The use of magnetic susceptibility as a forensic search tool

Abstract

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

Preliminary results of sequential monitoring of simulated clandestine graves in Colombia, South America, using ground penetrating radar and botany

“…This was thought due to the smallest geophysical target, the depth of burial and relatively small contrast of dielectric permittivity between the human remains and the surrounding soil. It is suggested that perhaps magnetic geophysical methods may be useful to detect such burnt human remains as [68] successfully located Anglo-Saxon remains using this method and [72] shows magnetic susceptibility was a good detection technique to detect various simulated forensic targets although this has not been undertaken in this study.…”

The Search for “Fred”: An Unusual Vertical Burial Case,

“…Near-surface geophysical surveys have been used to try and locate clandestine graves in a number of reported criminal search investigations (17)(18)(19)(20)(21)(22)(23)25,26,(38)(39)(40)(41)(42). Geophysical surveys collected over simulated burials have also been undertaken to collect control data (e.g., [15,[43][44][45][46]). These control studies have shown that the geophysical responses in active cases could be predicted, although responses seem to vary both temporally after burial and between different study sites.…”

Geophysical monitoring of simulated homicide burials for forensic investigations

“…Near-surface geophysical methods need a detectable physical contrast between the target and background material 24 and have been used to locate clandestine graves of homicide victims in criminal search investigations 5,7,[25][26][27][28][29][30][31][32][33][34][35] . Geophysical surveys over simulated burials are undertaken to collect control data [36][37][38][39][40] and to predict what geophysical responses could be in search cases, although the actual response will vary both temporally and between study sites. A few geophysical control surveys have also collected repeat (time-lapse) data 16,29,[41][42][43][44][45][46] .…”