– It is important to note the prior activity of a subject. For example, if a subject had been at a shooting range earlier in the day you would expect to find GSR on them. Samples collected from the back of the hand should focus around the thumb and forefinger and the webbed area in between.

Where are GSR found?

Gunshot residue (GSR), also known as cartridge discharge residue (CDR), "gunfire residue" (GFR), or firearm discharge residue (FDR), is residue deposited on the hands and clothes of someone who discharges a firearm.

How is GSR tested?

Gun shot residue is tested by lifting samples off a defendant's hands or clothing and then testing to see if the lifts contain a fused particle of barium, antimony, and lead, which are known to be present in GSR. ... A positive GSR test result does not necessarily mean that a defendant has fired a gun.

What parts of a shooters hand are most likely to have high concentrations of GSR?

It was found that the back of the shooter's supporting hand contained over 30% more GSR particles than the shooter's firing hand. Results may differ for the shooters palm; however, this was not examined in this study.

What methods are used for the collection of organic GSR?

XRF and IMS are complementary methods that detect different components of GSR. XRF detects traditional, inorganic primer residues, while IMS detects organic compounds from stabilizers. XRF is non-destructive, so it does not interfere with subsequent analyses of any type.

Gunshot Residue Analysis for Law Enforcement - Sample Collection & Submission

What is GSR explain its collection methods?

INTRODUCTION: Gunshot residue results from the discharge of a firearm. This includes primer, powder, and/or projectile material and products of their combustion. ... Because various types of ammunition have different primer components, two collection techniques are utilized to enable effective analysis.

What chemicals make up GSR?

Although, all GSR contains the three primary inorganic components of lead, barium, and antimony, there are other metallic components that can be present as well. Most primer mixtures in bullets contain varying amounts of other types of metallic components, in addition to the original lead, barium, and antimony.

What is GSR distance determination?

To determine who may have shot the firearm, the Trace section performs gunshot residue (GSR) analysis. To figure out how far the shooter may have been from the victim, the Firearms section performs shooting distance determination.

How long is GSR detectable?

Per Wikipedia, GSR is the consistency of flour and typically only stays on the hands of a living person for 4–6 hours. Wiping the hands on anything, even putting them in and out of pockets can transfer GSR off the hands.

What two tests are performed to detect GSR on clothing?

Chemical test enhancement on GSR involves the use of Modified Griess test and Lunges reagent test to detect nitrites compound and Diphenylamine test to detect nitrates compound. As the distance of the muzzle to target cloth material increased, the intensity of the colour decreased and more widely distributed as well.

What type of evidence is GSR?

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. The concept is an old one and dates back many years.

What is GSR analysis?

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.

What is ballistic testing?

Ballistics testing is a standards-based process where products are tested to determine if they meet protection, safety and performance criteria. Most ballistics testing helps commercial research and development programs as well as law enforcement and military applications.

What are some ballistic databases?

The NIST Ballistics Toolmark Research Database (NBTRD) is an open-access research database of bullet and cartridge case toolmark data. The development of the database is sponsored by the U.S. Department of Justice's National Institute of Justice.

Where are extractor marks found on a cartridge case?

Extractor and ejector marks are produced when the cartridge case is mechanically extracted from the chamber and ejected and are visible as fine striations and gouged impressions on the rim and head of the case.

How is the amount of GSR affected by distance?

GSRs were detected in all shots. The mean size of the distribution area of barium and lead elements around the wound had a significant negative correlation with increasing shooting distance (r 0.97, p 0.001). As the distance increased, the amount of GSR de- creased, and this decrease rate was nonlinear.

Does peeing on your hands remove gunpowder?

Does peeing on your hands remove gunpowder? Yes, the urea in urine reacts with the saltpeter in gunpowder and renders it undetectable by the test commonly used for gun shot residue. ... Any gunshot residue is immediately cleansed.

How are guns test fired in a lab?

Most laboratories use a water recovery method, which is a large tank of water with a port into which the firearm is discharged. There are other systems used as well, such as metal boxes containing cotton waste material.

What is a distance determination?

Examiners test fire the firearm used in the crime and same or similar ammunition at a variety of muzzle to target distances. ... This allows the examiner to reproduce the pattern of nitrites and the presence of lead residues.

Why it is important to understand the GSR or gunshot distance determination?

GSR analysis can be of great value in helping determine who may have been involved in the shooting and approximate muzzle-to-target distances. ... Collection of gunshot residue from shooter's hand. A gunshot victim's clothing should be preserved as a GSR distribution pattern can assist in distance determinations.

What is the importance of distance determination?

Distance determination testing is important in cases where the distance a firearm was held from a target or victim becomes crucial in establishing what occurred during the commission of a crime or to establish self-defense (Osterburg & Ward, 2004).

What is GSR in criminal justice?

Page Content. When a firearm is shot, in addition to the projectile(s), a mass of debris comes out the muzzle. These gunshot residues (GSR) can include various primer residues, residues from projectiles, and partially burned and unburned gun powered particles.

What is the basis in administering the paraffin test?

A forensic test to indicate whether a person has recently fired a gun, in which the person's hand is coated in hot paraffin wax which cools and sets and is peeled off and tested for the presence of residue from the gun.

What are the parts of a bullet?

The basic components of ammunition are the case, primer, powder, and projectile(s). Shotshells have an additional component called wad.

How is gunshot residue transferred?

The results demonstrate the possibility of recovering considerable quantities of GSR from the hands of subjects as a result of a secondary transfer via a handshake with a shooter, or through handling a recently discharged firearm. As many as 129 particles were recovered from a handshake recipient.