Abstract Using forensic soil science and forensic geology as trace evidence and searches for burials is the theme of the papers in this Special Publication. The concept and design of this volume was initially established by the International Union of Geological Sciences, Initiative on Forensic Geology, which successfully brought together forensic geologists, forensic soil scientists, police officers and law enforcement agents in the investigation of crimes. In this introductory paper a brief overview is provided of the developments in interdisciplinary knowledge exchange with use of soil and geological materials (known as ‘earth materials’) in the search for burials and the provision of trace evidence. The aim is to provide background information on the role and value of understanding ‘earth materials’ ranging from the landscape scale, to the crime scene through to microscopic scale investigations to support law enforcement agencies in solving criminal, environmental, serious and organized crime, and terrorism. In this connection, recent advances in field and laboratory methods are highlighted. Finally, the 20 papers in the volume are briefly introduced and these include a diversity of global operational case studies that involve collection and analysis of earth material from crime scenes and searches for homicide graves and other buried targets.

Abstract Soil science and geology are specialist disciplines that can make a valuable contribution to forensic science investigations. Despite a resurgence in earth material examination associated with criminal investigations, its full potential has probably not been realized. This paper discusses some of the issues that impact on the effective participation of soil science and geology in a broad forensic science context and why it is important for meaningful partnerships between forensic science service providers and specialist soil science and geology institutions to be established.

Abstract The desktop study of geology, past land use and recent surveys is essential in planning the search for buried items, as it provides information on ground conditions and may explain anomalies. In the first case study, a geophysical search of waste ground in west Belfast (Northern Ireland) identified two anomalies that on excavation were recovered as human skeletal remains. A desktop study, which included Ordnance Survey maps and memoirs, showed the location to have been next to a Jewish cemetery (1901–20), providing a reason for the human remains to be present. In the second case study, legal action was undertaken because a football ground suffered continual flooding. A desktop study preceded a geophysical survey that showed how the area was a former industrial works, infilled with sand but poorly drained, creating a ‘bowl’ into which urban drainage flowed, causing the flooding. The context of land-use change is an example of how useful such combined geological and historical studies can be (using spatial digital data in a GIS), regardless of the age of an object/area of potential forensic interest. A full desktop study should be carried out prior to any field survey to limit the chances of deploying incorrect search assets and misinterpreting discoveries.

Abstract Police in the UK received information that a person had been reported as missing. Despite a diligent search and investigation, the person was not found. Several years later police received intelligence giving the location of a grave believed to contain the remains of the person previously reported as missing and now believed to be a victim of homicide. This new information suggested the missing person had been murdered and their remains were buried in a shallow, unmarked grave. Following a systematic search, the murder victim's body was found at a shallow depth, less than 1 m. Following the forensic recovery of the body, soil samples were collected at, beneath the floor of the grave, along the strike of the grave, downslope and upslope. Analysis of the soil samples showed elevated levels of putrescine, at nearly 150 ppb in the soils beneath, downslope and for several metres upslope from the body at localities where detector dogs had showed an ‘interest’ before the grave was discovered. The mineralogical analysis, using integrated automated mineralogy and petrology detected the presence of diagenetic calcite in the soil profile beneath the grave. Additionally, the organic analysis detected the presence of elevated stanols at the grave and down slope.

Abstract Normally, when geoscientific methods are involved in forensic investigations, they are used to search for and excavate buried bodies. Recently, geoscientific methods have become relevant to not only finding the perpetrators in homicide cases including those in which there are buried bodies, but also in cases involving crimes against the environment, cultural sites and vandalism. Additionally, there are cases in which the discovery of an unexpected burial complicates an investigation. Analytical techniques developed throughout the twentieth century form the basis for recent advances that allow for the forensic geosciences to aid in such investigations. Case examples that demonstrate these advances will be presented.

Abstract Any archaeological site, according to the Brazilian Federal Constitution, is a patrimony of the Union; consequently, when crimes against this cultural patrimony occur, it becomes the responsibility of the Federal Police of Brazil. In 2013, there was a complaint to the Brazilian Federal Public Prosecutor's Office about the depredation of an archaeological site and forced withdrawal of the indigenous people because of the construction of a multimodal port in the city of Guaíra, in the state of Paraná, in southern Brazil. Thus, the Technical–Scientific Sector of the Federal Police Department, in partnership with Brazilian universities, used standard geophysical methods such as ground-penetrating radar (GPR) to investigate and locate buried archaeological targets. This paper discusses the results of 2D and 3D investigations in the Tekoha Jevy indigenous village, located in Guaíra County. In the field, 32 parallel sections of GPR data were acquired using 250 and 700 MHz shielded antennas. The results showed several anomalies, two of which were subjected to field checks using excavations, which revealed several artefacts such as ceramic fragments associated with ancient indigenous occupations on the banks of the Paraná River.

Abstract In most Latin American countries there are significant numbers of both missing people and forced disappearances, c. 84 000 alone in Colombia. Successful detection of buried human remains by forensic search teams can be difficult in varying terrain and climates. This paper reports on the geophysical and botanical monitoring of simulated clandestine graves in two different environments over 24 months to establish optimal detection methods and equipment configurations. Twelve clandestine burials were simulated at three different burial depths (0.5, 0.8 and 1.2 m) commonly encountered in Latin America. The simulated targets were three pig carcasses, three human skeletons, three graves with burnt human beheaded skeletons and finally three empty graves to act as control. Geophysical detection methods included ground-penetrating radar, magnetic susceptibility, bulk ground conductivity and electrical resistivity. Geophysical results showed that apparent electrical resistivity was optimal to detect targets (85% success) in semi-rural areas and ground-penetrating radar was optimal to detect targets (92%) in tropical rainforest areas, followed by magnetic susceptibility and bulk ground conductivity. Botanical results evidenced variations in both study sites, which should be noted by forensic search investigators, with rapid growth of Raphanus in the tropical rainforest graves and Malvaceae and Petiveria in the rural study site. This paper shows the importance of conducting long-term controlled studies to assist forensic search teams with expected results and optimum equipment configuration(s).

Abstract The aim of this paper is to provide a forensic geology standard operating procedure (SOP) for the collection of soil, for the detection of volatile organic compounds (VOC) and leachate associated with decomposing human remains in a shallow, unmarked, homicide grave. This assumes that human remains undergo partial or complete decomposition after burial and that the VOCs and leachate plumes generated subsequently migrate from the grave. These are expected to be influenced by several factors, including for example the cause of death, time elapsed since burial, climate and weather, topography, geological characteristics of the soils and bedrock, hydrogeology and taphonomy. This SOP has been used in a number of high-profile police and law enforcement searches (see for example Donnelly et al. 2020 . Analysis of soil following a police-led open area search and the recovery of a cold case homicide grave, Forensic Soil Science and Geology , 492 , https://doi.org/10.1144/SP492-2017-337 ). This approach remains experimental and further research and operational test work are recommended at known (recovered) homicide graves. This might become applicable as a future reconnaissance method applied to searches taking place over large areas to help reduce the preliminary search area where VOC and leachates are detectable.

Abstract Illicit trade in gold, mainly sourced from South America and Africa, is used to fund criminal activities such as the drug trade. Laundering money through the purchase of illicit gold, then having it refined and being paid for in clean funds is a major problem, and drives further growth in illicit mining. In order to restrict the influx of illicit gold into the legal domain, it is necessary to be able to identify the traded item as being of a licit or illicit nature. The only way that this can be done with any certainty is by determining, from its chemical composition, the source of the gold and the means by which it has been processed and upgraded. The example dealt with here shows how the use of compositional, processing and geological knowledge is able to discriminate gold from different origins. Data derived from a physical sample is far better able to constrain the source than a paper trail of certification, which can be manipulated.

Abstract This paper presents the investigation of fraud and of the theft of metal acquired by a Brazilian company from a Chinese supplier. Zinc ingots were transported by ship from China to the city of Londrina, in Paraná State, Brazil. However, they were substituted at some point during their journey, and replaced with bags containing fine crushed rock. In this case of a classic ‘substitution’ it was possible to use geological methods to investigate the crushed rock. As such, the mineralogical, petrological and isotope analysis showed the replaced rock did not originate from a Brazilian provenance. Therefore, the substitution possibly occurred before the cargo's arrival in Brazil. An inadequate chain of custody of the cargo, during transportation from Asia to Brazil, including the onward journey from Paranaguá to Londrina, is likely to have provided the opportunity for the material exchange to take place. Collaboration between the Brazilian Federal Police and geological experts based in academia enabled the crime to be investigated and solved.

Abstract Soil examination can provide useful forensic information about the spatial location and human activities of a suspect. Soil is widely used in criminal investigations. In a case that occurred in the countryside of Jilin Province, in the NE of China, soil was found adhering to clothing on a body. Examination of plant debris in the soil using plant DNA barcoding technique found it to be ginseng root, which indicated that the soil might have come from a ginseng plantation. In the first instance, it helped in finding the place where the body was initially buried. Then a comparison was made between the soil recovered from the body and from the ginseng plantation. Composite analysis of minerals, pollen types and elements provided additional information to assist in making comparisons. Trace amounts of soil located on the body played an important role in locating the burial site and was regarded as the most valuable evidence in convicting the suspect of murder even without the suspect's DNA being available.

Abstract In a 2007 homicide in Western Australia, small (<0.5 mm diameter) red brick fragments and soil were identified on the victim's clothing (mainly bra), body (mainly hair) and vehicle. A comparative study of the mineralogy and morphology of the red brick fragments with red bricks from the paved area in front of the victim's house was undertaken by traditional laboratory X-ray diffraction (XRD) using low background Si wafer holders and a 0.5 mm focusing monocapillary attachment. Whilst significant similarities were observed between the two datasets, peak overlaps and poor resolution prevented a specific provenance to be determined. Additional analyses using the superior intensity and resolution of synchrotron XRD that was conducted at the Australian Synchrotron quantified the mineralogy of polycrystalline minerals (cristobalite and mullite) in the small brick fragments. These data established that the brick fragments could not be distinguished from the driveway bricks and were clearly shown to be different to a range of other possible sources. The trial was before a judge only and he concluded that the mineralogy data from the small brick fragments on the victim's clothing and the bricks from her front driveway indicated that she was initially attacked in her front yard and not at Kings Park where her body was buried.

Abstract Soil traces can be used as evidence in criminal investigations due their transferability, great variability and persistence. The soil samples originated from a crime scene that occurred in the Curitiba Metropolitan Region, Brazil. Physical, chemical and mineralogical analyses were carried out on the soil samples. All results were statistically analysed using multivariate analysis (PCA) to verify the relative positioning of soil traces which had been recovered from a stolen safety deposit box (SDB) from a vehicle suspected of being used in the SDB transportation, and from the site allegedly used in the opening of the SDB. The methods employed were effective in discriminating between the sampling sites. The soil from the site used in the opening of the SDB could be excluded as being the location where the soil transferred to the SDB had originated as it was different in many characteristics.

Abstract In a cold case investigation of a 1983 homicide, trace amounts of soil were identified on a 10-year-old victim's pyjama top. Swatch samples were cut from the pyjama top, specifically the hem, to determine the provenance of this questioned soil. A comparative study was undertaken of the questioned soil with control soils from the Onkaparinga estuary using morphological observations with the naked eye and scanning electron microscopy (SEM), chemistry, traditional laboratory X-ray diffraction (XRD) and synchrotron µ-XRD. Synchrotron µ-XRD with high-intensity X-rays provided greater sensitivity and resolution than the laboratory XRD source to identify pyrite and clay minerals on the pyjama top. SEM confirmed that these mineral particles are deeply impregnated in gaps between fibres of the fabric, which are likely to have originated under water with force being applied on the pyjama top – implying that the victim was pushed into the mud. This is substantiated by transference shaking experiments, where mineral particles are dominantly located on the surface of the fabric. The questioned soil samples have a moderately strong degree of comparability with the control hypersulphidic subaqueous soils containing pyrite in the Onkaparinga River estuary – providing evidence that the soils have similar origins. The accused was found guilty by a Supreme Court judge of murder.

Abstract Forensic investigations in Italy have no geoforensic protocols or standard protocols to provide the country's law enforcement agencies with the materials to create a multidisciplinary approach to crime scene investigation, using the correct personnel and appropriate tools. Several factors contribute to this situation in Italy, but the main two are: (i) a lack of education, which allows the CSI effect to spread at all levels of society; and (ii) a lack of proper financial and environmental resources to support research. Moreover, the stressful context and psychological pressure of working in such an environment impedes the creation and implementation of proper protocols and standard procedures to the level attained in other more famous forensic sciences.

Abstract Miniaturization of components and other advances in technology have resulted in significantly increased availability of portable X-ray fluorescence spectroscopy (PXRF) units, leading to a boom in their use in a variety of fields. An unfortunate corollary, however, is that there has also been a boom in the publication of data of doubtful quality, based on misunderstandings of PXRF and the underlying physics of X-ray fluorescence. Many manufacturers sell the units as point-and-shoot black boxes, capable of generating usable data under a range of conditions but, in reality, all of the assumptions and limitations inherent in laboratory-based XRF systems still apply or are even amplified in portable units. This paper highlights some of the areas of highest concern to alert readers and practitioners alike, and provides examples of some issues that may arise during analysis.

Abstract Unsolved crimes add significant financial, legal and social costs to the community. Therefore, there is an urgent need to develop robust solutions to deal with this growing issue. Soil forensic analysis is an emerging cross-disciplinary science that can deliver powerful physical evidence with significant benefits to criminal, counter-terrorism and environmental crime investigations. Technologies currently used, which are largely dependent on the examination of inorganic soil components, are unable to successfully resolve approximately 20% of soil comparisons in cases due to a deficiency in spatial resolution. The organic component of soil includes a vast number of living organisms, and the combination of these organisms can provide a biological signature to assist with soil comparisons. Recent developments in DNA sequencing technology enable characterization, and comparison, of these complex soil communities, providing additional discriminatory information that could potentially assist in cases that cannot currently be resolved. DNA analysis is routinely applied in forensic science to answer human- and non-human-related questions. This paper provides a broad overview of forensic DNA analysis, and describes the differences between DNA analysis of single specimen and complex soil DNA mixtures. We also highlight key areas of future research required for this technique to be fully utilized in casework.

Abstract The use of soil evidence to identify an unknown location is a powerful tool to determine the provenance of an item in an investigation. We are particularly interested in the use of these indicators in nuclear forensic cases, whereby identification of locations associated with, for example, a smuggled nuclear material, may be used to indicate the provenance of a find. The use of soil evidence to identify an unknown location relies on understanding and predicting how soils vary in composition depending on their geological/geographical setting. In this study, compositional links between the mineralogy of 40 soils and the underlying bedrock geology, as documented in local-scale geological maps, were established. The soil samples were collected from locations with broadly similar climate and land use across a range of geological settings in a ‘test bed’ 3500 km 2 area of SW England. In this region, the soils formed through chemical weathering of the bedrock, representing a worst case scenario for this type of forensic geolocation owing to the high degree of alteration of the parent rock during soil formation. The mineralogy was quantified using automated scanning electron microscopy–energy dispersive X-ray spectrometry analysis based on QEMSCAN technology. Soil mineralogy and texture as measured using this technique are consistent with the underlying geology as indicated by regional-scale geological mapping. Furthermore, differences between individual units of the same bedrock lithology, such as different granites, were identified by examining trace mineralogical signatures. From an investigative viewpoint, this demonstrated that rapid automated mineral profiling of soil samples could be used, in conjunction with readily available geological mapping or similar datasets, to provide indication of the areas from which a soil sample of unknown origin could, or could not, have been sourced.