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Bloodstain pattern analysis can provide telling evidence from a crime scene based on the clues left in the blood, but the field itself is highly problematic since the evidence extracted is dependent upon the interpretation of the analyst. Although some aspects of this type of analysis have been scientifically supported, most are not seen as positively accurate. Since certainty is the basis for acceptance of courtroom testimony, it is important that these unsettled aspects become more understood. This experiment examines the diameter of a weapon and how it affects its cast-off pattern. Weapons with four different diameters were used to generate 5 sample patterns under controlled conditions from each weapon diameter for a total of 20 patterns consisting of 3,367 droplets. The length and width of the pattern, the total number of droplets in the pattern, and the percentage of each droplet type (classified into low-velocity, medium-velocity, and high-velocity droplets) were recorded, averaged, and compared to each other individually using a t-test difference of two means assuming unequal variances. The results reveal that a higher percentage of droplets greater than 4 mm may indicate the use of a weapon with a wider diameter. The data also shows differences between the weapons that may be related to other factors besides the diameter of the weapon such as surface area or the curvature of the weapon. Still, more testing must be conducted to support these theories.
ContributorsBetz, Alexandra Marie (Author) / Kobojek, Kimberly (Thesis director) / Jacobson, David (Committee member) / School of Humanities, Arts, and Cultural Studies (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This study aimed to ascertain and measure the effect of news media on the public perception of crime scene investigation. Experimental subjects participated in a survey that collected relative demographic information, media habits, knowledge of crime scene investigation techniques, and relative accuracy of forensic science. The subjects were then exposed to excerpts of news media that diminished accuracy of DNA analysis and blood spatter analysis techniques, after which subjects answered questions about their opinions of crime scene investigation procedures after reading the materials presented. A total of 258 subjects were surveyed, after which data was compiled and analyzed using Chi-squared test as well as the McNemar test. Experimental data found that 52% of all respondents that participated in the survey had their opinions changed regarding the accuracy of crime scene investigation procedures following exposure to media. Further analysis of the data found that respondents in the 18-24 age demographic were significantly more likely to have their opinions changed following exposure to media as well as respondents with less education (defined as having earned less than an undergraduate degree). There was also significance found for the relationship between the amount of time spent per week watching CSI/Law Enforcement programs and opinions changed following exposure to media as well as the relationship between the amount of time spent per week viewing local news programs and opinions changed following exposure to media. Finally, there was significance found for the relationship between the time spent per week visiting social media sites and opinions changed following exposure to media.
ContributorsKemper, Jessica Danielle (Author) / Kobojek, Kimberly (Thesis director) / Jacobson, David (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05