Page 13 - The Smoking Gun Gunshot Residue
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as this chemical combination is unique to the includes noting the shape and appearance of the
compound. The explosion that forces a bullet out residue pattern, the Modified Griess Test, and the
of a gun chamber is one of the few ways that these Sodium Rhodizonate Test. The Modified Griess
three seperate elements can become fused into Test is the first chemical test performed because
a single element, therefore when these elements it will not affect later chemical tests. This test
are found in combination with each other, they are detects nitrite residues and is used to determine
classified as characteristic of gunshot residue. In muzzleto-garment distance. The clothing
the past, a particle containing only two of these specimen with the gunshot residue is placed
elements could be classified as gunshot residue, against a piece of desensitized photographic
however, since 2000, a particle containing all the paper, and the back of the specimen is steam
three elements is required to meet the scientific ironed with an acid solution in the iron instead
community’s threshold for establishing that a of water. Acidic vapors penetrate the specimen
substance is gunshot residue. causing a reaction between nitrite residues
and chemicals in the photographic paper. The
In crimes that involve firearm related deaths, Sodium Rhodizonate Test is used to determine
gunshot residue has proven to be a valuable tool if lead residues are present and is performed by
when examining the body of the victim. During spraying the specimen to be tested with sodium
an investigation of this type, examination of the rhodizonate and distilled water. Any lead residue
victim’s clothing includes a visual and microscopic present on the evidence will react with the sodium
examination of residue around the bullet hole that rhodizonate and turn a bright pink color.
THE MYSTERY OF LYLE AND LOUISE 13
