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finding hidden bodies, believed to have been murdered and buried, is problematic, expensive in terms of human resource and currently has low success rates for law enforcement agencies. Here we present, for the first time, ten years of multidisciplinary geophysical monitoring of simulated clandestine graves using animal analogues. Results will provide forensic search teams with crucial information on optimal detection techniques, equipment configuration and datasets for comparison to active and unsolved cold case searches. electrical Resistivity (eR) surveys showed a naked burial produced large, lowresistivity anomalies for up to four years, but then the body became difficult to image. A wrapped burial had consistent small, high-resistivity anomalies for four years, then large high-resistivity anomalies until the survey period end. Ground Penetrating Radar (GPR) 110-900 MHz surveys showed the wrapped burial could be detected throughout. 225 MHz GPR data was optimal, but the naked burial was poorly imaged after six years. Results suggested conducting both eR and GpR surveys if the burial style was unknown when searching for interred remains. Surveys in winter and spring produced the best datasets, and, as post-burial time increases, surveying in these seasons became increasingly important. this multidisciplinary study provides critical new insights for law enforcement and families of the disappeared worldwide. Available statistics for missing persons globally vary. For example, in the United Kingdom, ~250,000 are reported missing every year, but, of those, only ~2,500 are still missing after a year 1. In the United States, ~650,000 are reported missing every year, but only ~90,000 are still missing after a year 2. Whilst these still missing numbers are comparatively small, for the families of the missing it is obviously of crucial importance for them to be found, not only for closure if they have been the victim of a homicide, but also to know that justice for the perpetrator(s) has been served. However, current success rates to find the missing are low, with high profile examples being Madeleine McCann in Portugal and Ben Needham in Greece, sadly both presumed dead. Forensic search methods vary widely. A search strategist may be involved in a case at an early stage to decide which methods would have the highest probability of search success 3 , but this is not for every case globally, and investigations may not be standardised or indeed different techniques undertaken, depending on local experience 4. Metal detector search teams 5-7 and specially-trained victim recovery dogs 7-9 are both commonly used during initial investigations or as part of phased sequential search programmes. Forensic investigators have been increasingly using geoforensic methods in civil or criminal forensic investigations, predominantly to assist search teams as they attempt to locate missing persons or for trace evidence purposes 10-13. Locating homicide victims buried within clandestine graves is one of the most important and difficult ch...

This ongoing monitoring study provides forensic search teams with systematic geophysical data over simulated clandestine graves for comparison to active cases. Simulated “wrapped,” “naked,” and “control” burials were created. Multiple geophysical surveys were collected over 6 years, here showing data from 4 to 6 years after burial. Electrical resistivity (twin electrode and ERI), multifrequency GPR, grave and background soil water were collected. Resistivity surveys revealed that the naked burial had low‐resistivity anomalies up to year four but then difficult to image, whereas the wrapped burial had consistent large high‐resistivity anomalies. GPR 110‐ to 900‐MHz frequency surveys showed that the wrapped burial could be detected throughout, but the naked burial was either not detectable or poorly resolved. 225‐MHz frequency GPR data were optimal. Soil water analyses showed decreasing (years 4 to 5) to background (year 6) conductivity values. Results suggest both resistivity and GPR surveying if burial style unknown, with winter to spring surveys optimal and increasingly important as time increases.

19Graveyards and cemeteries around the world are being increasingly designated as full. 20There is a growing requirement to identify burial spaces or to exhume and then re-inter 21 burials if necessary. Near-surface geophysical methods offer a potentially non-invasive 22 target detection solution; however there has been lack of research to identify optimal 23 detection methods using such geophysical techniques. This study has collected multi-24 frequency (225 MHz -900 MHz) ground penetrating radar, electrical resistivity and 25 magnetic susceptibility surface data over known burial sites with different burial ages and 26 UK church graveyards. Results indicate that progressively older burials are more difficult to 27 detect but successful grave detection is complicated by soil type. Different geophysical 28 techniques were optimal in the three sites surveyed, which therefore suggests a multi-29 technique approach should be utilised by survey practitioners. Graveyard geophysical targets 30 included the grave soil present above earth-cut graves, the grave contents themselves, brick-31 lining (if present) and grave soil leachate plumes that are all geophysically detectable from 32 background levels. Grave markers were also identified as not always being located where the 33 burials were positioned. This study clearly demonstrates the value of these techniques in 34 grave detection and inform search teams detecting clandestine burials. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Globally, graveyards and cemeteries are suffering from a severe lack of burial space. 42With an estimated 55 million individuals dying globally each year (de Sousa, 2015), the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 (Reynolds, 2011; Pringle et al. 2012a Pringle et al. /2016 Gaffney et al. 2015). Electrical resistivity 77 surveys have been successfully used to locate unmarked burials in cemeteries (see, e.g. 78Matias et al. 2006; Hansen et al. 2014; Buyuksarac et al. 2015). Controlled studies on 79 modern burials evidencing that decompositional fluids may be the dominant factor in graves 80 that is detected electrically (see Jervis et al. 2009; Pringle et al. 2012b), and may be retained 81 in grave soil for considerable periods of time post-burial (see Pringle et al. 2015a). However, 82it is important to note that the style of formal burials and clandestine graves of murder 83 victims are usually quite different in terms of structure, depth and complexity of the burial 84 contents (Fig. 1). Apart from graveyards and cemeteries being reused, partially excavated, 85topsoil removed, etc. the graves present can also vary in style from earth-cut (as shown in 86 Fig. 1) to...

Colombian forensic investigators required assistance locating clandestine burials of missing persons related to human right atrocities from 14 years ago. Geoscientific search methods were trialled, including a predictive spatial statistical model, using various input and database information, to select the most likely grave locations in difficult mountainous terrain. Groundwork using forensic geomorphology, near‐surface geophysics (ERT) and subsequent probing identified suspect burial positions. One site was in mountainous terrain and the other in former school grounds, both difficult to access and in poor weather conditions. In the mountainous area, a negative resistivity anomaly area was identified and intrusively investigated, found to be a buried rock. In school grounds, after MESP and intelligence were used to identify a burial site, surface depressions were identified, and ERT datasets collected over the highest priority depression; intrusive investigations discovered a hand‐dug pit containing animal bones. This approach is suggested for Latin American searches.

The Crossrail underground network extension discovered well preserved skeletons shallowly buried in Central London in 2013. Subsequent carbon dating and aDNA analysis confirmed the archaeological age and presence of the Yersinia pestis "Black Death" plague epidemic strain. Here we present the non-invasive multi-proxy geophysical survey of the adjacent Charterhouse Square, rapidly undertaken to detect any further burials and characterise the site. Historical records suggested the area was a burial ground for Black Death plague victims, before subsequent cemetery and urban land use. Following initial trial surveys, surveys imaged ~200 isolated and similar-sized burials in the southwest of the site. There were also two contrasting burial orientations present at various depths which suggested a series of controlled phased burials. A well-defined eastern burial boundary, taking the form of a ditch and bank, was also discovered. Geophysical surveys also identified a subsequent complex site history with multiple-aged features. This study revises knowledge of Black Death aged-burials and provides important implications for successful geophysical burial detection with significant time-and space-limited site constraints.

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There are various techniques available for forensic search teams to employ to successfully detect a buried object. Near-surface geophysical search methods have been dominated by ground penetrating radar but recently other techniques, such as electrical resistivity, have become more common. This paper discusses magnetic susceptibility as a simple surface search tool illustrated by various research studies. These suggest magnetic susceptibility to be a relatively low cost, quick and effective tool, compared to other geophysical methods, to determine disturbed ground above buried objects and burnt surface remains in a variety of soil types. Further research should collect datasets over objects of known burial ages for comparison purposes and used in forensic search cases to validate the technique. Suggested Reviewers:NOTICE: this is the author's version of a work that was accepted for publication in Forensic Science International. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Forensic Science International, v. 246, January 2015, doi:10.1016/j.forsciint.2014 AcknowledgementsAn EU ERASMUS student training award part-funded the placement of Matteo Giubertoni.A 2011 and 2014 U.K. Nuffield Foundation summer placement award funded the coastal and test hole studies respectively. The authors wish to thank the numerous physical science under-and post-graduate students at Keele University for undertaking pilot investigative projects. The Keele University meteorological observation station provided weather data for the campus case studies. John Cassella and Staffordshire University are thanked for provided facilities and logistical support for the urban case study. AcknowledgmentsThe use of magnetic susceptibility as a forensic search tool