What can analysis of firearm tool marks reveal?

The analysis of firearm tool marks can provide critical insights into the specific firearm used in a crime scene. Every firearm has unique characteristics caused by manufacturing processes and wear over time that leave distinctive markings on the bullets and cartridge casings when fired. Forensic experts can compare these markings to those from known weapons in a database or from weapons recovered in investigations. This comparison can link bullets or casings found at a crime scene to a particular firearm, thereby helping investigators establish connections between the weapon and the suspect or victim.

While other options relate to important aspects of forensic investigation, they do not directly pertain to the identification of the firearm itself. Determining the distance from which a shot was fired, the type of bullet used, or the number of shots fired involves different forensic techniques and analyses, such as gunshot residue testing or ballistic calculations, rather than the direct examination of the firearm's unique tool marks.