Trace Evidence
The Study of Small Object Transfer
"Whenever two objects come into contact there is always a transfer of material. The methods of detection may not be sensitive enough to demonstrate this or the decay rate may be so rapid that all evidence of transfer has vanished after a given time. Nonetheless, the transfer has taken place."
-- Edmond Locard
Trace Evidence can be divided into two types of analyses.
Substance comparison- where the class characteristics of samples are compared to a known source to determine if the sample can be associated with a person or object. Examples of this type of comparison includes hairs, fibers, paint, soil, tape and glass.
Sample Identification- where samples are analyzed to try to determine if a particular substance is present. Examples of this type of analysis includes fire debris analysis, explosives, gunshot residue and substance identification.