Mapping the lateral extent of human cadaver decomposition with soil chemistry

Soil below decomposing cadavers may have a different lateral spatial extent depending upon whether scavengers have access to the human cadaver or not. We examined the lateral spatial extent of decomposition products to a depth of 7cm of soils beneath two decomposing corpses, one in which the subject was autopsied, unclothed and placed under a wire cage to restrict scavenger access and one in which the subject was not autopsied, unclothed and exposed to scavengers. The two bodies had accumulated degree days (ADD) of 5799 and 5469 and post mortem interval (PMI) of 288 and 248d, respectively. The spatial extent for dissolved organic carbon (DOC) and organic nitrogen (DON) for both bodies was large but similar suggesting some movement off site for both compounds. Mean DOC was 1087±727 and 1484±1236μgg(-1) dry soil under the two corpses relative to 150±68μgg(-1) in upslope control soils. Sulfate tended to have 'hot spots' of lower values relative to the control soils indicative of anaerobic respiration. pH was lower and electrical conductivity was higher in the soil under both decomposing cadavers relative to control soils. Some of the nutrients examined downslope of the human remains were significantly higher than control soils upslope suggesting movement of decomposition products off-site which could be an important factor when using human remains detector dogs.     

Particle size analysis of soils under simulated scene of crime conditions: the interest of multivariate analyses

Two simulated scenes of crime have been studied. Soil traces adhering to boots, sport shoes and tissues have been compared with control samples using particle size analysis. Comparisons of percentage of particles per class interval and multivariate analyses were used to determine how the size distribution of each suspect sample varied compared to the original distribution. A loss of coarse fractions characterized most of the suspect samples even though they were derived from soils having different distributional patterns. However, the differences between control and suspect samples were found to be more important for soils dominated by extreme size classes than for soils rich in medium size particles. The differences among soil samples from the same source were found to be restricted to the extreme size classes. The finding of significant differences within size classes ranging from 1 to 0.063 mm should be then considered as a dissimilarity sign between trace sample and hypothetic control soil.     

Particle size analysis of soils under simulated scene of crime conditions: the interest of multivariate analyses

Two simulated scenes of crime have been studied. Soil traces adhering to boots, sport shoes and tissues have been compared with control samples using particle size analysis. Comparisons of percentage of particles per class interval and multivariate analyses were used to determine how the size distribution of each suspect sample varied compared to the original distribution. A loss of coarse fractions characterized most of the suspect samples even though they were derived from soils having different distributional patterns. However, the differences between control and suspect samples were found to be more important for soils dominated by extreme size classes than for soils rich in medium size particles. The differences among soil samples from the same source were found to be restricted to the extreme size classes. The finding of significant differences within size classes ranging from 1 to 0.063 mm should be then considered as a dissimilarity sign between trace sample and hypothetic control soil.     

The evaluation of methods for soil analysis under simulated scenes of crime conditions

Five simulated scenes of crime have been studied in which the soils adhering to shoes, car tyres and plant roots have been compared with multiple control samples using dry colour, ashed colour, pH, saccharide levels and particle size analysis. Colour and pH were found to be as reproducible under simulated scenes of crime conditions as for true duplicates from homogeneous soil, whereas the variation in saccharide levels was slightly greater than for true duplicates. The interpretational scheme developed for the silt and sand fractions of homogeneous soils was applied to the samples from each simulated scene of crime and every comparison was found to be similar at the 99% confidence limit.     

Discrimination of Soils at Regional and Local Levels Using Bacterial and Fungal T‐RFLP Profiling*

Abstract: DNA profiling of microbial communities has been proposed as a tool for forensic comparison of soils, but its potential to discriminate between soils from similar land use and/or geographic location has been largely unexplored. We tested the ability of terminal restriction fragment length polymorphism (T‐RFLP) to discriminate between soils from 10 sites within the Greater Wellington region, New Zealand, based on their bacterial and fungal DNA profiles. Significant differences in bacterial and fungal communities between soils collected from all but one pair of sites were demonstrated. In some instances, specific terminal restriction fragments were associated with particular sites. Patch discrimination was evident within several sites, which could prove useful for site‐specific matching (e.g., matching shoe/car tire print to an object). These results support the need for further understanding of the spatial distribution of soil microbial communities before DNA profiling of soil microbial communities can be applied to the forensic context.     

Lipidic compounds found in soils surrounding human decomposing bodies and its use in forensic investigations – A narrative review

Following decomposition of a human body, a variety of decomposition products, such as lipids, are released into the surrounding environment, e.g. soils. The long-lasting preservation in soils and their high diagnostic potential have been neglected in forensic research. Furthermore, little is known about the preservation, chemical transformation, or degradation of those human derived lipids in soils. To date, several studies identified various lipids such as long-chain free fatty acids and steroids in soils that contained decomposition fluids. Those lipids are preserved in soils over time and could serve as markers of human decomposition in forensic investigations, e.g. for estimating the post-mortem interval or identifying the burial location of a human body. Therefore, this review focuses on the current literature regarding fatty acid and steroid that have been detected in soils and associated with human body decomposition. After a short introduction about human decomposition processes, this review summarises fatty acid and steroid analysis applied in current case studies and studies related to taphonomic research. This review provides an overview of the available studies that have used fatty acids and steroids as identifiers of human decomposition fluid in soils in a forensic context and discusses the potential for developing this innovative field of research with direct application in a forensic context.     

The role of forensic geoscience in wildlife crime detection

The increase in both automation and precision in the analysis of geological materials has had significant impact upon forensic investigations in the last 10 years. There is however, a fundamental philosophical difference between forensic and geological enquiry. This paper presents the results of forensic geoscientific investigations of three cases of wildlife crime. Two cases involve the analysis of soils recovered after incidents of illegal badger baiting in the United Kingdom. The third case involves the illegal importation of Eleonora's Falcon (Falco eleonorae) into the United Kingdom from the Mediterranean. All three cases utilise the analysis of soils by a variety of physical, chemical and biological techniques. These involve mineral and grain size analyses, cation and anion compositions, pH, organic content and pollen analysis. The independent analysis undertaken by specialists in each of these three main fields conclude firstly, that there is a significant similarity between sediments taken at the crime site at both badger setts and with sediments recovered from various spades, shovels and clothing belonging to suspects and secondly, that the soils analysed associated with the removal of the falcon eggs in the Mediterranean contained characteristics similar in many respects to the soils of the breeding areas of F. eleonorae on the cliffs of Mallorca. The use of these independent techniques in wildlife crime detection has great potential given the ubiquitous nature of soils and sediments found in association with wildlife sites.     

High‐throughput Sequencing of Trace Quantities of Soil Provides Reproducible and Discriminative Fungal DNA Profiles

High‐throughput sequencing (HTS) offers improved resolution between forensic soil samples by characterizing individual taxa present; however, the heterogeneous distribution of taxa in soils, and limited quantity of material available, may hinder the reliability of HTS in casework. Using HTS of the internal transcribed spacer, we examined the effect of soil mass (50, 150, and 250 mg) on fungal DNA profiles, focusing on reproducibility and discriminatory power between close proximity soils, and samples with similar textural classification. The results show that reduced soil mass had no significant effect on sample differentiation and that 150 mg soil provides the most reproducible DNA profiles across different soil types. In addition, Ascomycota was identified as a robust fungal target for forensic intelligence as this phylum was detected consistently across all samples regardless of sample quantity. Overall, this study highlights the value of trace quantities of soil for use in forensic casework.     

Bacterial Profiling of Soil Using Genus‐Specific Markers and Multidimensional Scaling*

Abstract: Forensic identification of soil based on microbial DNA fingerprinting has met with mixed success, with research efforts rarely considering temporal variability or local heterogeneity in soil’s microbial makeup. In the research presented, the nitrogen fixing bacteria rhizobia were specifically examined. Soils were collected monthly from five habitats for 1 year, and quarterly in each cardinal direction from the main collection site. When all habitats were compared simultaneously using Terminal Restriction Fragment Length Polymorphism analysis of the rhizobial recA gene and multidimensional scaling, only two were differentiated over a year’s time, however pairwise comparisons allowed four of five soils to be effectively differentiated. Adding in 10‐foot distant soils as “questioned” samples correctly grouped them in 40–70% of cases, depending on restriction enzyme used. The results indicate that the technique has potential for forensic soil identification, although extensive anthropogenic manipulation of a soil makes such identification much more tentative.     

福州市5类山地土的区分方法研究

目的建立一种有效区分地方土壤的方法。方法用能谱仪测试福州市几类山地土的元素成份,用乙酸乙酯/环己烷（1∶1）溶液提取土壤有机质,用凝胶渗透色谱仪分离其有机质成份,用气相色谱—质谱联用仪测试土壤所含低沸点有机质成份。结果根据土壤中元素成份和低沸点有机质成份的差异,以及土壤有机质的凝胶渗透色谱图中主峰数目、主峰保留时间和峰形的差异,可有效区分福州市五类山地土（于山土、屏山土、森林公园土、乌山土和鼓山土）。结论该方法准确可靠、简单易行,具有良好重现性,是一种有效区分土壤的方法。     

Bacterial Profiling of Soil For Forensic Investigations: Consideration of Ex Situ Changes in Questioned and Known Soil Samples

Soil, being diverse and ubiquitous, can potentially link a suspect or victim to a crime scene. Recently scientists have examined the microbial makeup of soil for determining its origin, and differentiating soil samples is well-established. However, when soil is transferred to evidence its microbial makeup may change over time, leading to false exclusions. In this research, “known” soils from diverse habitats were stored under controlled conditions, while evidence soils were aged on mock evidence. Limited quantities of soil were also assayed. Bacterial profiles were produced using next-generation sequencing of the 16S rRNA gene. Overall, known soils stored open at room temperature were more similar to evidence soils over time than were known soils stored bagged and/or frozen. Evidence soils, even as little as 1 mg, associated with the correct habitat 99% of the time, accentuating the importance of considering ex situ microbial changes in soil for its successful use as forensic evidence.     

The effect of soil type on adipocere formation

Adipocere refers to a postmortem product which forms from body fat in the later stages of decomposition. Factors present in the surrounding decomposition environment will influence adipocere formation and may accelerate or retard the process of conversion. One such factor important in burial environments is the type of grave soil in which the burial has taken place. This study was conducted to investigate the influence of various soil types on the formation of adipocere in grave soils. X-ray diffraction and particle size analysis were used to characterise the soils which were essentially chosen on the basis of grain size. Infrared spectroscopy, inductively coupled plasma-mass spectrometry, and gas chromatography-mass spectrometry were used to investigate the lipid profile and chemical composition of adipocere developed from decomposing tissue. The results suggest that adipocere is able to form in various soil types and that particular soil environments may accelerate its formation.     

Elemental analysis of soil samples for forensic purposes by inductively coupled plasma spectrometry--precision considerations

Major and trace elemental composition provides a powerful basis for forensic comparison of soils, sediments and rocks. However, it is important that the potential 'errors' associated with the procedures are fully understood and quantified, and that standard protocols are applied for sample preparation and analysis. This paper describes such a standard procedure and reports results both for instrumental measurement precision (repeatability) and overall 'method' precision (reproducibility). Results obtained both for certified reference materials and example soils show that the instrumental measurement precision (defined by the coefficient of variation, CV) for most elements is better than 2-3%. When different solutions were prepared from the same sample powder, and from different sub-sample powders prepared from the same parent sample, the CV increased to c. 5-6% for many elements. The largest variation was found in results for certified reference materials generated from 23 instrument runs over an 18 month period (mean CV=c. 11%). Some elements were more variable than others. W was found to be the most variable and the elements V, Cr, Co, Cu, Ni and Pb also showed higher than average variability. SiO2, CaO, Al2O3 and Fe2O3, Rb, Sr, La, Ce, Nd and Sm generally showed lower than average variability, and therefore provided the most reliable basis for inter-sample comparison. It is recommended that, whenever possible, samples relating to the same investigation should be analysed in the same sample run, or at least sequential runs.     

Effect of blood stained soils and time period on DNA and allele drop out using Promega 16 Powerplex kit

Blood stained soils may be of great interest in forensic incidents. Amplification of DNA from soil is often inhibited by co-purified contaminants. Different soils types from Pakistan and Turkey were stained with blood and samples were collected systematically after specified intervals. Rapid, inexpensive, large-scale DNA extraction method involving minimal purification was developed. DNA was quantized using Spectrophotometer and Fluorometer and was confirmed by Agarose Gel Electrophoresis. DNA extracted from different soils in different periods showed a remarkable decrease in yield as well as degradation in every extraction. PCR amplification was performed using various DNA targets present in Promega 16 Powerplex^® System kit. Amplification could not carry out in all loci especially in degraded samples taken after 20 days. Allele n locus drop out was noticed which shows that DNA was degraded. For some loci more than 2 alleles were also noticed showing contamination while working with the blood stained soils.     

Hair analysis for driving licence in cocaine and heroin users. An epidemiological study

Diagnosis of drug exposure is strongly supported by analysis of hair samples. In the province of Brescia, Italy, for regranting driving license to drug addicts or occasional abusers, a control programme was adopted including analysis of illicit drugs in two hair segments (0-3 and 3-6 cm) and in urine. From January 1998 to April 1999, upon request of the Local Medical Commission, 697 hair samples were tested in our laboratory. One hundred and eighty subjects resulted positive in hair for one or two of the controlled drug classes (73.3% for cocaine, 10% for opiates, 16.7% for both). Positive subjects were classified by residence, age, sex and license category. Seventy-two subjects were called back after 6-12 months and submitted to a second hair and urine analysis: in 34 cases the result of the first analysis was confirmed (19 negatives, 15 positives for one or both drug classes). Another 37 cases tested positive at the first control and negative at the second, suggesting the hypothesis that a strict control may have a significant deterrent function. The high percentage of negative results at the second control may be explained by the prevalence of cocaine users in the examined population. Our results allow us to conclude that the strict application of control rules lead to a decrease of social risk behaviours.     

Time Radically Alters Ex Situ Evidentiary Soil 16S Bacterial Profiles Produced Via Next‐Generation Sequencing,,

Previous research has revealed the potential of soil bacterial profiling for forensic purposes; however, investigators have not thoroughly examined fluctuations in microbial profiles from soil aged on evidence. In this research, soils collected from multiple habitats were placed on evidence items and sampled over time, and then bacterial profiles were generated via next‐generation sequencing of the 16S rRNA locus. Bacterial abundance charts and nonmetric multidimensional scaling plots provided visual representation of bacterial profiles temporally, while supervised classification was used to statistically associate evidence to a source. The ex situ evidence soils displayed specific, consistent taxonomic changes as they aged, resulting in their drift in multidimensional space, but never toward a different habitat. Ninety‐five percent of the 364 evidentiary profiles statistically classified to the correct habitat, with misclassification generally stemming from evidence type and increased age. Ultimately, understanding bacterial changes that occur temporally in ex situ soils should enhance their use in forensic investigations.     

Chemical enhancement of soil based footwear impressions on fabric

This study investigates the enhancement of footwear impressions prepared with soils from different locations on a variety of fabric surfaces with different morphology. Preliminary experiments using seventeen techniques were carried out and the best responding reagents were evaluated further. Results indicated that the soils investigated (a cross-section of soils from Scotland) are more likely to respond to reagents that target iron ions rather than calcium, aluminium or phosphorus ions. Furthermore, the concentration of iron and soil pH did not appear to have an effect on the performance of the enhancement techniques. For the techniques tested, colour enhancement was observed on all light coloured substrates while enhancement on dark coloured fabrics, denim and leatherette was limited due to poor contrast with the background. Of the chemical enhancement reagents tested, 2,2'-dipyridil was a suitable replacement for the more common enhancement technique using potassium thiocyanate. The main advantages are the use of less toxic and flammable solvents and improved clarity and sharpness of the enhanced impression. The surface morphology of the fabrics did not have a significant effect on the enhancement ability of the reagents apart from a slight tendency for diffusion to occur on less porous fabrics such as polyester and nylon/lycra blends.     

Post-release controls for sex offenders in the U.S. and UK

In recent years, both the United States and United Kingdom have developed numerous innovations in legal efforts to protect society from sex offenders. Each country has adopted special provisions for sex offenders. In particular, governments have focused on forms of social control after release from incarceration and probation. These policy innovations for this category of offenders have been more far reaching than those for any other offender population. The two jurisdictions have adopted policies with similar goals, but the selected strategies have important differences. Generally speaking, the U.S. has favored an ever-expanding set of policies that place sex offenders into broad categories, with few opportunities that distinguish the appropriate responses for individual offenders. The UK government observed the proliferation of Megan's Laws¹ in the U.S., and deliberately chose to establish carefully controlled releases of information, primarily relying on governmental agencies to work in multi-disciplinary groups and make case-specific decisions about individual offenders. Although the UK policy leaders expressed significant concern that the public's response to knowing about identified sex offenders living in the community would result in vigilantism, to date the results have not borne out this fear. Both governments have turned to other crime control measures such as polygraphy testing, electronic monitoring, and civil protection orders as a means to prevent further sexual violence.     

In- and out-flows of elements in bones embedded in reference soils

Possible exchanges of elements between bone and the surrounding soil after being embedded underground for 2 years were estimated. Bone pieces were samples from human vertebrae without any treatments after resection. Sixteen elements were determined by atomic emission mass spectrometry. These were divided into three types; Type I, an in-flow in which elements increased, as in Fe, Al and Ba; type II, a balanced decrease in which changes were found in S, Mg and Zn; and type III, an out-flow in which elements, such as Ca and P, entered into bones from embedded soils. These exchanges depended on the varying nature of soils and also on the time underground. The exchanges were progressed in duration of the time after burial. Data obtained are possible references to judge the time-lapse after burial of bones in relating to characters of soils embedded, and to identify proper bone elements from containment elements.