) provides the comparative forensic analysis of evidence submitted from incidents involving firearms. This is accomplished primarily by the microscopic examination of fired bullets, cartridge cases and/or other ammunition components to determine whether they were fired by a particular firearm.

firearms examiner using a comp scope

In addition to the microscopic examination of ammunition components, the FTIU is also responsible for the following:

  • Muzzle to Target Distance Determination Examinations, which involves the process of determining the distance of the firearm’s muzzle to the target based upon patterns of gunpowder or gunshot residues deposited upon that target.
  • Restoration of obliterated serial numbers through the application of scientific techniques.
  • Function Testing of Firearms, which involves the examination of a firearm’s mechanical condition and operation to determine if all safety features are operable and/or if the firearm is capable of firing a cartridge.
  • Tool Mark Examinations to determine if a tool mark was produced by a particular tool.
  • National Integrated Ballistic Information Network (NIBIN).  Cartridge cases collected from scenes and test fired cartridge cases from firearms are entered into NIBIN to establish potential links, or “Hits,” between multiple crime scenes where the same firearm was used.

Some of the Instruments used:

  • Comparison Microscopes
  • NIBIN BrassTrax Acquisition Units and MatchPoint Correlation Units
  • Stereo Microscopes
  • Bullet Recovery Water Tank
  • Indoor Shooting Range
  • Alternate Light Source

Hits generated through NIBIN are currently being used by local (MNPD), State and Federal Law Enforcement agencies to assist in the investigation of multiple shooting incidents. The MNPD Crime Laboratory Firearm and Tool Mark Identification Unit has one of the most successful NIBIN programs in the United States.

Don Carman

Additional Staff: 5 Forensic Scientists and 4 NIBIN Technicians