Centre for Australian Forensic Soil Science Guidelines for Conducting Criminal and Environmental Soil Forensic Investigations: Version 10.1 R.W. Fitzpatrick and M.D. Raven Centre for Australian Forensic Soil Science (CAFSS) Client Report: CAFSS_076 (Version 10.1) st 1 February, 2016 Copyright and Disclaimer © 2016 CSIRO. To the extent permitted by law, all rights are reserved and no part of this publication covered by copyright may be reproduced or copied in any form or by any means except with the written permission of CSIRO Land and Water Flagship. Important Disclaimer: CSIRO Land and Water advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO Land and Water Flagship (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. Report Title: Guidelines for Conducting Criminal and Environmental Soil Forensic Investigations: Version 10.1 Authors: R.W. Fitzpatrick and M.D. Raven Affiliations: Centre for Australian Forensic Soil Science Client Report: CAFSS_076 (Version 10.1) 1st February, 2016 Cover Photographs: From left to right photographs of: (a) top of rubber shoe sole with tooth-like edge moulding showing brown (7.5YR4/4 moist) clayey soil (Questioned soil), (b) brown (7.5YR4/4 moist) clayey soil in wooded area at crime scene (Control soil), (c) reddish brown clayey soil with white quartz and dolomite gravel (Reference soil) from road-verge at victim’s house (from Fitzpatrick and Raven, 2009; Fitzpatrick et al. 2012) Executive Summary The experience gained from conducting over 155 case studies, together with research by the Centre for Australian Forensic Soil Science (CAFSS) has led to the development of “broad guidelines for conducting criminal and environmental soil forensic investigations”. This guideline document has been produced to update the earlier publications, which has incorporated information from case investigations conducted by CAFSS. The Guidelines were developed and designed to provide: (i) basic background information on the use of soils and geological materials to discriminate between soil samples from different locations (ii) a systematic approach to examining soils for forensic comparisons and (iii) appropriate methods, which are standardized, inexpensive, accurate and applicable to sampling and characterising small and large samples. The Guidelines are not intended as an authoritative scene of crime manual or laboratory methods manual, but rather as a source of information of approaches in which forensic examinations of soils and related geological materials can be applied to crime investigations, terrorist casework and where environmental incidents occurred. The aim of this guideline document is to provide the basic rationale and define a set of data requirements that will be used by staff in CAFSS to conduct soil forensic investigations. The forensic investigation of soil usually involves the following two main activities: (1) Soil collection and sampling of one or more locations. (2) Soil characterization and evaluation. Of paramount importance in both activities, is continuity of evidence or the chain-of- custody, which must be maintained and documented at all times throughout the entire investigation. Consequently, all sampling methods, sample storage security, soil characterization and analytical methods must be subject to the most rigorous procedures of sample/data handling available so they can be discoverable and questioned in court. Soil collection and sampling of one or more locations Samples are categorised in two ways: 1. Questioned soil samples whose origin is unknown or disputed - often from a suspect or victim and 2. Known soil samples that are grouped into the following three groups of origin in association with the matter under investigation: (i) control soil samples whose origin is known - often from locations such as the crime scene, (ii) Reference soil samples whose origin or type is known and may comprise: (a) type samples held in a museum or soil/geological archive collection, (b) samples collected from known sites linked to a victim or (c) sites/areas from soil or geological maps that can be used to assist in making soil comparisons; (iii) Alibi soil samples are those of known origin - often from locations suggested by a suspect or linked to a suspect (e.g. backyards or driveways at the suspect’s home). Alibi and reference samples provide a measure of the uniqueness of the questioned and control samples hence providing a more comprehensive analysis of the targeted comparator samples to provide a more accurate picture of the within-site heterogeneity. CAFSS Guidelines for conducting criminal and environmental soil forensic investigations (V10) Page 1 Forensic soil comparisons of a questioned sample with one or more samples of known origin are usually based on several pedological, physical, mineralogical and biological properties to evaluate the significance of observed similarities and differences in order to arrive at a conclusion regarding a possible association. Soil can be used to indicate or compare provenance, and therefore be used as intelligence and subsequently evidence to narrow areas of search during an investigation. Evaluative comparison of soil on one article of evidence compared to another, or compared to a known location, can and has been used as evidence in courts of law. Soil characterization and evaluation Soil characterization requires a multidisciplinary approach, which combines descriptive, analytical, and spatial information (e.g. mapping). This approach involves subdividing approaches and methods into the following 4-stages each comprising several steps and involving a combination of techniques: 1. Initial characterization for screening of samples, which involves morphological characterisation of bulk or whole soil samples. 2. Semi-detailed characterization, which involves identification, semi- detailed characterisation and semi-quantification of minerals and organic matter in bulk and on individual soil particles following sample selection and size fractionation (< 50 µm or 100 µm). 3. Detailed characterization, which involves using additional analytical techniques and/or methods of sample preparation, separation or concentration (e.g. size or magnetic or heavy mineral fractionation) to characterise and quantify minerals and organic matter in bulk and on individual soil particles. 4. Integration and extrapolation of soil information from one scale to next. This final stage involves building coherent soil-landscape models of information from microscopic observations to the landscape scale, which may involve soil classification and use of soil, geological and vegetation maps; terrain analysis, remote sensing and geophysics. The progression of a soil forensic examination through each of the four stages will depend on a number of factors such as the amount of sample available and the results from the early stages of the examination. The broad guidelines describe best practice for field (collecting, identifying and describing soil samples) and key laboratory techniques, which requires consistent and correct use of terms and standard methods. This approach has enabled soil properties to be successfully used to discriminate between or compare soils for critical evidence to solve overwhelmingly complex criminal and environmental forensic cases. The guidelines are incorporated in all case investigations conducted by CAFSS. These investigations have included several homicide cases that have been presented before several Supreme Courts in Australia. CAFSS Guidelines for conducting criminal and environmental soil forensic investigations (V10) Page 2 Table of Contents Executive Summary ........................................................................................................ 1 1 Introduction ....................................................................................................... 4 2 Soil sample collection ....................................................................................... 4 3 Questioned soil sample collection ................................................................. 11 4 Known soil sample collection ......................................................................... 13 5 Soil sample chain-of-custody and quarantine approval ............................... 16 6 Characterization Methods and Evaluation ..................................................... 16 6.1 Stage 1: Initial characterization for screening of samples .......................... 19 6.2 Stage 2: Semi-detailed characterization ....................................................... 20 6.3 Stage 3: Detailed characterization ................................................................. 22 6.4 Stage 4: Integration and extrapolation of soil information from one scale to next ............................................................................................ 24 7 Case Assessment and Interpretation ............................................................