For crimes that involve the use of a firearm, gunshot residue (GSR, for short), can play a major role in determining who committed the crime.
What is Gunshot Residue?
When a gun is fired, hundreds of nearly invisible particles are blown backwards toward the shooter. The particles consist of lead, barium and antimony. The combination of these particles is gunshot residue. When the particles are expelled backwards, they stick to the shooter’s hands.
Where is GSR typically found?
In the case of a shooter, GSR is usually found on the thumb and index finger, including the “webbing” that connects the thumb and index finger. GSR is sometimes also found as far back as the wrist and lower arm.
How do the Police find Gunshot Residue?
To collect gunshot residue, police use a small, round tube-like device. The tube is approximately one and-a-half inches long. One side of the tube is a plastic piece, which has a metal “mount” on the inside. The mount has an adhesive covering. This side is referred to as the stub. The other side of the tube is simply a clear plastic covering. This side is called the holder.
When police want to collect gunshot residue, they will have the person hold out each hand. They will take the collection device and remove the holder from the stub. Then, police will take the stub and touch the mount over the areas of the hand they wish to test. If there is GSR on the hands, it will stick to the adhesive on the mount. Once this is completed, the stub is placed back in the holder and is sent for GSR testing.
How long does GSR stay on the hands?
Not very long. Studies have shown that a hard slinging or shaking of the hand will scatter some of the particles. If the hand is rubbed against clothing or wiped with a towel, there’s a good chance that most, if not all, gunshot residue will come off the hands. If the hands are washed, GSR is most likely gone.
It’s also possible for the police to inadvertently remove gunshot residue from a suspect’s hands during handcuffing. When an officer handcuffs a suspect, the GSR can be transferred from the suspect’s hands to the handcuffs, and even to the officer’s own hands.
The more time that is placed between the GSR being deposited on the hands and the time the test is performed, the more chance there is for the residue to disappear.
What does the presence of gunshot residue prove?
Viewed by itself, the presence of gunshot residue simply proves that a person’s hand has come into contact with gunshot residue. Period.
But, when the presence of GSR is viewed along with other evidence against a suspect, it can make a fairly tight case that the person committed the crime.
What does the presence of GSR not prove?
The presence of GSR does not conclusively prove that a person fired a gun. This is because the mere presence of GSR does not prove how the GSR got on the hands in the first place.
It’s true that gunshot residue is most likely deposited when a person fires or handles a recently fired firearm. However, there is at least a likelihood that GSR can be transferred by touching another person who has GSR on his hands, or by touching a surface (such as a body) that has residue on it (close-range gunshot wounds have residue deposits around the entry wound). These are less probable explanations, but must be kept in mind before thinking GSR is the literal “smoking gun” in a crime.
Forensic evidence is a part of every violent crime. I’m fortunate to have been law enforcement trained in forensic evidence, including the collection of gunshot residue. If you’ve been charged with a violent crime, you need a tough Mississippi criminal defense attorney with a thorough knowledge of forensics. Please contact me to discuss your case.