1. Firearms & Toolmarks
Chapter 9

2. Toolmark
Scratch or other marking left by the action of a tool on an object
Firearm identification
Breaking and entering doors and windows
Impression on the edge of a cut wire

3. Firearms Identification
Forensic ballistics
Firearms examinations (study of projectiles in motion)
Wound ballistics
Gunshot residue
Serial number restorations
Estimate distance gun was shot

4. Firearms Pistols/handguns (revolvers and self-loading) Rifles
Machine guns
Submachine guns
Shotguns
All firearms except shotguns use bullets that can be compared based on rifling patterns (grooves/striations)

5. Firearm Evidence
Trace evidence collected first from the surface of the weapon
Bullet and cartridge comparisons performed by matching striations (rifling)
Bullet caliber also determined
Striations may not always match if gun is rusted
Trace evidence: Fingerprints, gunshot residue, fibers, hairs

6. Firearm Evidence Continued…
Gunshot residue pattern
Distance shot- no residue left on victim (greater than 18 inches away)
Close range- residue left on victim
Contact shot- muzzle of gun in contact with victim

7. Distance shots have bullet holes with rounded edges
Distance does not impact size of bullet hole
Close range shots cause stippling patterns on victim
Shotgun shots
Gun shot pattern increases with distance

8. Other toolmarks…
Matched by creating cast of suspect’s tool to the toolmark at the scene