Video Presentations

Firearms and Tool Mark Evidence

Collecting and Packaging Firearms

This video demonstrates the proper way to make a pistol safe and the proper way to collect and package a firearm.

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Casting Tool Mark Impressions with Mikrosil

Learn how to cast a tool mark impression with Mikrosil casting material.

Matching Crime-Scene Bullets Segment by Segment

When a bullet is fired from a gun, the barrel leaves distinctive scratch marks on the surface of the bullet. These microscopic marks are highly similar for bullets fired from the same gun, meaning they can be used for forensic comparison, matching bullets taken from a crime scene to a particular gun. However, crime-scene bullets are often deformed from collisions, which can make direct comparison difficult. Now, NIST researchers have developed a new algorithm that makes this matching more accurate, by dividing the markings on the deformed bullets into segments, and correlating those segments with the reference bullet. Credit: Sean Kelley/NIST