The suitability of using domestic pigs (Sus spp.) as human proxies in the geophysical detection of clandestine graves.

Research in many forensic science fields commonly uses domestic pigs (Sus spp.) as proxies for human remains, due to their physiological and anatomical similarities, as well as being more readily available. Unfortunately, previous research, especially that which compares the decompositional process, has shown that pigs are not appropriate proxies for humans. To date, there has not been any published research that specifically addresses whether domestic pigs are adequate human proxies for the geophysical detection of clandestine graves. As such, the aim of this paper was to compare the geophysical responses of pig cadavers and human donor graves, in order to determine if pigs can indeed be used as adequate human proxies. To accomplish this, ground penetrating radar (GPR) and electrical resistivity tomography (ERT) responses on single and multiple pig cadaver graves were compared to single and multiple human donor graves, all of which are in known locations within the same geological environment. The results showed that under field conditions, both GPR and ERT were successful at observing human and pig burials, with no obvious differences between the detected geophysical responses. The results also showed that there were no differences in the geophysical responses of those who were clothed and unclothed. The similarity of the responses may reflect that the geophysical techniques can detect graves despite what their contents are. The study implications suggest that experimental studies in other soil and climate conditions can be easily replicated, benefiting law enforcement with missing persons cases.

Identification parade in immersive virtual reality - A technical setup.

Virtual Reality (VR) has sparked interest within the forensic community, where it is currently used for training purposes and in variety of forensic scenarios. In combination with efficient and user friendly full body 3-Dimensional (3D) documentation methods, VR visualisations present a viable tool for suspect witness identification. The well-known procedure of placing several persons in a room with a one-way-mirror, along with a witness on the other side of the mirror has practical disadvantages. The primary concern implicates the witness(s) and person(s) of interest coming face-to-face prior to the line-up, combined with finding sufficient persons to include within the line-up. Although image identification using printed paper partially resolved this problem, features such as body stature also marks an issue for the recognition and identification process. To test whether VR provides the technical capabilities to perform an identification parade, a total of 15 subjects were 3D documented using the multi-camera device "Photobox". From this group, one of the documented persons then interrupted a lecture, where consequently, the students were asked afterwards to identify the same person in VR and paper identification sets. It was found that the participating students were able to identify the "suspect" in both datasets. The results imply that VR technology allow users to identify persons. However, as this is a preliminary study the similarity problem was not analysed in this paper and requires further investigation to demonstrate the robustness of this approach.

The forensic holodeck - Recommendations after 8 years of experience for additional equipment to document VR applications.

The forensic holodeck was first introduced in 2013, using the first upcoming commercially available virtual reality gaming headsets to visualize forensic 3D reconstructions. Following the publication of this development virtual reality was introduced in case work in a variety of different ways. After 8 years of using virtual reality in a professional forensic capacity this professional practice report will show, which equipment is necessary in addition to a virtual reality setup. This mostly includes audio-visual and broadcasting technology for complete documentation of the application of virtual reality, but also some other IT equipment, which should be available for as low as 20'000 US$. Guidelines, hints and tips regarding equipment acquisition, setup and use will be provided and discussed.

An algorithm for automatically generating gas, bone and foreign body visualizations from postmortem computed tomography data.

Post mortem computed tomography (PMCT) can aid in localizing foreign bodies, bone fractures, and gas accumulations. The visualization of these findings play an important role in the communication of radiological findings. In this article, we present an algorithm for automated visualization of gas distributions on PMCT image data of the thorax and abdomen. The algorithm uses a combination of region growing segmentation and layering of different visualization methods to automatically generate overview images that depict radiopaque foreign bodies, bones and gas distributions in one image. The presented method was tested on 955 PMCT scans of the thorax and abdomen. The algorithm managed to generate useful images for all cases, visualizing foreign bodies as well as gas distribution. The most interesting cases are presented in this article. While this type of visualization cannot replace a real radiological analysis of the image data, it can provide a quick overview for briefings and image reports.

Quantifying human post-mortem movement resultant from decomposition processes.

BACKGROUND: Post-mortem movement is highly significant in unexplained death investigations, as body position or the position of remains helps to determine cause and manner of death, as well as potentially the circumstances surrounding death. Therefore, understanding post-mortem movement is of forensic relevance in death scene assessments. PURPOSE: The aim of this study was to quantify post-mortem movement in anatomical structures of a human donor during decomposition in an Australian environment, an evaluation that has not previously been undertaken. METHODS: The aim was achieved using time-lapse images of a human donor decomposing in order to capture the post-mortem movement over a 16-month period. Megyesi et al.'s [1] total body score system was used to quantify the decomposition of the donor in each image to determine the decomposition stage. ImageJ software was used to determine the distance from static landmarks to anatomical structures of interest in each image to allow for quantification. RESULTS: Early decomposition progressed rapidly, and advanced decomposition plateaued at 41 post-mortem interval days with a total body score of 24. The results support the conclusion that post-mortem movement does occur in all limbs of the donor. The anatomical structure that produced the most movement was the right styloid process of the radius, moving a total distance of 51.65 cm. A surprising finding of the study was that most post-mortem movement occurs in the advanced decomposition stage, with the lower limbs being the most active. CONCLUSION: This study supports that post-mortem movement can be quantified using time-lapse imagery, with results supporting movement in all limbs, a process that was active for the entire study period. An interesting finding was that the decomposition plateaued in the advanced stage with the donor remaining in mummification, and not reaching skeletonization after 16 months in situ. These findings are of significant importance to police in death scene assessments and forensic investigations.

Forensic gait analysis - Morphometric assessment from surveillance footage.

Following the technological rise of surveillance cameras and their subsequent proliferation in public places, the use of information gathered by such means for investigative and evaluative purposes sparked a large interest in the forensic community and within policing scenarios. In particular, it is suggested that analysis of the body, especially the assessment of gait characteristics, can provide useful information to aid the investigation. This paper discusses the influences upon gait to mitigate some of the limitations of surveillance footage, including those due to the varying anatomical differences between individuals. Furthermore, the differences between various techniques applied to assess gait are discussed, including biometric gait recognition, forensic gait analysis, tracking technology, and marker technology. This review article discusses the limitations of the current methods for assessment of gait; exposing gaps within the literature in regard to various influences impacting upon the gait cycle. Furthermore, it suggests a 'morphometric' technique to enhance the available procedures to potentially facilitate the development of standardised protocols with supporting statistics and database. This in turn will provide meaningful information to forensic investigation, intelligence-gathering processes, and potentially as an additional method of forensic evaluation of evidence.

Evaluating the utility of time-lapse imaging in the estimation of post-mortem interval: An Australian case study.

Estimating post-mortem interval is an important aspect in forensic investigations. The aim of this study was to investigate if time-lapse imaging can be used to improve estimates of post-mortem interval using Megyesi et al.'s [1] method for a human donor decomposing in an Australian environment. To achieve this, time-lapse images were taken every 30 min over a 6-month period. The Megyesi et al. [1] total body score (TBS) system was used to quantify the level of decomposition of the donor for each image. Linear regression was performed to determine if observing decomposition more than once a day leads to increased accuracy in predicting PMI (post-mortem interval). Decomposition initially progressed quickly and then plateaued at 1004 hours PMI, with a TBS of 24. Individual timestamps were created from the time-lapse images taken each day at 08:00 hrs, 11:00 hrs, 14:00 hrs, 15:00 hrs, and 17:00 hrs. All timestamps produced R2 values > 0.80, indicating that the Megyesi et al. [1] method accurately predicts PMI for this donor. The 08:00 hrs timestamp had the highest value R2 = 0.886, whilst the combined timestamp (which included the scores from all five images for each 24-hour period) R2 = 0.823 was the lowest. This study supports the validity of Megyesi et al.'s [1] TBS model to estimate PMI. Two other interesting findings were that the results suggest that scoring TBS multiple times per day does not improve estimates of PMI, however scoring TBS at daybreak produces more accurate results than scoring TBS later in the day. This may be an important consideration in forensic scenarios.

Forensic image analysis - CCTV distortion and artefacts.

As a result of the worldwide deployment of surveillance cameras, authorities have gained a powerful tool that captures footage of activities of people in public areas. Surveillance cameras allow continuous monitoring of the area and allow footage to be obtained for later use, if a criminal or other act of interest occurs. Following this, a forensic practitioner, or expert witness can be required to analyse the footage of the Person of Interest. The examination ultimately aims at evaluating the strength of evidence at source and activity levels. In this paper, both source and activity levels are inferred from the trace, obtained in the form of CCTV footage. The source level alludes to features observed within the anatomy and gait of an individual, whilst the activity level relates to activity undertaken by the individual within the footage. The strength of evidence depends on the value of the information recorded, where the activity level is robust, yet source level requires further development. It is therefore suggested that the camera and the associated distortions should be assessed first and foremost and, where possible, quantified, to determine the level of each type of distortion present within the footage. A review of the 'forensic image analysis' review is presented here. It will outline the image distortion types and detail the limitations of differing surveillance camera systems. The aim is to highlight various types of distortion present particularly from surveillance footage, as well as address gaps in current literature in relation to assessment of CCTV distortions in tandem with gait analysis. Future work will consider the anatomical assessment from surveillance footage.