The use of geoscience methods for aquatic forensic searches

Abstract

There have been few publications on the forensic search of water and fewer still on the use of geoforensic techniques when exploring aqueous environments. Here we consider what the nature of the aqueous environment is, what the forensic target(s) may be, update the geoforensic search assets we may use in light of these, and provide a search strategy that includes multiple exploration assets. Some of the good practice involved in terrestrial searches has not been applied to water to-date, water being seen as homogenous and without the complexity of solid ground: this is incorrect and a full desktop study prior to searching, with prioritized areas, is recommended. Much experimental work on the decay of human remains is focused on terrestrial surface deposition or burial, with less known about the nature of this target in water, something which is expanded upon here, in order to deploy the most appropriate geoforensic method in water-based detection. We include case studies where detecting other forensic targets have been searched for; from metal (guns, knives) to those of a nonmetallic nature, such as submerged barrels/packages of explosives, drugs, contraband and items that cause environmental pollution. A combination of the consideration of the environment, the target(s), and both modern and traditional search devices, leads to a preliminary aqueous search strategy for forensic targets. With further experimental research and criminal/humanitarian casework, this strategy will continue to evolve and improve our detection of forensic targets.

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

“…Every case is unique as discussed by many others (see ), but the case study presented here illustrates the advantages of the use of forensic geoscience techniques in the assistance of cold case investigators, to assess, characterize, and then carefully conduct invasive examinations of specified survey areas, as few other studies have done, although note Nobes’ efforts.…”

“…Obviously, no human remains were found in this cold case investigation. This is due to two reasons: either “Fred” was within the survey area specified and was not geophysically detectable using the search methods employed, or he was not present in the specified survey area. If was true, then other methods may have been useful to employ, for example, a more sensitive metal detector, or indeed a multifrequency GPR system, collecting GPR on an xy grid orientation, with the caveat that many more tree roots/boulders may be identified as geophysical anomalies.…”

“…The use of forensic geoscientific techniques and methods in the search for clandestinely buried objects is increasing, as locating forensically important materials is crucial for criminal convictions to proceed (1). Current forensic search methods to detect both isolated and mass clandestine burials of murder victims are highly varied and have been reviewed elsewhere (1,2), with best practice suggesting a phased approach, moving from large-scale remote sensing methods (3) to ground reconnaissance and control studies before full searches are initiated (4). These full searches have involved a variety of methods, including forensic geomorphology (5), forensic botany (6) and entomology (7), scent-trained search dogs (8,9), physical probing (10)(11)(12), thanatochemistry (13,14), and near-surface geophysics (15)(16)(17)(18)(19)(20)(21)(22)(23).…”

Inorganic elemental analysis of decomposition fluids of an in situ animal burial

“…Geoscientific methods are being increasingly utilized by forensic search teams for the detection and location of clandestine burials [1][2][3]. Clandestine graves of murder victims are usually shallow, less than 3 m and typically 0.5 m below ground level (bgl) [4][5], but current detection rates are low and, without locating the victim's body, obtaining a successful conviction is more difficult [6][7].…”

“…This process occurs before determining search strategies, undergoing site reconnaissance and phased site investigations, and then intrusively investigating anomalous areas [2,6,8]. Geoscientific site investigation methods vary depending upon the specific case, search site, and numerous other factors that are reviewed elsewhere [2][3], but can include scent-trained human remains detection dogs [8][9], forensic geomorphology [10], forensic botany [11][12] and entomology [13-14, near-surface geophysics [15][16][17][18][19][20][21][22][23], intrusive probing [24][25] and soil geoscience analysis [26][27][28].…”