Brendan Chapman

Analysis of illicit drug samples traditionally focuses on chemical impurity profiling for identifying drug origin and linking seizures. This method relies on detecting impurities such as bulking agents (e.g. starch), enhancing agents (e.g. procaine hydrochloride), manufacturing precursors (e.g. pseudoephedrine in methamphetamine) and synthesis by-products. However, a trend towards a final product of greater purity has reduced available chemical impurity data, thereby limiting definitive profiling.

An emerging research area explores extracting trace human DNA and environmental DNA (eDNA) from capsule surfaces and illicit drug powders. It may be expected, however, that perpetrators may take greater care to avoid leaving fingerprints or human DNA on drug packaging, highlighting the need for alternative forensic methods. In such circumstances, eDNA presents a promising avenue, identifying bacterial, fungal, plant, and eukaryotic cells from diverse sources like soil, air, and water that may provide clues as to the location of manufacture as well as potential trafficking routes. The research highlights the importance of integrating eDNA analysis with conventional chemical methods in forensic illicit drug investigations.

Purpose
Approximately 20% of road fatalities can be attributed to driver fatigue; however, there are relatively few options available for police to specifically address this danger. Salivary biomarkers are a promising solution as saliva collection is non-invasive, quick, and easy to perform in roadside settings. Metabolomics is emerging as a useful tool for biomarker detection because it allows for the comprehensive profiling of small molecules, providing insights into subtle biochemical changes that may be 8associated with fatigue. This pilot study aims to explore the potential of metabolomic approaches in discovering fatigue biomarkers in saliva.

Methods
Saliva samples were collected from participants (n = 12) at baseline (well-rested) and following sleep deprivation. Participants also provided subjective ratings of perceived fatigue and cognitive inhibition was assessed via the three-minute psychomotor vigilance task (PVT). Saliva samples were analysed using proton nuclear magnetic resonance (1H NMR) spectroscopy. 1H NMR data was interrogated using multivariate (O-PLS) and univariate (Kruskal-Wallis, Spearman’s Correlation) analyses to identify metabolites associated with fatigue.

Results
O-PLS identified seven metabolites as potential biomarkers of fatigue, but only scyllo-inositol reached statistical significance when interrogated univariately. No significant correlation was observed between PVT scores and self-reported fatigue, raising questions about the validity of specifically the three-minute PVT, compared to either the five or ten-minute variety, as a measure of cognitive inhibition.

Conclusion
This pilot study highlights scyllo-inositol as a potential salivary biomarker for fatigue, but further validation in larger cohorts is necessary. Additionally, recommendations are made for improving similar research.

In forensic science, detecting transfers of physical and biological material is critical for establishing evidence of criminal involvement. Unique bacterial signatures from the reproductive system transfer during unprotected penetrative intercourse offer a novel tool for criminal investigation. Here, we demonstrate this transfer using full-length 16S rRNA gene sequencing and discuss the impact of barrier contraceptives. These microbial signatures can potentially aid in sexual assault casework for perpetrator identification when human male DNA is absent.
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•Transfer of unique and non-unique bacterial taxa during intercourse was observed•Lactobacillus spp. contributed to the most female to male sexome transfer•Despite the use of a condom during intercourse, transfer of the sexome was still observed•Condom/lube use, oral intercourse, circumcision/pubic hair: no impact on microbial diversity
Biological sciences; Microbiome

Extended reality (XR) devices, including virtual and augmented reality head-mounted displays (HMDs), are increasingly utilised within healthcare to provide clinical interventions and education. Currently, XR devices are utilised to assist in reducing pain and improving psychological outcomes for immunocompromised patients in intensive care units, palliative care environments and surgical theatres. However, there is a paucity of research on the risks of infection from such devices in healthcare settings. Identify existing literature providing insights into the infection control risk XR HMDs pose within healthcare facilities and the efficacy of current infection control and cleaning procedures. Three databases (PubMed, Embase and CINAHL) in addition to Google Scholar were systematically searched. A total of seven studies were identified for this review. Microorganisms, including pathogenic bacteria (e.g., Staphylococcus aureus and Pseudomonas aeruginosa), were found to be present on XR HMDs. Published cleaning and infection control protocols designed to disinfect XR HMDs and protect users were heterogeneous in nature. Current cleaning protocols displayed varying levels of efficacy with microbial load affected by multiple factors, including time in use, number of users and XR HMD design features. In healthcare settings, fitting XR HMDs harbouring microorganisms near biological and mucosal entry points presents an infection control risk. An urgent revision of the Spaulding classification is required to ensure flexibility that allows for these devices to be reclassified from ‘Non-critical’ to ‘Semi-Critical’ depending on the healthcare setting and patient population (surgery, immunocompromised, burns, etc.). This review identified evidence supporting the presence of microorganisms on XR HMDs. Due to the potential for HMDs to contact mucosal entry points, devices must be re-considered within the Spaulding classification as ‘Semi-critical’. The existence of microbial contaminated XR HMDs in high-risk medical settings such as operating wards, intensive care units, emergency departments, labour and delivery wards and clinical areas with immunosuppressed patients requires urgent attention. Public health authorities have a duty of care to develop revised guidelines or new recommendations to ensure efficient sanitation of such devices.

Deceased human remains are often buried as a forensic countermeasure or method of disposal by homicide perpetrators. Owing to this, the excavation of clandestine grave sites is a task that forensic crime scene teams may only encounter a few times a year. Not all crime scene units have specialised teams for this task, and even those that do, may not have specific protocols for the optimal recovery of forensic traces retained within grave fill as procedures such as sieving require optimisation for the specific soil conditions of the jurisdiction. This study aimed to define the optimal sieving conditions for a sandy environment when searching for minute traces of paint, glass, hair and fibres. Furthermore, this study justifies the practice of retaining grave fill and examining it under controlled laboratory conditions, rather than in-situ adjacent to the grave site. The results demonstrate that using sieve mesh sizes as fine as 0.1 mm can recover up to 82% of the deposited traces and almost all paint, hair and glass traces. The processing of grave fill in the laboratory lead to increased yield of forensic evidence, which on a case-basis may warrant the increased time needed. These findings merit consideration for clandestine grave crime scenes where evidence is scarce or the case is likely to become cold.

Cold case reviews within police and law enforcement agencies are challenging, not the least owing to the amount of time required to carefully review documentation, forensic exhibit holdings and various other casefile information. Most federal and state agencies are time poor, meaning there are very few dedicated cold case teams fortunate enough to have an abundance of police and expert staff resources. Universities and education organisations, however, have large troves of various expertise, alongside expansive human resources, by way of their academic and student body. In certain circumstances, the academic expertise and course offerings of a university may be well suited to assisting law enforcement in reviewing cold cases.

There is growing desire for university courses to generate job ready graduates. In the field of law enforcement and policing this is difficult, as safety and the security of sensitive material and evidence is paramount. Educators strive to create workplace simulations, and with the correct mix of academic expertise, course offerings and industry linkages, the emerging opportunity for real cold case collaboration is possible. One such example is the Cold Case Review @ Murdoch (CCR) initiative. Since 2020, CCR has worked with the Lower Saxony Police Academy in Germany to develop the novel International Cold Case Analysis Project (ICCAP), now incorporating over 25 member institutions, to assist in solving real cases from both Niedersachsen (Lower Saxony) and federal police jurisdictions. One case, known as “The North Sea Man” has shown great success and demonstrates the power of joining forces between law enforcement and external agencies to help advance cold cases.

Forensic samples for DNA analysis are limited by physical size and volume as DNA extraction methods require small portions placed into 1.5 or 2.0 mL tubes for lysis. Apart from tape lifting techniques, this precludes large sample areas from being harvested of cellular material by any means other than washing or wet vacuuming. In addition, forensically savvy perpetrators may employ clean-up methods to remove DNA evidence by way of wash basins and sinks, although evidence may be retained within the p-trap of plumbing. Both outcomes still leave forensic biologists with samples incompatible with most commercial DNA extraction methods. Fields of microbiology and ecology have long used environmental DNA (eDNA) collection methods to overcome the similar challenges of sampling biota within large volumes of water or liquid samples. This study is the first application of eDNA techniques to capture such dilute traces of human cellular material from large water volumes using a microfiltration method. The technique was able to isolate human DNA from as little as 100 cells in 1 L of water. While future optimization is required to determine ideal filter specifications, this research demonstrates a proof of concept for forensic application in cases with challenging substrates that can be washed or contain water. This research was conducted under the Murdoch University Human Research Ethics Committee approval 2019/025.

Sexual assault can be one of the most personally violating and horrific acts enacted on an individual, second only to murder. Forensic science has constantly evolved to become more equipped to respond to these offenses- yet there are still opportunities for advancement. This article describes the forensic processes from the outset of a sexual assault investigation, focussing on the primary target of forensic biology analyses- offender cellular material, namely semen and spermatozoa evidence. Understanding the biology and characteristics of this complex body fluid aids forensic biologists in targeting it to identify a perpetrator.

Violence in serial homicide is a complex and dynamic part of an offender’s behavior. This chapter explores how aggressive and violent behavior is a part of serial homicide and the escalation of aggression to violence. The organized/disorganized dichotomy of serial killers and reactive and proactive aggression is used to help explain different types of aggression and how they may be exhibited during the commission of a crime. The proposed aggression–violence continuum conceptualizes aggression on a behavior continuum for offending behaviors and helps to visualize how violent an offender may be. The violence portion of the continuum is then further broken down into the tiers of serial violence that demonstrate an ascending level of violence and presents the escalating nature of serial homicide.

The detection and recovery of male DNA post-assault is important in sexual assault investigations, particularly where an offender is unknown to the victim. The collection of DNA evidence often occurs when the female victim undergoes a forensic medical assessment. Analysis regularly results in mixed autosomal DNA profiles with both victim and perpetrator DNA, often making it difficult to interpret a male profile suitable for DNA database searching. While short tandem repeat (STR) profiling of the male Y-chromosome is often used to overcome this challenge, successful identification of an individual can be hindered by the paternal inheritance pattern of Y-STRs and small Y-STR databases. Human microbiome research has suggested that a person’s microbial diversity is unique. Therefore microbiome analysis using Massively Parallel Sequencing (MPS) could serve as a useful adjunct method of perpetrator identification. This study aimed to identify bacteria taxa that were unique to each participant and compare the bacterial communities found on their genitals both pre- and post-coitus. Samples were collected from six male-female sexual partner pairs. Volunteers were asked to self-collect low vaginal (females) and penis shaft and glans (males) samples before and after intercourse. Samples were extracted using the PureLink™ Microbiome DNA Purification Kit. Extracted DNA underwent library preparation using primers targeting the V3-V4 hypervariable regions of the bacterial 16S rRNA gene (∼450 bp). Libraries were sequenced on the Illumina MiSeq® platform. From the sequence data derived, statistical analysis was performed to investigate if bacteria sequences could be used to infer contact between each male-female pairing. Unique bacterial signatures were detected in low frequencies (<1%) in male and female participants pre-coitus. The data indicated a significant disruption to microbial diversity post-coitus in all samples. A transfer of the female microbiome during intercourse was most significant. As expected, one couple who did not use a barrier contraceptive yielded the most microbial transfer and disruption to diversity demonstrating a proof-of-concept in the utility of microbiome interrogation for sexual assault cases. Further genomic analysis is needed to confirm species and subspecies classification of bacteria that may produce a unique microbial profile that could then be used to identify a specific individual.