Joining forces: Combining police and external expertise for cold case reviews.

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.

Extended Reality Head-Mounted Displays Are Likely to Pose a Significant Risk in Medical Settings While Current Classification Remains as Non-Critical.

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.

A controlled method for the identification of forensic traces from clandestine grave fill.

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.

The Sexome - A proof of concept study into microbial transfer between heterosexual couples after sexual intercourse.

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.

Finding the missing and unknown: Novel educational approaches to warming up cold cases.

In recent years, students in police academies and higher education institutions around the world have worked together to analyse cold cases including long-term missing persons cases in collaboration with investigators and prosecutors. In 2020, three European organisations, the Police Expert Network on Missing Persons (PEN-MP), AMBER Alert Europe and Locate International, succeeded in connecting these educational organisations enabling them to work collectively on cases and conduct cold case analyses (CCA) across international borders. The International Cold Case Analysis Project (ICCAP) learning objectives were to 1) collect the necessary information about the victim, 2) reconstruct the crime, and 3) investigate trace control. In a learning objective-based evaluation using Computer-Assisted Web Interviewing, 76 participating students from the German and International ICCAP teams were asked to complete a pre- and post-review questionnaire to self-assess their personal competence development. Participants reported significant increases in competence in all evaluated areas, thus demonstrating that authentic and relevant collaborations can enrich the learning environment, promote the use of professional skills, and provide significant knowledge exchange opportunities between academia and industry. Drawing on case studies of cold case missing persons' investigations and unidentified found remains, this article shares how university academics, students and community volunteers can work together nationally and internationally to find out what has happened to missing people and how we can more effectively identify the previously unidentified. In so doing, we share the expertise required to progress these cold cases and provide recommendations to support other institutions and organisations in adopting this innovative approach.

Methods for ensuring the highest DNA concentration and yield in future and retrospective trace DNA extracts.

In forensic laboratories, increased extraction efficiency of trace evidence is paramount because analytical success is intrinsically dependent on the quantity of DNA recovered. Moreover, highly concentrated nucleic acids are vital for effective downstream analysis and high quality results. This study investigated the efficiency of extraction with the Qiagen® QIAamp® DNA Investigator kit, and explored improvements to the methodology that would maximise the recovery of low concentration forensic samples. Controlled amounts of starting cellular material were used to mimic trace (or low level) DNA deposits prior to DNA extraction with the Investigator kit. Addition of the provided carrier RNA along with conducting two successive elutions of 50 µL improved the net recovery of DNA to 95%. Concentration with centrifugal filters post-extraction were able to concentrate DNA but a large net loss was observed. For the concentration of historic, retrospectively extracted DNA, centrifugal methods are able to concentrate DNA extracts previously too dilute for analysis. These concentrated volumes, however are small, allowing for minimal downstream analysis attempts before the sample is exhausted.

Virtual anthropology? Reliability of three-dimensional photogrammetry as a forensic anthropology measurement and documentation technique.

Osseous remains provide forensic anthropologists with morphological and osteometric information that can be used in building a biological profile. By conducting a visual and physical examination, an anthropologist can infer information such as the sex and age of the deceased. Traditionally, morphological and osteometric information is gathered by physically handling remains for analysis. With the advancement of digital technology, there has been a shift from direct to indirect methods of analysis by utilizing models generated from three-dimensional (3D) imaging, which includes computed tomography (CT) scanning and 3D photogrammetry. Although CT scanning is more common, photogrammetry has found application in a range of fields such as architecture, geography and road accident reconstruction. The application of modern-day photogrammetry for forensic anthropology purposes, however, has not been discussed extensively. The aim of this research was to validate the accuracy of 3D models generated by photogrammetry by comparing them to both 3D models generated by CT scanning and the actual physical models. In this study, six 3D models were created using photogrammetry (n = 3) and CT scanning (n = 3). The 3D models were generated from three different Bone Clone® human skulls. A mobile phone camera was used to capture images, which were then processed in Agisoft Metashape®. Intrarater, interrater, and intermethod reliability tests gave correlation coefficients of at least 0.9980, 0.9871, and 0.9862, respectively; rTEM results ranged from 0.250 to 6.55%; and an analysis of variance (ANOVA) yielded P values under 0.05 for all measurements except one. Statistical tests therefore showed photogrammetry to be a reliable and accurate alternative to more expensive CT scanning approaches.

The novel use of a spray-on rubber coating to recover cellular material from the surface of bricks.

Currently, forensic investigators utilise various types of swabs and tape lifts to recover cellular material from coarse surfaces identified during a criminal investigation. However, a number of challenges prevent successful recovery and therefore warrants the need for an alternative method. Plasti dip® is peel-off rubber coating that can be applied to most surfaces and may have an application in the recovery of DNA from coarse surfaces. The aim of this study was to determine the effectiveness of Plasti dip® to recover DNA from coarse brick surfaces and assess how this method compares to current techniques. Cellular material was deposited onto brick pieces in varying concentrations and recovered with either flocked, foam or rayon swabs, or Plasti dip®. Material recovered, using each technique, was extracted and quantitated for comparison of DNA yields. At low and medium cell concentrations, an observable but not statistically significant difference was observed between the swabbing methods and Plasti dip®. At high cell concentrations Plasti dip® was able to recover a significantly higher DNA concentration than all three swabbing methods. Quantitation results indicated no degradation of DNA. This is a novel approach to the collection of trace DNA from surfaces that have historically proven difficult to sample. While there is further validation required, this landmark study demonstrates the potential that spray-on rubber coatings have for casework involving rough, porous surfaces like bricks, stones or rocks.

Working the crowd for forensic research: A review of contributor motivation and recruitment strategies used in crowdsourcing and crowdfunding for scientific research.

Crowdsourcing and crowdfunding have been successfully used in a range of scientific disciplines and present opportunities for forensic researchers to draw on the power of large numbers of people to contribute to research projects through participation or by providing an alternative source of funding. This review aimed to examine whether contributors to crowd science and crowdfunding for scientific research are motivated to participate or provide financial support by the same factors, and to examine recruitment strategies in an attempt to identify a potential crowd for forensic researchers to approach. There was found to be limited research into crowdfunding for scientific research that addressed the motivations of contributors or recruitment strategies used, and no conclusions could be made. There is a need to overcome low response rates and high attrition over the lifetime of a crowd science project or crowdfunding appeal. It is necessary to target a large number of people who are interested in the subject studied and who want to make a difference in some way and contribute to science. True crime podcast audiences are proposed as they present large numbers of listeners who are interested in forensic science, criminal investigation or law enforcement. These audiences have been targeted for successful fundraising efforts and invitations to participate in crowd activities previously. They should be considered by forensic researchers who are looking to venture into crowdsourcing or crowdfunding for research projects.

Examination of the temporal variation of peptide content in decomposition fluid under controlled conditions using pigs as human substitutes.

We report the preliminary observations of the peptide content of decomposition fluid produced under controlled laboratory conditions and in the absence of a soil matrix. Four domestic pig (Sus scrofa domesticus) cadavers were used to model human decomposition over a four-week trial period; physical characteristics were recorded and the peptide components of decomposition fluid was analysed using high performance liquid chromatography-time of flight mass spectrometry. Preliminary data analysis indicated that a range of peptides were consistently detected across the course of the trial period and 27 of these were common to all four cadavers; 22 originating from haemoglobin. The peptides associated with haemoglobin subunit alpha and beta displayed a breakdown pattern that remained consistent for all cadavers for the duration of the trial. Though identification of peptides during decomposition has potential for estimating the time since death, quantification of selected peptides is likely to be essential to identify time-dependent trends.

A pilot study: The effects of repeat washing and fabric type on the detection of seminal fluid and spermatozoa.

In sexual assault cases and more specifically those involving childhood sexual abuse (CSA), victims may have had their potentially semen-stained clothing washed multiple times before a criminal investigation commences. Although it has been previously demonstrated that spermatozoa persist on cotton clothing following a single wash cycle, items of clothing washed multiple times are not routinely examined in these cases because of the assumption that the laundering process would have removed all seminal fluid and spermatozoa. The aim of this study was to examine the persistence of seminal fluid and spermatozoa on a range of fabric types including cotton, nylon, terry towel (100% cotton), polyester fleece, satin and lace which were laundered up to six times. Three techniques were used for the detection of seminal fluid and spermatozoa: an alternative light source, acid phosphatase test and microscopy. The study demonstrated that spermatozoa persisted on cotton and terry towel following six wash cycles. This data emphasises the need to recover and examine items of clothing and bedding of victims for semen, even if the item has been washed multiple times.

Short-duration stimulation of the supplementary eye fields perturbs anti-saccade performance while potentiating contralateral head orienting.

Many forms of brain stimulation utilize the notion of state dependency, whereby greater influences are observed when a given area is more engaged at the time of stimulation. Here, by delivering intracortical microstimulation (ICMS) to the supplementary eye fields (SEF) of monkeys performing interleaved pro- and anti-saccades, we show a surprising diversity of state-dependent effects of ICMS-SEF. Short-duration ICMS-SEF passed around cue presentation selectively disrupted anti-saccades by increasing reaction times and error rates bilaterally, and also recruited neck muscles, favoring contralateral head turning to a greater degree on anti-saccade trials. These results are consistent with the functional relevance of the SEF for anti-saccades. The multiplicity of stimulation-evoked effects, with ICMS-SEF simultaneously disrupting anti-saccade performance and facilitating contralateral head orienting, probably reflects both the diversity of cortical and subcortical targets of SEF projections, and the response of this oculomotor network to stimulation. We speculate that the bilateral disruption of anti-saccades arises via feedback loops that may include the thalamus, whereas neck muscle recruitment arises via feedforward polysynaptic pathways to the motor periphery. Consideration of both sets of results reveals a more complete picture of the highly complex and multiphasic response to ICMS-SEF that can play out differently in different effector systems.

Recruitment of a contralateral head turning synergy by stimulation of monkey supplementary eye fields.

The supplementary eye fields (SEF) are thought to enable higher-level aspects of oculomotor control. The goal of the present experiment was to learn more about the SEF's role in orienting, specifically by examining neck muscle recruitment evoked by stimulation of the SEF. Neck muscle activity was recorded from multiple muscles in two monkeys during SEF stimulation (100 µA, 150-300 ms, 300 Hz, with the head restrained or unrestrained) delivered 200 ms into a gap period, before a visually guided saccade initiated from a central position (doing so avoids confounds between initial position and prestimulation neck muscle activity). SEF stimulation occasionally evoked overt gaze shifts and/or head movements but almost always evoked a response that invariably consisted of a contralateral head turning synergy by increasing activity on contralateral turning muscles and decreasing activity on ipsilateral turning muscles (when background activity was present). Neck muscle responses began well in advance of evoked gaze shifts (~30 ms after stimulation onset, leading gaze shifts by ~40-70 ms on average), started earlier and attained a larger magnitude when accompanied by progressively larger gaze shifts, and persisted on trials without overt gaze shifts. The patterns of evoked neck muscle responses resembled those evoked by frontal eye field (FEF) stimulation, except that response latencies from the SEF were ~10 ms longer. This basic description of the cephalomotor command evoked by SEF stimulation suggests that this structure, while further removed from the motor periphery than the FEF, accesses premotor orienting circuits in the brain stem and spinal cord in a similar manner.

Neuromuscular recruitment related to stimulus presentation and task instruction during the anti-saccade task.

The contextual control of movement requires the transformation of sensory information into appropriate actions, guided by task-appropriate rules. Previous conceptualizations of the sensorimotor transformations underlying anti-saccades (look away from a stimulus) have suggested that stimulus location is first registered and subsequently transformed into its mirror location before being relayed to the motor periphery. Here, by recording neck muscle activity in monkeys performing anti-saccades, we demonstrate that stimulus presentation induces a transient recruitment of the neck muscle synergy used to turn the head in the wrong direction, even though subjects subsequently looked away from the stimulus correctly. Such stimulus-driven aspects of recruitment developed essentially at reflexive latencies (∼60-70 ms after stimulus presentation), and persisted at modest eccentricities regardless of head-restraint. Prior to stimulus presentation, neck muscle activity also reflected whether the animals were preparing for an anti-saccade or a pro-saccade (look toward a stimulus). Neck muscle activity prior to erroneous anti-saccades also resembled that observed prior to pro-saccades. These results emphasize a parallel nature to the sensorimotor transformations underlying the anti-saccade task, suggesting that the top-down and bottom-up processes engaged in this task influence the motor periphery. The bottom-up aspects of neck muscle recruitment also fit within the context of recent results from the limb-movement literature, showing that stimulus-driven activation of muscle synergies may be a generalizing strategy in inertial-laden systems.

Properties of human eye-head gaze shifts in an anti-gaze shift task.

We investigated the metrics and kinematics of human eye-head gaze shifts using the anti-gaze shift task. Surprisingly, no systematic difference was found between peak gaze velocities of large pro- and anti-gaze shifts. In a follow-up experiment that equated perceived stimulus luminance across multiple eccentricities, pro-gaze shifts were consistently faster than anti-gaze shifts. In both experiments, we did not observe any head-only errors where initial head motion dissociates from gaze direction, even though many subjects generated such movements in other paradigms. These experiments confirm the influence of stimulus luminance on comparative movement velocity, and demonstrate that the behavioural set assumed in this task discourages head-only errors.

Neuromuscular consequences of reflexive covert orienting.

Visual stimulus presentation activates the oculomotor network without requiring a gaze shift. Here, we demonstrate that primate neck muscles are recruited during such reflexive covert orienting in a manner that parallels activity recorded from the superior colliculus (SC). Our results indicate the presence of a brainstem circuit whereby reflexive covert orienting is prevented from shifting gaze, but recruits neck muscles, predicting that similarities between SC and neck muscle activity should extend to other cognitive processes that are known to influence SC activity.