Identification, Collection and Preservation of Trace Evidences Research Paper

Identification, Collection and Preservation of Trace Evidences - Research Paper Example Most fiber piece contains similar physical nature with majority of such pieces found in crime scene are either made from polyester or nylon. The class characteristics includes weave pattern, dyes present, cordages, fabric impressions and tears (Brown, 2001). Thus, fiber in a crime scene is hard to identify without using microscopic and a combination of chemical and instrumental tests. Fibers are normally found in fabric abrasions with some trapped within torn material. In scenes involving hit-and-run motor vehicles fibers occur on scratched sections, and in burglary incidences they are normally found in tattered screens, clothing and broken glass (Brown, 2001). Collection is based on length of the fibers, such that if the fibers are undersized or few in numbers, the investigator is required to wrap the region or the entire product comprising the fibers in a paper (DuPre, 2013). However, if the fibers are large or in greater numbers, the investigator should place them in a bindle that is then placed in a sealed and marked coin envelope (Dutelle, 2011). The fibers should be picked up on tape if the lab in that jurisdiction permits it but with defined requirements. All clothing of belonging to an individual from which the fibers are found to have come from should also be picked for comparison purposes. Every garment should be placed on uncontaminated sheet of paper before separately rolling it up after marking the exhibit. Loose fibers should not be positioned directly into mailing wrapper since they can be lost (Buckles, 2010). Firearms Class characteristics found in firearms largely arises from the impact of bullets fired from the firearm, s uch as number and width of grooves, course of twist, or bullet diameter, in addition to the caliber and rifling patterns inside the barrel (DuPre, 2013). The cartridges and casings also have class characteristics like breech marks, impressions created by firing pin, in addition to extractor and ejector marks (Buckles, 2010). Firearms are easy to identify when there is transfer of the individual distinctiveness, chiefly striated marks left from the firearm to bullet and cartridge ammunition component (Brown, 2001). In terms of collection, the firearm should not be picked up through placing any other object in the barrel terminal. Unfired cartridges should not be left inside the magazine if the magazine is separated from the gun even as the rifles and shotguns must not be dismantled (Buckles, 2010). The investigator should not clean the firearm bore, chamber, or cylinder until they are submitted or even try to fire the firearm before it is evaluated in the Lab. Moreover, firearm havin g a cartridge inside the chamber must never be transported by any method since the firearm is not cocked or on-safety (Brown, 2001). The investigator should also record serial number, model, the firearm make, in addition to the weapon caliber (Hess & Orthmann, 2009). Marking should be done using an inconspicuous method that does not detract from its value, since copy serial numbers are sometimes on different firearms of a similar make and general-type. Nonetheless, model numbers and the firearm patent numbers should