Search protocols for hidden forensic objects beneath floors and within walls

Abstract

The burial of objects (human remains, explosives, weapons) below or behind concrete, brick, plaster or tiling may be associated with serious crime and are difficult locations to search. These are quite common forensic search scenarios but little has been published on them to-date. Most documented discoveries are accidental or from suspect/witness testimony. The problem in locating such hidden objects means a random, or chance-based approach is not advisable. A preliminary strategy is presented here, based on previous studies, augmented by primary research where new technology or applications are required. This blend allows a rudimentary search workflow, from remote desktop study, to non-destructive investigation through to recommendations as to how the above may inform excavation. Published case studies on the search for human remains demonstrate the problems encountered when trying to find and recover sealed-in and sealed-over locations. Established methods include desktop study, photography, geophysics and search dogs: these are integrated with new technology (LiDAR and laser scanning; photographic rectification; close-quarter aerial imagery; ground-penetrating radar on walls and gamma-ray/neutron activation radiography) to propose this possible search strategy.3

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

“…Recent geophysical research using simulated clandestine graves have found optimal detection methods and configurations are highly variable, depending upon a host of factors, the most important deemed to be time since burial, burial style, local soil type, vegetation and climate [35,[43][44][45][46][47][48][49][50][51][52][53][54].…”

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

“…Near-surface geophysical methods rely on there being a detectable physical contrast between the target and the background (or host) materials (see [37]). 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]).…”

Avances De La Geología Forense en Argentina: Búsqueda Con Métodos No Invasivos De Personas Víctimas De Desaparición Forzada

“…Actualmente, se ha sumado el desarrollo de estudios geofísicos en fosas clandestinas de prueba para elaborar metodologías más precisas de ubicación de estos sitios y que aumenten la posibilidad de hallazgo considerando varios factores como antrópicos, de enterramiento y climáticos, entre otros (Davenport et al, 1992;Murray y Tedrow, 1992;Strongman, 1992;Pye y Croft, 2004;Ruffell y McKinley, 2008;Schultz, 2008;Schultz y Martin, 2011, 2012Pringle et al, 2012Pringle et al, , 2015Ruffell et al, 2014;Hansen et al, 2014). En Colombia los primeros ensayos empíricos para la ubicación de enterramientos clandestinos, fueron realizados aplicando métodos geofísicos en fosas simuladas, entre éstos: magnético, electromagnético, resistividad eléctrica y georradar (Molina et al, 2012(Molina et al, , 2015Molina, 2016).…”