Gunshot Residue and Tool-mark Evidence

Gunshot Residue

Gunshot residue is formed when a bullet exits the gun and it shoots burning gunpowder out of the barrel (Firearms ID). Particles and vapors are discharged from the gun when fired, causing gunshot residue (Lewis, 2004). The gunshot residue travels out the front of the gun and out the back of the gun, settling on the shooter's hand. At point blank the residue can travel all the way through the wound. (Firearms ID)

The distance between the clothing or object and the gun varies by the type of gun and ammunition that is used. Generally, gunshot residue will travel about three to five feet, but sometime can travel further. (Firearms ID)You can tell distance by the amount of gunshot residue on clothing. Gunshot residue is sometimes called "soot". (Lewis, 2004) In determining distance, gunshot residue has a limited distance. It can be determined when found near a wound because the gun must be close for the deposit. (Forensic institute.com)

A gunshot residue collection kit is used when collecting it. When collecting clothing, it must be packed separately. (Lewis, 2004) Hands can be analyzed using residue collection kits'. Then a Scanning Electron Microscope (SEM) and an Energy Dispersive Analysis with X-Ray (EDX) is used to see the components better. (Forensic institute.com) NIBIN (National Integrated Ballistics Information Network) is a computer network similar to the one used for fingerprint identification, IBIS.

Gunshot residue is very important when processing a crime scene because it gives you an approximate distance since the soot will only travel so far. It is also important because if found at the scene, and on the suspects hands, you can make a match. A match can also be made by analyzing the sleeves of the shooter. (Forensic institute.com)

Tool-marks