UNIT 9: CH's 16 & 17: TOOL MARKS/BALLISTICS
Tool marks...some of the more common pieces of evidence left behind at a crime scene by suspects. All tools, unique or mass produced, leave a characteristic marks that can be used to identify them. They can make indentation marks, abrasion marks, or cutting marks. As with all evidence, the first then an investigator should do is to photograph the evidence, both the tool and the mark it left behind, in order for comparison later in the lab. Casts could also be done of tool marks in order to match the mark to the proper tool. Like fingerprints, investigators have access to an image database for tools to help them link tools and tool marks to suspects or crime scenes.
Firearms also leave distinctive marks,only they leave them on the bullets when they are fired. These marks help forensic investigators match bullets to the barrel of the gun that fired it. This can be done with both long (rifles and shotguns) and handguns. The marks on the bullets and the trajectory of the fired bullet's path, help investigators determine where a shooter was and what kind of firearm was used, thus, hopefully, narrowing down the list of suspects.
Firearms also leave distinctive marks,only they leave them on the bullets when they are fired. These marks help forensic investigators match bullets to the barrel of the gun that fired it. This can be done with both long (rifles and shotguns) and handguns. The marks on the bullets and the trajectory of the fired bullet's path, help investigators determine where a shooter was and what kind of firearm was used, thus, hopefully, narrowing down the list of suspects.