Page 9 - The Smoking Gun Gunshot Residue
P. 9
Pre-Lab
Solutions
1. Where are GSR samples obtained from when 7. Where do lead residues originate?
taken from the hands? Lead residues originate from the primer used to
Samples should be taken from the front and ignite the cartridge.
back of the index finger, thumb, and the web
space in between.
8. What test is the first chemical test performed
to determine if GSR is present?
2. Where is GSR preserved the longest? The Modified Griess Test is the first
GSR is preserved the longest on clothing. chemical test performed to determine if
GSR is present.
3. How long can GSR residue remain at a crime
scene? 9. What test determines the presence of lead?
GSR can remain indefinitely at a crime scene The Sodium Rhodizonate Test determines the
presence of lead.
4. What are the components of GSR?
GSR residue is composed of explosive primer, 10. What is the difference between GSR patterns
propellant, and parts of the bullet, cartridge of close range and more distant ranged
case, and the firearm. shots?
The closer the shot, the more concentrated and
tighter the configuration of GSR.
5. What shape does the plume of GSR take as it
exits the firearm?
The plume takes the shape of a cone pattern as 11. What elements are detected when using SEM
it exits the firearm. to detect GSR?
SEM is used to detect the elements of lead,
barium, and antimony.
6. What makes up black powder?
Black powder is made up of potassium nitrate,
charcoal, and sulfur.
THE MYSTERY OF LYLE AND LOUISE 9
