Dalrymple
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Matthew Dalrymle posted Apr 30, 2024 8:07 PM
The presence of shell casings on the ground can add a lot more complexity to a crime scene. More so while trying to keep the scene uncontaminated by kicking the casings all over the place, as the location can play a crucial role in so much more. The casings will need to be taken to the forensic laboratory for processing. Before collection of the casing, ensuring they are not needed anymore, the photographs are done, and the sketch is completed. The casing has to be kept clean and non-contaminated by the individual collecting the evidence. When it gets back to the laboratory to be inspected the same carefulness has to be applied to taking it out. The first thing they will do normally is a visual examination. Looking for any distinctive markings or characteristics that could help identify the type of weapon fired. Then, the length, width, and caliber of the spent casing were used to identify the type of firearm that was used in the crime scene investigation. Knowing the caliber and the other pertinent information with the casing, they can determine the weapon used most of the time, as each one has its marks. They will compare the casing with other known ones to help ensure their decision was correct in the type of weapons used. As well as this will also allow them to see if some of the other casing used in previous crimes can be linked. The sizes will also tell if there were multiple weapons used. The most valuable marks on the cartridge cases are those made by the firing pin on the primer and by the breech face on the primer and base of the case, but the marks produced by the extractor ejector and the edge of the breech may also be important (Fisher, Pg 155). The forensic scientist may also analyze the spent casing under a microscope to check for individual characteristics left on the casing by the firearm, such as striations or tool marks. With the help of these unique qualities, it should be possible to determine which firearm was used in the commission of the crime. The properties of spent casings can be categorized as either individual or class traits. Individual features are exclusive to a particular firearm and can be utilized in order to identify the particular firearm that was used in the commission of the crime. Class characteristics are qualities that are typical of a specific class or kind of firearm and can be used to determine the general type of firearm that was used in an incident. Class characteristics can be used to determine whether or not a firearm was stolen.
The first task to be completed by a fire investigator upon arriving at the scene is the determination of the origin of the fire. The reason why the determination of the origin of the fire is important is that it has the greatest probability of having ILRs left from the fire accelerant usage. Logically, accelerants are the first material ignited since they tend to lower the ignition temperature compared to other materials. When they are found, the fire investigator must find out if they were used at the scene. This can be done by conducting a visual inspection of the scene, especially its origin. Among other factors to be looked at are pour patterns and intense localized burning. Two tools can be used at the crime scene to detect accelerants and explosives. These are; accelerant detecting canines and the use of portable hydrocarbon sniffers. Accelerant detecting canines are used for identifying if the accelerants were used at the scene and at the same time, they can be used in pinpointing the location where it was used. The canines are trained in detecting the trace levels of ILRs hence helping an investigator at the scene to a specific area with the highest likelihood of containing ILRs. Portable hydrocarbon sniffers are the current method being used by the investigators. They are handheld devices with the capability of sampling the vapors at the scene and can measure the number of hydrocarbons that they detect. When the concentrations of hydrocarbons have been detected, it is compared with the known values of ILR in areas that do not have any. The samples are then taken from areas with the highest concentrations.
Refences:
Guilmartin, J. F. (1998, July 20). P-51 Mustang | Facts, Specifications, & History. Encyclopedia Britannica. https://www.britannica.com/technology/P-51
U.S. Department of Defense. (n.d.). Strategic bombing matured quickly during WWII. https://www.defense.gov/News/Feature-Stories/story/Article/1995480/strategic-bombing-matured-quickly-during-wwii/
