Investigating The Theories Of Trace Evidence

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Trace evidence can be used to link people or objects to places, other people, or other objects. This often serves as a starting point, or lead, for a particular line of investigation (Lothridge, 2016). Trace evidence can include a wide variety of materials, but most commonly tested are hair, fibers, paint and glass. Other, less frequently included items are soil, cosmetics and fire debris (Lothridge, 2016). Dr. Edmond Locard formulated the theory that "Every contact leaves a trace". This became known as Locard 's exchange principle (Lothridge, 2016). Tools such as tweezers, tape, specialized vacuums, swabs, alternate light sources, and lasers to find and collect trace evidence. Fibers and Threads can be found on burglaries and hit and…show more content…
If the fibers are short or few in number, and if it is possible to do so, wrap the area or the entire item containing the fibers in paper and send the whole exhibit to the Laboratory. When fibers or threads are recovered, always send all clothing of persons from which they might have originated to the Laboratory for comparison purposes. When a window is damaged in a burglary, or the headlights of a hit and run case all glass should be recovered. Shoes and clothing of a suspect or other objects contaminated with glass should be wrapped in paper and submitted to the laboratory for examination. Glass from different locations should be kept in different containers. All glass should be collected because there could be more than one type present. Small glass fragments should be placed in paper bindles, then in coin envelopes, pill boxes, or film cans which can be marked and completely sealed. Large glass fragments can be placed in boxes. Individual pieces can be separated with cotton or tissue to prevent breakage and damaged edges during shipment. As part of the investigation of vehicle accidents, it may be of importance to determine whether or not a headlight or taillight was illuminated at the time the light was broken. Recovery of the filaments is of primary importance. If recovered, it should be placed in a paper bindle or a small pill box sealed with tape. Whether or not the large filaments are located, all remaining
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