Table of Contents
How is gunshot residue useful in forensics?
The examination and analysis of GSR on items of evidence can allow determinations to be made as to weather a hole or defect is consistent with being caused by a bullet (or other firearm-related projectiles).
How does an investigator identify a bullet casing?
Each spent casing should be marked using standard crime scene evidence identifiers such as “evidence tents,” placards, or similar devices. Typically, overall scene photos are taken first, followed by medium distance and close-ups.
What does gunshot residue determine?
Gun Shot Residue, or simply GSR, is a means of testing for the presence of certain materials on the hands and clothing of a subject in hopes of determining that this individual may have discharged a firearm.
What is the importance of gunshot residue examinations in the determination of the shooter or Gunner?
Gunshot residue (GSR) is a shred of important trace evidence which helps forensic scientists solve a huge range of incidents related to firearms. The identification of the shooter to bullet identification from a gunshot wound help reconstruct a scene of the crime.
How is GSR detected what forensic tests are involved?
Gunshot residue (GSR) analysis is a standard method to determine if a firearm has been used. Particles for GSR analysis typically range from 0.5 to 10 microns. Often the primer particles containing lead (Pb), barium (Ba) and antimony (Sb) are detected and analyzed using EDS in a scanning electron microscope.
Why would a forensic investigator want to analyze gunshot residue using and electron microscope?
Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) are well established techniques for the classification of gunshot residue (GSR) in forensic examinations. EDS analysis allows the identification of particles and classification of their characteristic chemical composition.
How is ballistic testing done?
Forensic ballistics involves the examination of evidence from firearms that may have been used in a crime. If investigators recover bullets from a crime scene, forensic examiners can test-fire a suspect’s gun, then compare the marks on the crime scene bullet to marks on the test-fired bullet.
What does a firearms examiner examine?
Summary of Duties: A Firearms Examiner examines and identifies firearms, weapons, cartridges, bullets, and similar evidence in criminal investigations; collects physical evidence at crime scenes; testifies in court concerning the results of examinations; provides expert testimony on general firearms capability and …
How is GSR tested in the crime laboratory?
A typical GSR collection kit contains adhesive disks to sample an individual’s hands. The adhesive disks are analyzed directly using scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX).
Why would a forensic investigator want to analyze gunshot residue using an electron microscope?
Scanning electron microscopes with energy dispersive x-ray spectroscopy allow the identification of very small amounts of GSR particles and the subsequent analysis of the surface morphology and composition of individual GSR particles with high accuracy.
How can GSR be used to determine shooter distance?
The size and density of the pattern of residues on the object can vary with distance, allowing a firearm examiner to determine the proximity of the shooter to the target when the gun was fired. Examiners visually examine and chemically process evidence for the presence of gunshot residues.
What is the importance of forensic analysis of firearm and gunshot residues in crime investigation?
The examination of individual and class characteristics of a spent bullet, spent cartridge or firing residues recovered from a crime scene can help classify the ammunition (make, calibre or gauge), trace the ammunition, establish the bullet trajectory, identify the shooting firearm, and establish links between the …