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Bloodstain Pattern Analysis Essay

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Introduction

Bloodstain pattern analysis (BPA) is a subspecialty of forensic sciences, dealing with the analysis and interpretation of bloodstain patterns in crime scenes. The aim of BPA is uncovering new information about the actions that took place in a crime scene, potentially leading to a confirmation or refutation of a suspect's statement. A typical goal of BPA is to estimate the flight paths for a set of stains, followed by a directional analysis in order to estimate the area of origin for the stains. The traditional approach, referred to as stringing, consists of attaching a piece of string to each stain.
A correct distinction between bloodstain patterns formed by ‘‘contact transfer’and‘‘spatter’’ can be essential for the accurate …show more content…

Blood and the stain patterns created during these acts of violence are of particular interest to the forensic examiner. Bloodstains are routinely utilized to make critical forensic links between victim(s), suspect(s), physical evidence, and the crime scene. To assess the entire forensic value of a bloodstain, the stain must be located, and the physical characteristics of the individual stains that make up the overall pattern must be visualized in a nondestructive manner. Merely locating bloodstains on a garment is sufficient for DNA testing, but to fully understand the entire value of the stain patterns, there must be an ability to visualize the physical characteristics associated with the stain: stain size, shape, distribution, location, overall physical appearance, as well as the interrelationship between the bloodstain and the substrates on which they are located. A bloodstain pattern analyst will evaluate physical characteristics to determine what type(s) of mechanism(s) could account for a specific pattern. This pattern analysis can then be incorporated with other related forensic findings to reconstruct the events surrounding the blood-shedding …show more content…

A 50W Quartz Tungsten Halogen (QTH) white light source was used for sample illumination. We can use ChemImage Xpert software for the instrumentation during data collection. Because of the strongly absorbing nature of the denim fabric, a longer exposure time was required to achieve a suitable signal, as compared with the T-shirt sample. Because the bloodstain pattern on the denim sample could not be resolved using the NIR region of the spectrum, a short-wave infrared (SWIR) CONDOR Hyperspectral Imaging System (960-1650nm) was also used to collected NIR range would yield greater contrast. As with the NIR CONDOR, a QTH white light lamp was utilized for sample illumination. The experiment parameters for both NIR and SWIR data collection are listed in Table

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