A technical protocol for using ground penetrating radar and electrical resistivity tomography in the search for covert graves

The location of covert graves is an important but challenging part of missing persons investigations. Although traditional search techniques, such as foot searches and cadaver dogs, have proved successful, the incorporation of higher technology methods, such as geophysical techniques, can be used to increase the chances of locating covert graves. This article will present a field method for the use of two geophysical techniques, including ground penetrating radar and electrical resistivity tomography, which can successfully locate covert graves in an Australian environment. If the soil and climate conditions permit, this technical protocol can be applied to other clandestine grave search sites as well. Ultimately, by increasing chances of locating the covert grave, and by extension the missing person, a successful judicial outcome can be achieved and highly sought after answers can be provided to the family

Forensic interpretation framework for body and gait analysis:feature extraction, frequency and distinctiveness

Surveillance is ubiquitous in modern society, allowing continuous monitoring of areas that results in capturing criminal (or suspicious) activity as footage. This type of trace is usually examined, assessed and evaluated by a forensic examiner to ultimately help the court make inferences about who was on the footage. The purpose of this study was to develop an analytical model that ensures applicability of morphometric (both anthropometric and morphological) techniques for photo-comparative analyses of body and gait of individuals in CCTV images, and then to assign a likelihood ratio. This is the first paper of a series: This paper will contain feature extraction to observe repeatability procedures from a single observer, in turn, producing the frequency and distinctiveness of the feature set within the given population. To achieve this, an Australian population database of 383 subjects (stance) and 268 subjects (gait) from both sexes, all ages above 18 and ancestries was generated. Features were extracted, defined, and their rarity viewed among the developed database. Repeatability studies were completed in which stance and gait (static and dynamic) features contained low levels of repeatability error (0.2%–1.5 TEM%). For morphological examination, finger flexion and feet placement were observed to have high observer performance.</p

Geomatic techniques in forensic science: A review

The purpose of this review paper is to highlight various geomatic techniques that crime scene reconstructionists or forensic practitioners can use to document different kinds of scenes, highlighting the advantages, disadvantages, and when best to use each technology. This paper explores geomatic techniques such as a total station, photogrammetry, laser scanners and structured light scanners and how they can be used to reconstruct crime scenes. The goal of this paper is not to discredit manual methods, as they are long standing and reliable, but instead to shed light on alternative methods that may produce equally or more accurate results with a more visually appealing final product. It is important for law enforcement and forensic professionals to understand the advantages and disadvantages of each technique, knowing when certain techniques should be used (and when they should not), and being able to revert to traditional methods if required

Using Ground Penetrating Radar and Resistivity Methods to Locate Unmarked Graves: A Review

The location of unmarked graves in forensic and archaeological investigations is legally and culturally important. In a forensic context, locating covert burials of missing persons can provide closure to the family, as well as facilitating the successful prosecution of the individual(s) responsible. Archaeologically, burials provide an important source of information about health, diet, physical anthropology, and culture. Despite the importance of these features, the location of unmarked graves with conventional archaeological and forensic techniques, such as excavation, is difficult and expensive. As a result, geophysical techniques have been widely applied to the location of unmarked graves as they are non-invasive, cost and time effective, and avoid the unnecessary disturbance of human remains. This article brings together the literature on ground penetrating radar (GPR), and two resistivity methods, electrical resistivity tomography (ERT) and fixed probe resistivity (FPR), on their ability to locate burials and reviews their use in forensic and archaeological investigations. This paper aims to provide law enforcement personnel, archaeologists, geophysicists, and interested academics with an overview of how these techniques work, how they have been previously applied to grave detection, and the strengths and weakness of these methods

Post-mortem movement and skeletal disarticulation after death

Post-mortem movement relating to the disarticulation or positional change of entire limbs is relevant to a forensic investigator when examining a deceased person. Understanding that the position a body is found is not necessarily the way it was left changes the approach an examiner must take when investigating any death. This study quantified post-mortem movement of a human donor decomposing in an Australian environment over 16 months: 1) progressive measurement of the angles of joints; and 2) distance of separation between the articulating points of bones. ImageJ software was used to calculate angles and the distances between structures from time-lapse images. Movement was detected at all joints of the upper and lower limbs, occurring at all stages of decomposition across the study. Significant movement of the joints occurred as a result of bloat during the early stages of decomposition, and again during the advanced stages of decomposition as the soft tissue desiccated. Disarticulation was observed in the late stages of decomposition in all limbs and was not exclusive to short or long bones. Disarticulation also generated significant movement between skeletal structures in late decomposition. The results demonstrate that it is essential to consider post-mortem movement when investigating unexplained deaths

Changes in the morphometric characteristics of tattoos in human remains

Tattoos are secondary identifiers that can be used to provide a presumptive identity and provide information about a deceased individual to a case. Additional information may be available through the analysis of the visual presentation of tattoos. The aim of this study was to examine the morphological changes of tattoos during the decomposition of a human donor in an Australian environment. Using time-lapse cameras recording for 16 months, stills were extracted and tattoos were quantified using ImageJ. A full analysis was completed on three tattoos, while a fourth tattoo was partially analysed. The tattoos showed the most change in area during the bloat stage of decomposition, staying relatively constant in size for the remainder of the study. The detailed shape of the outlines showed the morphological effect of desiccation as part of decomposition and continued to change until the tattoo was no longer visible. Of the tattoos fully analysed, two became redundant as secondary identifiers on day 294, the other on day 333, all due to lack of visibility. This information is useful during investigations of unknown deceased persons; in this case, the stage of decomposition influenced the presentation of the tattoo

More than an offender location tool: Geographic profiling and body deposition

In homicide cases, it is difficult to provide resolution for the bereaved or to obtain a successful criminal conviction of the guilty party when no body is found. Since the mid-nineteenth century, geographic and environmental patterns have been used to better understand the relationship between crime and its environment. Now known as geographic profiling, practitioners in this field amalgamate criminological, psychological, and geographical knowledge, as well as aspects of mathematics, statistics, and physics to identify spatial patterns associated with criminal behaviour as a means of locating anchor points of an offender (where they live, or work). The same techniques can also be used to locate the covert body deposition sites of their victims. This paper aims to (1) provide a brief summary of criminal behaviour and the environment and how understanding their relationship can be helpful to geographic profiling, (2) amalgamate the available literature on the application of geographic profiling in locating clandestine graves (as most documented uses are to locate offender residences), and (3) include a geographic profile of Ivan Milat, an Australian serial killer (officially) active from 1989 to 1992, demonstrating how geographic profiling techniques can help to identify additional victims and potential body deposition sites. The information in this review will be helpful to law enforcement and practitioners to improve missing persons investigations and searches for clandestine graves

Forensic interpretation framework for body and gait analysis: feature extraction, frequency and distinctiveness

Surveillance is ubiquitous in modern society, allowing continuous monitoring of areas that results in capturing criminal (or suspicious) activity as footage. This type of trace is usually examined, assessed and evaluated by a forensic examiner to ultimately help the court make inferences about who was on the footage. The purpose of this study was to develop an analytical model that ensures applicability of morphometric (both anthropometric and morphological) tech-niques for photo-comparative analyses of body and gait of indivi-duals in CCTV images, and then to assign a likelihood ratio. This is the first paper of a series: This paper will contain feature extraction to observe repeatability procedures from a single observer, in turn, producing the frequency and distinctiveness of the feature set within the given population. To achieve this, an Australian popula-tion database of 383 subjects (stance) and 268 subjects (gait) from both sexes, all ages above 18 and ancestries was generated. Features were extracted, defined, and their rarity viewed among the developed database. Repeatability studies were completed in which stance and gait (static and dynamic) features contained low levels of repeatability error (0.2%–1.5 TEM%). For morphological examination, finger flexion and feet placement were observed to have high observer performance

Data associated with 'Comparison of time-lapse ground-penetrating radar and electrical resistivity tomography surveys for detecting pig (Sus spp.) cadaver graves in an Australian environment’'

Locating clandestine graves presents significant challenges to law enforcement agencies, necessitating the testing of grave detection techniques. This experimental study assesses the effectiveness of time-lapse ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) in detecting pig burials as simulated forensic cases. The research addresses three key questions: 1) observability of graves using GPR and ERT, 2) changes in geophysical responses over time, and 3) suitability of GPR and ERT as search techniques for covert graves. The results reveal that both GPR and ERT can detect graves; however, ERT demonstrates greater suitability in homogeneous soil and anomalously wet climate conditions, with detectability affected by grave depth. Additionally, resistivity values are influenced by soil moisture and decomposition fluids. The findings underscore the significance of site-specific factors when employing GPR and/or ERT for grave detection, including soil homogeneity, climate conditions, water percolation, and body decomposition state. These findings offer practical insights for law enforcement agencies dealing with homicide cases involving covert graves

A technical protocol for 3D observation and documentation of human decomposition

The changes that occur to the human body after death reflect a multitude of complex biological processes, which can be impacted by a collection of variables that are not yet fully understood. Typically, information is obtained through in-situ examination and/or 2D data collection, which may restrict the availability of data and prevent collection of valuable information. To address this gap, the aim of this paper is to present a protocol for 3D data collection of human decomposition in outdoor environments. The specific objectives include presenting an approach and framework using wildlife cameras and performing 3D observation of a decomposing body. The method includes the design and construction of a walk-in cage including five frames holding 31 cameras, installed at the Australian Facility for Taphonomic Experimental Research. Preliminary trials completed on one subject in Zurich and various objects provided promising results through the generation of a 3D model. Comparing the wildlife cameras 3D model with a high-quality 3D model showed only minor discrepancies. This approach will be used in a study designed to improve our understanding of the human decomposition process to ultimately assist investigators with PMI estimations and to help reconstruct the sequence of events and time of death. © 2022 Australian Academy of Forensic Sciences