Gunshot forensic analysis

Of significance, however, is the long experience we have in the interpretation of the those results and in our understanding of the common misinterpretation of those results. An essential part of the interpretation of post-mortem drug analysis results is an understanding of post-mortem metabolism and redistribution 3, 4. It often very important to know exactly where on the body the sample was collected, as many drugs migrate in the decedent before the samples are collected. This is often critical in cases involving cocaine and opiates 1, 2.

Gunshot forensic analysis

Examination of Gunshot Residue Appearances of Gunpowder All gunpowders are designed to burn quickly to produce rapid expansion of gas in a confined space. In an explosion something gets very big very fast.

The burning rate of gunpowder can be classified in three categories: Unburned gunpowders can have recognizable shapes, colors, and sizes of grains. Pun and Gallusser, Composition of Gunshot Residue Firing a weapon produces combustion of both the primer and powder of the cartridge.

Considerations when examining gunshot residue:

The residue of the combustion products, called gunshot residue GSRcan consist of Gunshot forensic analysis burned and unburned primer or powder components, combined with additional residues from the surface of the bullet, surface of the cartridge case, and lubricants used on the firearm.

Residues can be either inorganic or organic in nature. Inorganic residues consist of elemental chemicals such as lead, barium, and antimony. Organic GSR primarily comes from materials derived from the propellant powder and are compounds classified either as explosives or additives based on their chemical composition.

Explosives can include nitroglycerine. Additives include stabilisers, plasticisers, deterrents, coolants, flash inhibitors and other components intended to improve the performance of the powder. Organic GSR can be detected on the hands up to several hours after discharge despite losses due to evaporation and skin permeation.

Taudte et al, These residues can be used to detect a fired cartridge. Gunshot residue may be found on the skin or clothing of the person who fired the gun, on an entrance wound of a victim, or on other target materials at the scene. The discharge of a firearm, particularly a revolver, can deposit residues even to persons at close proximity, so interpretations as to who fired the weapon should be made with caution.

Dalby et al, The major primer elements are lead Pbbarium Baor antimony Sb. When all three are present, the findings are characteristic for GSR; when one or two are present, the findings are consistent with GSR.

A mercury-fulminant based primer may be found in ammunition manufactured in Eastern Europe, while sinoxid type primers are used in the West. Blakey et al, Primer elements may be easier to detect in residues because they do not get as hot as the powder.

So-called "lead free" ammunition may contain one or more elements including strontium Srzinc Zntitanium Ticopper Cuantimony Sbaluminum Alor potassium K.

Both titanium and zinc are commonly used in paints and can be contaminants, but the appearance of particles containing them can be distinguished from gunshot residue by SEM.

Martiny et al, Dalby et al, The cartridge case, bullet, bullet coating, and metal jacket also contain specific elements that can be detected. A few have a nickel coating.

Gunshot forensic analysis

Primer cases are of similar composition Cu-Zn.Wound analysis allows a pathologist to determine the location, size, borders and pattern of the injury; the orientation on the skin’s surface; the thrust of the perpetrator; and whether the wounds are consistent with defensive actions.

Therefore, forensic gunshot acoustical analysis must include the overall sound level and the angular dependence for comparison to the recorded evidence.

Bayer School of Natural & Environmental Sciences

For this project, we designed, built, and implemented a test rig containing omnidirectional. Analysis of beveling in gunshot entrance wounds Analysis of beveling in gunshot entrance wounds Quatrehomme, Gérald; I̊şcan, plombier-nemours.comşar The analysis of skeletal trauma is an important aspect of forensic case work.

Yet most major pathology references devote limited attention to . Gunshot Residue It requires years of experience and examination of hundreds of cases to competently review and interpret the GSR findings in the full range of criminal cases involving guns.

All of the methods used should be accredited and stand up to scrutiny and full anti-contamination measures should be in . Malaysian Journal of Forensic Sciences 5(1) Analysis of Gunshot Residue Presence and Diameter of Bullet Hole on Different Surfaces.

Solehah Azman. Aug 21,  · Chemical Analysis of Firearms, Ammunition, and Gunshot Residue, Second Edition continues in the tradition of the popular first edition, filling the void in forensic texts on the subject.

While most books on firearms focus solely on the physical aspects of firearms, this book addresses forensic issues relating to the chemical aspects of firearms.

Gunshot Residue Expert Witnesses