Modern Trace Evidence Analysis and its Application to the Forensic Study of Soil, Sand and Dust

The basis for the forensic examination and analysis of microscopic trace evidence is stated in Locard’s Exchange Principle : Whenever two objects come into contact there is always a transfer of material between them While the amount of matter transferred may be small (and even undetectable by currently available methods) and the decay rate (i.e., loss of transferred matter over time) may be rapid, the exchange of matter during contact will nonetheless occur. The truth of this principle has been proven by research and casework, most of which was conducted during the last half of the twentieth century. It is one of the few scientific principles that forensic science can call its own since there is rarely a need to establish that two objects have come into contact in any other area of important scientific research.