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- All Subjects: Forensic Science
- Creators: Weidner, Lauren
The subcategory of evidence deemed trace evidence is frequently seen in crime scenes, and while it is commonly the smallest evidence around, that doesn’t stop it from greatly contributing to the findings at the scene. Blood evidence may be categorized into this group in certain cases at crime scenes, especially in cases of transfer between two objects or people. In this study, the transfer of blood across both porous and non-porous substrates was examined to determine the persistence of blood across both substrates. The resulting stains after each trial of transfers were tested with a presumptive blood test commonly used in crime labs, the Kastle-Meyer test. Throughout all trials of the experiment, it was determined that blood on a non-porous surface typically dries faster as long as there isn’t a pooling effect, which hinders the ability for a stain to be continuously transferred and detected by Kastle-Meyer. Conversely, porous substrates are more likely to absorb and retain the blood in the material, allowing the blood to be released when pressure is applied, causing the stain to transfer more easily and result in a stain that will produce a positive Kastle-Meyer result.
In this experiment, the viability of gunshot residue (GSR) was examined. This was done through the very rarely researched intersection of forensic firearms analysis and forensic entomology. The question being resolved is if GSR can reliably be detected from secondary evidence transfer of GSR laden carrion onto flies and their larvae. While it is know that secondary and tertiary GSR evidence can be transferred by way of handshakes, no such research has been conducted on flies or their pupae. Findings indicated varying levels of detection of GSR on evidence. GSR could reliably be detected on fly bodies and their legs, but not on their pupae. This research is significant as it provides previously unknown information on this line of research and provides the groundwork for further research on this topic in the future.
When it comes to murder, there are many ways to go about it. From blunt force trauma to gunshot wounds to strangulation. However, there is one way that can be very effective and can even look accidental. This is through poisoning, more specifically, using plants as a weapon. Now there are many plant poisoning cases throughout the state of Arizona, most being accidental and dealing with animals, but there is also malicious intent behind some. The plants Nerium oleander L. (Oleander), Cycas revoluta Thunb. (Sago Palm), Ricinus communis L. (Castor Bean), Datura stramonium L. (Jimsonweed), and Cicuta virosa L. (Water Hemlock) are known to be poisonous and they are utilized by both murderers and those that wish to attempt suicide. These are also killers of many animals whether that be livestock or the family dog who got into something they should not have. The toxin in these plants breaks down on its own and over time can become untraceable. Most of them will also cause death if not treated within a few hours of ingestion, making them the perfect weapon to use to get away with murder.