Though terrain may differ, geoforensics knows no boundaries, as was demonstrated when UK and US geoscientists were invited to Colombia to help the fight against serious crime. Adler deWind reports.
Geoscientist 19.9 September 2009
Colombia, with a population of approximately 44 million, is a country that relatively few western geologists have visited. However, with careful planning, and in association with Colombian geologists and local logistical support, it is possible to visit Colombia safely and to participate in geological investigations - provided appropriate safety and security measures are taken.
In March this year, four geologists, two from the UK and two from the US, were invited to participate in the ‘first Ibero-American course on forensic geology’. We visited the headquarters of both the Colombian Police and National Forensic Crime Laboratories (Instituto Nacional De Medicina Legal y Ciencias Forenses) to give advice on those geological methods and techniques that may be used either to locate buried objects (such as homicide graves, mass genocide graves, firearms, explosive devises and drugs) or analyse rocks and soils so as to provide physical evidence that may link suspect or offender with a crime victim.
Colombian geoscientists are fast emerging as world-class geoforensic specialists and join a global trend, over the past few years, for geoscientists to be called in to support police and law enforcement agencies. In Colombia, with its long and complex crime legacy, there is a great need to bring those responsible for historical, recent and current crimes to justice. It is also desirable for graves and mass graves to be located so that family members can bring some closure to their suffering. Furthermore, buried explosive devices, weapons, firearms and illegal drugs require to be located, so as to hinder criminal activities by depriving them of resources.
The first Ibero-American course on forensic geology was organised by Dr Carlos Martín Molina Gallego and was held at the National University of Colombia’s Department of Geology, together with Colombia’s National Institute of Medical, Legal and Forensic Science from 30 March to 3 April, in Bogota. The course highlighted the significance and applications of geology to prosecutors, judges, lawyers, forensic scientists and the Colombian judicial police penal system.
Dr Laurance Donnelly, founder and chair of The Geological Society of London Forensic Geoscience Group, provided a series of lectures on: the importance of the development of a conceptual geological model to locate a homicide graves and buried objects, the development of search methodology, determination of search assets and techniques, the importance of effective communication between the police and geologists, regulation and accreditation, training needs for both police officers and forensic geoscientists, police protocols at crime scenes and case studies in geoforensics.
Other leading experts included US forensic geologists Dr Raymond Murray and Mr Bill Schneck, and Dr Alastair Ruffell, a geophysicist from Queens University, Belfast.
Dr Donnelly, Dr Murray (Missolua, Montana) and Dr Molina visited the Colombian Police at their Bogota HQ to gain a greater understanding of some of the challenges routinely facing Colombian police. This included addressing approximately 100 officers, and an inspection of the crime laboratories - where countless seized explosive devices, firearms and drugs are held. Some of the more recent anti-personnel mines are made from plastics, which make their detection more difficult. Colombian police officers face major challenges: including disarming criminal organisations, combating illegal trafficking of drugs across Colombia’s borders, and of firearms and weapons into Colombia (often in exchange). In addition, anti-personnel landmines and other explosive devices make some parts of Colombia too dangerous to visit - let alone undertake geological surveys. Furthermore, many of the homicide victims of Colombia’s violent past have been placed in unmarked graves, and many locations are suspected as locations of mass graves - the result of genocide.
Mr Schneck (Microvision Northwest-Forensic Consulting, Inc. and the Washington State Patrol Crime Laboratory, USA) and Dr Ruffell (Queens University Belfast) visited the ‘Instituto Nacional de Medicina Legal’ which is effectively Bogota’s forensic laboratory. Here, in touring its seven floors of labs, and seeing the view from the seventh floor (which gave a good feel for the layout of Bogota at the foot of the Andean mountain belt) they were left with a strong sense of the size of the problem that is being tackled.
How can geologists be of assistance? Laurance Donnelly explained: “Traditional police methods of finding graves often involves large-scale gridded areas with personnel ‘finger-tip/line searches’ and ‘trial-and-error’ excavations. These may be inefficient, cost prohibiting, often non-productive, labour intensive, may destroy evidence and ignore subtle ground disturbances. The search for a homicide victim’s grave is one for, rather than of, the crime scene. The aim is to progress the investigation by locating the victim using an offensive/detective search procedure. The objectives would be to obtain evidence for a prosecution, gaining further intelligence, and locating the remains of the victim. The search does not have the objective of the recovery of evidence or the victim.”
A conceptual geological model provides estimates of the target’s age; size and geometry; expected depth of burial; time and duration of burial; and physical, chemical, hydrogeological and geotechnical variations compared to the surrounding ground. A conceptual model of a potential burial site gives an estimate of what is likely to be found, and the condition of the target. Conceptual geological models are developed at the beginning of a search. It is a model to be tested, revised and tested again until it can be verified (at discovery) or proven otherwise and therefore abandoned. What is more, this model, developed originally by Dr Donnelly to search for graves in the UK, is applicable throughout the world.
The development of a geological model for a victim of homicide, or a grave, requires a specific understanding of the natural (geological) ground conditions and how these have been influenced by the activities of the offender such as, for example, digging and subsequent reinstatement of the disturbed ground. At any one location there are likely to be a number of interactive, dynamic, active surface geological processes, which have affected the rocks, soil, groundwater and topography. These processes were active long before burial took place and are likely to have continued in the time that has elapsed since the burial.
It is vital to acquire an understanding of the undisturbed (pre burial) and disturbed (post burial) geology and the target (no matter whether that target be drugs, firearms, human remains, explosives or money). Only then can investigators decide the correct search strategy, including choice of instrumentation, or identify the optimum method of deployment. Techniques may include geophysics, geochemistry, satellite imagery, air photo interpretation and invasive methods (such as auguring, drilling, trial pitting and trenching). Geological investigative techniques are applicable to law enforcement searches because their underlying search philosophy, concepts and principles are similar – i.e., there is a buried/concealed ‘object’ or ‘target’ desirable to be found.
“The most important services that a forensic geologist can give the police and a law enforcement search strategist are: the production of a geological model of a potential grave or burial site; an understanding of the geological and geomorphological processes; the characterisation and understanding of the origin, source and properties of the soils, rocks and target (body); and a choice of detecting methods” says Donnelly.
No single geological model suits all types of search areas and there is no single approach to producing a geological model, as each homicide case and search area will have unique characteristics. This is one of the primary roles for the geoscientist, which will vary from case to case. Geologists should not act alone when searching for grave or other buried objects, but form part of a multidisciplinary team of specialists.
“Geoscientists must recognise how their expertise and capabilities fit into the broader homicide investigation. For geoscientists involved in searching for victims of homicide, for example, their input may reduce once the target has been located, and the investigation moves into victim recovery and crime scene investigation. It is then important to hand over to other forensic practitioners in related sciences, such as forensic archaeology and anthropology, for victim recovery and post recovery analysis.”
Clearly, effective communication is crucial along with an understanding of other specialists’ skills and their limitations. Also important, for the forensic geoscientist, are the strict police protocols for the investigation of crime scenes and an appreciation of the judicial systems, unique to each country.
A meeting with the directors of the Instituto Nacional de Medicina Legal will form the basis of further collaboration, including exchanges of scientists between Colombia, the UK, USA and other countries now participating in the global network of contacts developed by
The Geological Society of London Forensic Geoscience Group.
“There is now a growing network of geoforensic specialists in academia, industry, consultancy, police, law enforcement and the military throughout the world. The success of the first Ibero-American course on forensic geology has brought Latin America into the global association of geoforensics” says Donnelly.
- The next major geoforensic conference is scheduled to be held in California in 2010 (please contact Marianne Stamm of the California Institute for Justice [[email protected]] for details. The Second Ibero-American course on Forensic Geology may be held in Brazil in 2011.