Firearms and Toolmarks

The Firearms and Toolmarks section of the forensic laboratories performs a variety of functions for law enforcement agencies throughout Allegheny County.

Firearms

Scientists assigned to this section perform a routine operation and safety inspection before test firing each firearm. The test cartridge cases from select caliber firearms are entered into the National Integrated Ballistic Information Network (NIBIN) system. If a serial number has been obliterated from a firearm, serial number restoration may be possible.

NIBIN

Through the NIBIN program, the Bureau of Alcohol, Tobacco, Firearms and Explosives deploys Integrated Ballistic Identification System (IBIS) equipment to federal, state and local law enforcement agencies for their use in imaging and comparing cartridge case evidence and test standards. The goal of NIBIN is to discover links between crimes more quickly.

Fired Ammunition Components

Discharged bullets, cartridge cases and shotgun shell cases are classified and, if they have sufficient detail, they are microscopically compared to other fired components or test fires.

Distance Determination

Articles of clothing are examined for any firearms-related evidence such as bullet holes, soot or smoke, gun powder particles, ripping/tearing and bullet wipe. It may be possible to make a muzzle-to-garment distance determination by examining a gunshot residue pattern and/or the shot pellet pattern on the clothing and comparing it to test patterns produced using the suspected firearm.