The use of forensic botany and geology in war crimes investigations in NE Bosnia

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1 Forensic Science International 163 (2006) The use of forensic botany and geology in war crimes investigations in NE Bosnia A.G. Brown * Palaeoenvironmental Research Group, School of Geography, Archaeology and Earth Resources, University of Exeter, Amory Building, Rennes Drive, Exeter EX4 4RJ, UK Received 24 March 2005; received in revised form 17 February 2006; accepted 5 May 2006 Available online 30 June 2006 Abstract From 1997 to 2002 the United Nations International Criminal Tribune for the former Yugoslavia (ICTY) undertook the exhumation of mass graves in NE Bosnia as part of the war crimes investigations aimed at providing evidence for the prosecution of war criminals in The Hague. This involved the location and exhumation of seven former mass graves (primary sites) dug following the fall of Srebrenica in July These primary mass graves were secretly and hurriedly exhumed three months later and most of the bodies or body parts transported and reburied in a large number of secondary sites many of which were subsequently exhumed by ICTY. The aim of the pollen and soil/sediment studies was to provide an environmental profile of the original site of the samples and use this to match the relocated bodies to the original mass graves. This was part of completing the chain of evidence, providing evidence of the scale and organization of the original atrocities and the subsequent attempts to conceal the evidence related to them. All the primary sites were located in areas of contrasting geology, soils and vegetation, and this allowed matching of the sediment transported in intimate contact with the bodies to the original burial sites, which in some cases were also the execution sites. In all, over 24 sites were investigated, over 240 samples collected and analyzed under low power microscopy and 65 pollen sub-samples fully analyzed. The pollen and sediment descriptions were used in conjunction with the mineralogy (using XRD) of primary and secondary sites in order to provide matches. These matches were then compared with matching evidence from ballistic studies and clothing. The evidence has been used in court and is now in the public domain. It is believed this is the first time environmental profiling techniques have been used in a systematic manner in a war crimes investigation. # 2006 Published by Elsevier Ireland Ltd. Keywords: Forensic palynology; Forensic geology; War crimes; Mass graves; Bosnia 1. Introduction In recent years the use of forensic geology and botany in criminal cases has increased in many parts of the world [1,2] although it has a much longer history [3]. The combination of geology and botany for provenancing is what has been termed environmental profiling [4] and it can be particularly valuable in providing strong circumstantial evidence linking a suspect or suspects to a scene of crime [4,5]. The basis of the combination of techniques, such as mineralogy and pollen analysis is to decrease the chances of a false match. Forensic geology can often provide strong provenancing power at the sub-regional or landscape scale and forensic botany can provide * Tel.: ; fax: address: a.g.brown@exeter.ac.uk. evidence at the spatial scale of the crime scene. This can be regarded as providing evidence of both the closeness of association (match) and the uniqueness of that association as formalized in a maximum likelihood ratio [6]. This paper presents a summary of the results of environmental profiling used as part of the forensic investigations of the war in the former Yugoslavia and is believed to be the first attempts to use such techniques in a war crimes context. 2. Exhumation sampling In 1997 the United Nations International Criminal Tribune for the Former Yugoslavia (UN ICTY) started exhumations of mass graves in NE Bosnia associated with the massacre of civilians in and around Srebrenica in July of It was known from intelligence that 3 months after the initial executions of civilians the original mass graves (primary sites) had been /$ see front matter # 2006 Published by Elsevier Ireland Ltd. doi: /j.forsciint

2 A.G. Brown / Forensic Science International 163 (2006) exhumed and the bodies transported over a 1 3 day period to a number of unknown secondary grave sites. During exhumations in 1997 a program of sampling soils and sediments associated with both primary sites and secondary sites was begun. The aim of this program was to link the secondary sites with primary sites so providing evidence of the original location of the burials as part of the war crimes indictments against individuals held in The Hague or on the ICTY wanted list. The data would also add evidential weight to the prosecution claims of the scale and organization of both the original crimes and attempts to conceal evidence. Mass graves were sampled during exhumation with small bulk samples being taken of both the grave fills and the country rock and soils surrounding the mass graves. In all five primary sites were sampled and 19 secondary sites. This work was done in conjunction with, but without any knowledge of, the results of other forensic investigations of clothing, documents and shell casings. All soils and sediments were also described using standard geological and soil description procedure [7]. Due to the high and variable alteration of sediments in the graves caused by the variable state of decomposition and saponification of bodies under different water-table conditions it was decided to concentrate on robust non-transient sediment and soil characteristics and specifically included foreign items, clasts, pollen and spores (palynomorphs) and sediment mineralogy. The combined use of these parameters has been shown to have high provenancing power with a low risk of error in criminal investigations under appropriate circumstances. Sampling took place at both primary and secondary sites. In each case a series of samples was taken from the fill of the grave (body part matrix) at locations both away from and close to body parts (Fig. 1). In many cases clasts of soil or mud could be recognized which had been mixed into the fill and these were sampled separately. Additional samples were taken from the cranium and between clothing, skin, or bone of certain of the bodies. Soil from these areas is unlikely to have been lost or gained during the process of exhumation. Additional control samples were taken from the walls of the grave once all the fill had been removed. At least one control sample was taken for every body-part matrix sample. These control samples represented the background pollen and spore accumulation profile for that location. This also allowed the determination of a mineral profile of the local soils and sediments. The local vegetation was also recorded to a distance of approximately 50 m where de-mining permitted. Vegetation was only recorded as presence or absence with additional comments on abundance for the major species present. The overall aim of the sampling strategy was to trace as many stages as possible on the chain of events that ended with the exhumation by ICTY and could have allowed the addition of soil and pollen. Overall over 240 samples were taken and 65 sub-samples counted in the pollen and spore analyses. 3. Methods Samples for pollen and mineralogical analysis were approximately 50 g and depending upon the context either cut from the walls of the excavations, from sections, or taken from clothing or direct body contact in the field or mortuary. The samples were inspected under low power magnification and then for pollen and spore analysis sub-samples were subjected to standard chemical procedures [8]. This involved the removal of carbonates using weak hydrochloric acid, triple sieving (7 mm), removal of silicates using hydrofluoric Fig. 1. The sampling contexts of the environmental investigations.

3 206 A.G. Brown / Forensic Science International 163 (2006) acid, the removal of organic matter using an acetylation mixture (sulphuric acid and acetic anhydride) and finally mounting in silicon oil. In most cases relatively large subsamples were used (1 3 ml) due to the probable variable pollen and spore concentrations of soils and sediments. Exotic marker spores were not added due to pollen and spore concentration values having little worth in such situations. Silicon oil was preferred to glycerol due to the anticipated difficulty of some identifications. Pollen and spore identification took place at 600 magnification and 1000 for critical identifications. An extensive reference collection held in the Palaeoecology Laboratory at Exeter was used to aid identification and standard pollen nomenclature is used [9]. Of particular importance was the differentiation of the cereal type pollen which was achieved using specialist keys [10,11] and which allowed the identification of Zea mays on the basis of its grain size (>60 mm) and its pore and annulus dimensions using [12]. Rosaceae pollen grains were differentiated using a combination of the above keys, [13] and the type collection at Exeter. Pollen and spore data were held on spreadsheets and the results summarized in the reports presented to ICTY. Samples were prepared for XRD by crushing with a pestle and mortar, homogenizing and smearing onto glass slides. XRD analysis utilized a Philips PW1830 generator which employed Philips APD software system to set parameters. All samples were analyzed using 40 kv, 40 ma Copper Ka radiation from a long fine focus tube with 18, 0.18 and 18 divergence, receiving and scatter slits, with samples run from 48 to 708 2u. The count rate was adjusted to 1.0 s with a step size of Only major mineral components were identified and used as this provides a more robust level of comparison and reduces the effect of local and within profile variation. North East Bosnia is a region of the central Balkan Mountains and the local geology is dominated by a series of thrusts extending E-W through the Zvornik area into Serbia (Fig. 2). This thrust zone is predominately composed of limestones and dolomites but there are also small outcrops of amphibolites and serpentinites. The thrust zone has also been intruded by igneous rock, such as lamprophyres, and there are dyke swarms. There is also extensive regional metamorphism throughout the area. To the south the geology is dominated by folded and variably metamorphosed sedimentary rocks including, sandstones, shales, conglomerates and schists. An exception to this is the Srebrenica area where there is a large mass of extrusive volcanics which include andesites, dacites and pyroclastics. North of the river gorge at Zvornik, the River Drina valley has a suite of terraces composed of sand and gravels. The soils in the area are essentially Mediterranean Brown Earths but there is a very strong lithological control producing calcareous Brown Earths and calcareous Pelosols on limestones, acid Brown Earths on the terraces and podzolic profiles on the sandstones, shales and schists. There is also a loessic input to many of the soils. The regional vegetation would naturally be central European montane beech and coniferous forest, and some woodland survives composed of Fagus, Carpinus, Quercus, and Pinus and Picea at higher elevations. However, the area has been extensively cultivated and there exists a patchwork of small unenclosed hay fields, small unenclosed arable fields, and orchards in the valley floors and lower valley sides, with woodland on the upper slopes. Only examples of the results Fig. 2. The geology of the area around Srebrenica. Adapted from the Geology Map of Yugoslavia, Yugoslavian Geological Survey, Belgrade.

4 A.G. Brown / Forensic Science International 163 (2006) Primary sites Fig. 3. Photograph of striated serpentinite clast from the fill of HZ 3. Scale in cm. can be listed here in order to illustrate the range of environmental evidence used. 4. Results Initial investigations of the sedimentology, clasts and included foreign bodies provided some initial linking evidence. For example, the discovery of a striated clast of serpentinite in secondary grave Hodzici road (HZ) 3 (Fig. 3) was found to match the local geology of only one of the primary sites (Lazete I) upslope of which was a serpentinite dyke. At secondary site HZ 5 sections of stretched black plastic piping were recovered which matched (including the extruded ends) with a water pipe which had crossed the primary site Lazete II prior to excavation of the mass grave. XRD analyses revealed that there was a major mineralogical difference between the primary sites. In particular Lazete II and I had swelling clay minerals present (Table 1) whilst Branjevo Farm and Glogova did not. These differences were clearly related to the soil and geology surrounding the primary sites which was in all cases different from that of the secondary sites. This provided a major differentiation between sediments derived from the primary sites. Additionally, foreign plant macrofossils could be recognized in several sites included clumps of matted hay which were found in intimate contact with body parts at both Glogova 1F, 1H, 8 and 9 (but not 1E) and at secondary sites such as Zelanji Jadar 6. The location and vegetation surrounding the Glogova sites was at variance with this find and the discovery of shell casings within masses of hay suggested it had originated at the location of execution, which on the basis of witness statements was believed to be the Krevice warehouse (Potocari). The pollen and spore counts were used to provide lists of types present with their relative percentages. The land use and vegetation of the primary sites was both surveyed in the field and known from aerial photographs. The major differences between the primary sites allowed relatively straightforward allocation based primarily on the dominant pollen and spore types recorded. The summarized profiles of the primary sites and linked secondary sites are given in Table 1 including the dominant vegetation and pollen and spore types. It should be noted that many other secondary sites exhumed were linked by using other evidence directly to primary sites or to the secondary sites listed below and thus to a primary site. As can be seen from Fig. 4 the gross types present at each of the primary sites varied significantly. At Branjevo Farm there were low tree values, high herbs (mostly Poaceae) and very Table 1 Summary of the environmental evidence linking primary and secondary sites Primary site Kozluk Branjevo Fm Lazete I Lazete II Glogova 1E Glogova 1F, 1H, 3, 5, 7, 8, 9 Soil type/lithology/ inclusions River terrace gravels, discoid fluvial gravel (imbricated) Tuff with deep loessic soils Thrust zone, limestone, dolomites, sandstones, serpentinite dyke Thrust zone, limestone, dolomites, sandstones, black water-piping Sandstones and siltstones with limestone rich gravel in places Sandstones and siltstones with limestone rich gravel in places, hay masses (some with shell casings), rubble, concrete, plaster Major minerals Vegetation/land use Dominant pollen/spores (in descending value) Ch, I/M, Qz, F, C Scrub/grassland and arable CR3 Ch, I/M, Ka, Qz, Fe Edge of arable field (wheat communal farm) ruderals S, I/M, Ka, Qz, Fe Edge of montane forest (10 m) S, I/M, Ka, Qz, Fe Clearing in the montane forest, wet meadow Qz, Ch, I/M Qz, Ch, I/M Mixed arable, hay meadow, orchards and forest (incl. pine, beech, hornbeam and spruce) Mixed arable, hay meadow, orchards and forest (incl. pine, beech, hornbeam and spruce) S: swelling clays; Ch: chlorite; I/M: illite/mica; F: feldspar; Ka: kaolinite; Qz: quartz; Fe: iron; C: calcite. Cereals, Poaceae, Pinus, Picea Pinus, Cyperaceae, Poaceae, Picea, Juglans Pinus, Cyperaceae, Poaceae, Picea, Juglans Fagus, Picea, Pinus, Carpinus, Corylus, Poaceae Trees, Pinus, Picea, herbs (high Poaceae) and high cereals (Avena/Triticum) occasional Z. mays, Malus t. and Prunus t. Linked secondary sites CR12 HZ3 HZ2, HZ4, HZ5 ZJ6 ZJ5

5 208 A.G. Brown / Forensic Science International 163 (2006) Fig. 5. Summary pollen data from the secondary grave sites. Fig. 4. Summary pollen data from the primary grave sites. high cereals whilst at Lazete I trees were dominant with moderate herbs and no cereals. This reflected the relative locations of the sites with the Branjevo Farm site on the edge of an arable field in an area of large fields (co-operative farm) with little tree cover whereas the Lazete sites were located at the edge of montane woodland. There were several primary sites at Glogova but the natural soil and sediment surrounding all the graves had pollen and spore contents too low to count (due to ploughing) and so pollen from sediments within the grave matrix had been brought in along with the topsoil and bodies. The vegetation surrounding the Glogova sites included a mix of woodland, orchards, hay meadows and arable fields. As can be seen from Fig. 4 the fill matrix of Glogova 1F, 1H, 8 and 9 all share similar pollen and spore spectra with relatively low trees, high herbs (mostly Poaceae) and high cereal types. However, Glogova 1E is entirely different with high trees (dominated by Fagus and Picea), very low herbs and only a trace of cereals. The Glogova 3 matrix samples suggested they were derived from an open environment, probably a meadow which has in the past been under cereal cultivation probably maize (Z. mays). The Glogova 5 matrix samples produced very similar pollen assemblages all dominated by cereals and pine pollen with a variety of meadow herbs and trees. The vast majority of the cereal pollen is maize (Z. mays), a pollen type which does not travel far. These samples are from a meadow which was under maize the previous year. At least a part of the field from which the soil comes was close to a walnut tree. The samples from Glogova 7 had very low pollen counts, but the pollen present was similar in types to Glogova 3 and 5. The most obvious characteristic of all the Glogova body part matrix samples with the exception of 1E was the high cereal pollen type, the majority being Avena Triticum type (probably wheat) with occasional Z. mays (maize) pollen grains. Cereal pollen grains are only found at such levels within wheat fields or where straw or grain is stored. Also in grave 1F a straw and hay-rich mass was observed and sampled (GL01/282A). The differences are Table 2 Major pollen type comparisons (in percentage total land pollen) for secondary sites along the Hodzici road Selected pollen and spore types Hodzici road 25 Hodzici road 23 Hodzici road 3 Hodzici road 4 Abies (fir) Alnus (alder) 2.4 Carpinus (hornbeam) Corylus (hazel) Fagus (beech) Juglans (walnut) 3.6 Picea (spruce) Pinus (pine) Quercus (oak) 1.1 Asteraceae (dandelion-like flowers) Cereals (cereals) 2.2 Chenopodiaceae (goosefoot family) 1.6 Cyperaceae (sedges) 2.0 Hedera (ivy) 1.3 Lactuceae (daisy-like flowers) Plantago lanceolata (ribwort plantain) Poaceae (grasses) Pteridium (bracken) Ranunculus t. (buttercup family) Reseda t. (mignonettes) 1.9 Vicia cracca (tufted vetch) 2.3 Filicales (unid. Ferns) 4.8 Others

6 A.G. Brown / Forensic Science International 163 (2006) Table 3 Major pollen and spore type comparisons in percentage total land pollen and spores for secondary sites at Zelanji Jadar Selected pollen and spore types Zelanji Jadar 5 AB13 control Zelanji Jadar 5 AB4 BPM Zelanji Jadar 5 AB1 BPM Zelanji Jadar 6 19A BPM (mixed) Zelanji Jadar 6 43A BPM Abies (fir) 4.0 Carpinus (hornbeam) 6.0 Corylus (hazel) 1.1 Fagus (beech) Picea (spruce) Pinus (pine) Populus (poplar) 2.0 Apiaceae peucedanum t (Hog s fennels) Artemisia (mugwort) 2.0 Asteraceae 1.0 (dandelion-like flowers) Caryophyllaceae 1.2 (pinks family) Cereals (cereals) Chenopodiaceae 3.1 (goosefoot family) Cyperaceae (sedges) 1.4 Lactuceae (daisy-like flowers) Morus (mulberries) + Polygonum persicaria t. 1.0 (redshank) Plantago lanceolata (ribwort plantain) Poaceae (grasses) Ranunculus t. 6.2 (buttercup family) Serratula t. 2.5 Filicales (unid. Ferns) 2.7 Others Zelanji Jadar 6 266A BPM Fig. 6. The links made between primary and secondary sites using pollen, spore and mineralogical evidence. BF: Branjevo Farm; D: Dulici (Dam sites); GL: Glogova; HR: Hodzici road; KBF: Kozluk bottle factory; KR: Kancari road; LZ: Lazete; NK: Nova Kasaba; P: Potocari (Krevice warehouse); ZJ: Zelanji Jadar.

7 210 A.G. Brown / Forensic Science International 163 (2006) believed to reflect a different original source with the bodies in graves Glogova 1F-9 having been transported from the Krevice warehouse (the execution site) whereas the bodies in Glogova 1E were the result of local killings. However, the general tree content and particularly fruit trees (Malus t. and Prunus t.) in the body matrix samples from one sample in grave 1H and the similarity of the mineralogy of the body part matrix and natural/ control samples indicates that the sediment that forms the body part matrix was of local origin. Whereas, several samples contained masses of hay (cut and dried grass) and pollen spectra dominated by Poaceae (including clumps from anthers). This apparent conflict is the result of the mixture of bodies with hay from the warehouse with the backfill of the sediments and soils at the Glogova sites 1F Results from the secondary sites The mineralogy and pollen/spores content of Kancari road (KR) 3, KR12, Hodzici road (HZ) 3, HZ 4, and HZ 5 indicates that in each case the grave matrix is foreign to the site and could not have originated in situ. The sediment characteristics of KR3 were entirely compatible with its having been derived from the gravel quarries near the Kozluk bottle factory and it could not have come from Branjevo Farm, Lazete or Glogova primary sites. For KR12 the pollen/spore content, the sediment type and the stubble all point to the source being Branjevo Farm primary site. The mineralogy, pollen/spores content, clast lithology and inclusions (e.g. severed water pipe) all point to Lazete II as the origin for HZ 3, HZ 4 and HZ 5, all of which have similar pollen spectra (Table 2). The bifaces/tools and igneous clast lithology further indicate that Lazete 1 was the source for HZ 3. Fig. 5 shows the variation in gross pollen type spectra for three secondary sites. It shows that the fill of Zelanji Jadar (ZJ) 5 contained both local sediment (similar to the surrounding controls and dominated by tree pollen) and a very different spectrum dominated by herbs (mostly Poaceae) and cereals (Table 3). The site was located within the beach dominated montane forest. The pollen from the body part matrix from ZJ 5 is similar to Glogova 3 and 5 and is consistent with it having been derived from the same locality. A similar mixed fill was found at ZJ 6 (ZJ6/028A). A rather different combination was found at HZ 3, where the body part matrix component was found to be a close match to Lazete I in both mineralogy and pollen content. All the secondary sites, on the basis of clast lithology, mineralogy and pollen and spore content, could be associated with matching primary sites (Fig. 6). 5. Conclusions Along with other forensic evidence (clothing, personal effects, ballistics and documents), the environmental data provided a high level of multiple circumstantial evidence which linked the secondary sites to the primary sites and execution sites. The robustness of the evidence was revealed by its agreement with the other forensic evidence, particularly that derived from shell casings as no discrepancies were found between secondary and primary site allocation using the two lines of evidence. Of particular importance was the recognition that (a) the bodies may have entered primary mass graves with an associated plant and pollen assemblage from an execution site, and (b) that all grave sites are likely to contain both foreign and local fill. It is therefore essential that in the field as much effort as possible is made to differentiate between local matrix and imported body part matrix. The techniques which are increasingly being used in serious criminal investigations in the UK, North America and New Zealand can provide reliable evidence in appropriate circumstances. These are where bodies have been exhumed and where the local geology, soils and/or vegetation are spatially variable enough to provide easily distinguishable non-transient characteristics, particularly pollen and spores and mineralogy. This is believed to be the first time a systematic use of such environmental evidence has been used in a major war crimes investigation. Acknowledgements The author owes a huge gratitude to Richard Wright for his help and encouragement as well as to Jose Pablo Baryabar, Ian Hanson, Dean Manning, Neil Ashcroft and all of the UN ICTY Northeastern Bosnia Exhumation team. Additional thanks must go to Sue Rouillard for the illustrations and to Art Ames for sample preparation. References [1] V.M. Bryant Jr., J.G. Jones, D.C. Mildenhall, Forensic palynology in the United States of America, Palynology 14 (1990) [2] A. Ruffell, J. McKinley, Forensic geoscience: applications of geology, geomorphology and geophysics to criminal investigations, Earth Sci. Rev. 69 (2005) [3] D.C. Mildenhall, Forensic palynology in New Zealand, Palynol. Rev. Palaeobot. 64 (1990) [4] A.G. Brown, A. Smith, O. Elmhurst, The combined use of pollen and soil analyses in a search and subsequent murder investigation, J. Forensic Sci. 47 (2002) [5] R.C. Murray, Forensic geology: yesterday, today and tomorrow, in: K. Pye, D. Croft (Eds.), Forensic Geoscience: Principles, Techniques and Applications, Conference Abstracts, Geological Society of London, 2004, pp [6] M. Horrocks, K.A.J. Walsh, Forensic palynology: assessing the value of the evidence, Rev. Palaeobot. Palynol. 103 (1998) [7] Soil Survey Field Handbook, Soil Survey Technical Monograph No. 5, Harpenden, [8] P.D. Moore, J.A. Webb, M.E. Collinson, Pollen Analysis, Blackwell, Oxford, [9] K.D. Bennett, Annotated catalogue of pollen and pteridophyte spore types of the British Isles, Department of Plant Sciences, University of Cambridge, [10] S.T. Andersen, Identification of wild grass and cereal pollen, Danm. Geol. Unders. Arbog (1978) [11] K. Faegri, P.E. Kaland, K. Krzywinski, Textbook of Pollen Analysis, 4th ed., Wiley, Chichester, [12] H.-J. Beug, Leitfaden der Pollenbestimmung für Mitteleuropa und angrenzende Gebiete, Verlag Dr. Friedrich Pfeil, Munich, [13] R. Andrew, A Practical Pollen Guide to the British Flora, Quaternary Research Association, Technical Guide No. 1, Cambridge, 1984.

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