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.

Medicolegal forensic entomology is the study of insects to aid with legal investigations (Gemmellaro, 2017). Insect evidence can be used to provide information such as the post-mortem interval (PMI). Blow flies are especially useful as these insects are primary colonizers, quickly arriving at a corpse (Malainey & Anderson, 2020). The age of blow flies found at a scene is used to calculate the PMI. Blow fly age can be estimated using weather data as these insects are poikilothermic (Okpara, 2018). Morphological analysis also can be used to estimate age; however, it is more difficult with pupal samples as the pupae exterior does not change significantly as development progresses (Bala & Sharma, 2016). Gene regulation analysis can estimate the age of samples. MicroRNAs are short noncoding RNA that regulate gene expression (Cannell et al., 2008). Here, we aim to catalog miRNAs expressed during the development of three forensically relevant blow fly species preserved in several storage conditions. Results demonstrated that various miRNA sequences were differentially expressed across pupation. Expression of miR92b increased during mid pupation, aga-miR-92b expression increased during early pupation, and bantam, miR957, and dana-bantam-RA expression increased during late pupation. These results suggest that microRNA can be used to estimate the age of pupal samples as miRNA expression changes throughout pupation. Future work could develop a statistical model to accurately determine age using miRNA expression patterns.

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.

Forensic entomology is an important field of forensic science that utilizes insect evidence in criminal investigations. Blow flies (Diptera: Calliphoridae) are among the first colonizers of remains and are therefore frequently used in determining the minimum postmortem interval (mPMI). Blow fly development, however, is influenced by a variety of factors including temperature and feeding substrate type. Unfortunately, dietary fat content remains an understudied factor on the development process, which is problematic given the relatively high rates of obesity in the United States. To study the effects of fat content on blow fly development we investigated the survivorship, adult weight and development of Lucilia sericata (Meigen; Diptera: Calliphoridae) and Phormia regina (Meigen; Diptera: Calliphoridae) on ground beef with a 10%, 20%, or 27% fat content. As fat content increased, survivorship decreased across both species with P. regina being significantly impacted. While P. regina adults were generally larger than L. sericata across all fat levels, only L. sericata demonstrated a significant (P < 0.05) difference in weight by sex. Average total development times for P. regina are comparable to averages published in other literature. Average total development times for L. sericata, however, were nearly 50 hours higher. These findings provide insight on the effect of fat content on blow fly development, a factor that should be considered when estimating a mPMI. By understanding how fat levels affect the survivorship and development of the species studied here, we can begin improving the practice of insect evidence analysis in casework.

Arizona is number one in the nation for the most food waste sent to landfills according to a study by LawnStarter® (Ardoin, 2021). This unsustainable practice of food disposal has the potential to be mitigated with the use of black soldier flies (BSF) (Stratiomyidae: Hermetia illucens) as currently explored by Arizona Worm Farm (AWF). BSF larvae consume the food waste allowing a more sustainable method of disposal. In addition, these larvae can be a food source for livestock. In order to improve AWF’s current program, analysis of the facility, climate, food sources, organization, and pest identification was conducted. A series of tests were designed to determine the effectiveness of, and to make improvements to, existing feeding protocols and food sources. These included nutritional analysis of the larvae, feed conversion tests, and pH analysis and moisture content examination of the standard diet of spent brewer’s grain. Environmental parameters were improved through a new organizational system, a new light source for mating, new methods for controlling humidity, and sealed enclosures for pest prevention to increase efficiency and productivity of the program. The previous open water source for adults resulted in higher mortality rates than a new system which allows for the adults to receive moisture on a cloth and reduces the risk of drowning. This study led to the development of a comprehensive protocol that will improve and grow AWF’s program by reducing mortality of adults from pests, open water, and dry conditions. Other BSF programs will be able to use this for guidance in order to raise BSF on a large scale, as a food source and for waste reduction in their own communities.

As Arizona State University moves toward virtual classroom accessibility and the fortification of education for all students around the globe (ASU Online), we must continue to develop and cultivate creative resources to bring STEM laboratory activities to those who do not have access to the resources found in many classrooms. Online science degree programs face a particular challenge, as laboratory activities must be reformatted and rethought for virtual application. ASU has recently launched an online Forensic Science major, and the ability to identify and analyze evidence at a crime scene is one of the most important skills a student-investigator can learn. The development of creative ways to address instruction in a virtual crime scene is essential to the success of this and similar programs. Through the process of identifying evidence, students can hone their critical thinking skills, as they are required to assess scenarios and decide which evidence is pertinent to a given case. By making decisions regarding the packaging of identified evidence, students learn important steps in any forensic job, such as chain of custody, the effects of material packaging on evidence preservation, and the ramifications of incorrect evidence handling. Currently, there are several virtual crime scene programs available for purchase (Crime Scenes Meet Virtual Reality | St. Edward’s University in Austin, Texas). These programs offer activities such as those described above, yet they present a financial hurdle and are not customizable for specific courses or environments. Through the use of Google Slides, this project yielded an accessible and easily replicable interactive learning experience. The project resulted in a virtual crime scene that was both intuitive and integrative of generally novice technological resources such as Google Enterprise. Clickable photo slides were constructed using the linked shape imagery tools on Google Slides in order to provide an immersive learning experience.

The field of forensic science has been growing and changing with improvements in DNA analysis. One field affected is forensic entomology, which is exploring many ways in which DNA can increase the application of insects in forensic science. One application being explored is the use of insects as a source of human DNA in a criminal investigation. Using flies as a source of foreign DNA can also be utilized in ecological research to conduct surveys on the various species present in different environments. This experiment intends to determine if flies can act as a viable source of alternate DNA. This will be accomplished by an ecological survey of DNA extracted from flies. DNA extractions were performed on flies gathered from parts of the greater Phoenix area. The DNA was then amplified with primers targeting different animal species and examined to observe what animals the flies had come in contact with. Several samples had contamination due to human error and were not able to be evaluated. One DNA extraction out of fifteen yielded pig DNA, indicating flies can be used as a source of DNA. Future experiments should use different animal primers and amplify sections of DNA that can determine the different species consumed by flies. Further research into flies as a DNA source can increase the amount of information available to forensic scientists as well as improve ecologist’s observation of an environment’s biodiversity.

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.