Novel recovery methods for biological materials in cases of alleged sexual assault: A word of caution

Many believe that an increase in the public confidence in the investigation of sexual crimes, and in conviction rates, will lead to an increase in the reporting of these crimes. Consequently, Forensic Science Providers are continually striving to make improvements in evidence recovery and examination and the subsequent interpretation of evidence. One development is in methods that enable an individual to self-sample. However, in cases where a complainant has self-sampled, questions of when the samples were taken, how they were stored and so on, can be legitimately raised. Additionally the continuity and integrity of evidential samples may be questioned resulting in them not being acceptable to the courts and potential evidence could therefore be lost. There is a large emotional and psychological impact of sexual assault and rape and no complainant who reports a sexual assault and recovers material should have that evidence inadmissible to a court. Specialised units for victims of alleged sexual violence are available and offer far more than the recovery of evidential samples. This commentary on behalf of the Faculty of Forensic & Legal Medicine (FFLM) and the Association of Forensic Science Providers Body Fluid Forum (AFSP BFF) highlights the need for after care for the victims of sexual assault and why all evidence recovered in cases of alleged sexual assault and sexual violence should be obtained in line with best practice protocols.     

Autosomal microsatellite allele frequencies for a nationwide dataset from the Australian Caucasian sub-population

DNA profiling results presented in court must be accompanied by a statistical estimate of its evidential weight. In calculating such statistics, allele frequencies from the tested loci are required. This paper reports allele frequencies and the results of population genetic testing of datasets of autosomal microsatellite profiles from Australian Caucasian donors. In contrast to previous practice in Australia these data have been collated at the national level rather than at the State and Territory level. We consider that this national dataset could be used in forensic DNA casework throughout Australia as previously recommended by Ayres et al. [K.L. Ayres, J. Chaseling, D.J. Balding, Implications for DNA identification arising from an analysis of Australian forensic databases, Forensic Sci. Int. 129 (2002) 90-98].     

Development of a searchable major and trace element database for use in forensic soil comparisons

Forensic soil comparisons are normally undertaken on the basis of several physical, chemical and biological properties, but in all cases the interpretation of results is dependent on the availability of relevant contextual information. This paper summarises the results of major and trace element analyses performed using inductively coupled plasma atomic emission spectrometry and inductively coupled plasma-mass spectrometry on the < 150 µm size fraction of 1896 soil samples collected in connection with forensic investigations in England and Wales between 1999 and 2007. A number of new methods are described which facilitate inter-sample comparison. Although the available data do not provide uniform geographical coverage they do provide useful information which can assist police search investigations and they provide valuable contextual information which aids the evidential assessment of soil evidence when used in court. There is considerable scope to improve the database by increasing the geographical coverage and increasing the number of soil attributes which are included.     

New science,old convictions ? Texas Senate Bill 344: identifying further necessary reform in forensic science

In June 2013, Texas Senate Bill 344 (SB 344) was signed into law after strong Innocence Project support. SB 344 has since transformed the Texan judicial landscape. Known as the ‘Junk Science Writ’, SB 344 enables the court to grant habeas corpus relief based on scientific evidence that ‘(1) was not available to be offered by a convicted person at the convicted person''s trial; or (2) contradicts scientific evidence relied on by the state at trial’. Inmates, such as the ‘San Antonio Four’, whose convictions were based upon what is now considered ‘faulty’ medical and forensic testimony, have been released under SB 344. Yet, science, as a field dependent on innovation, is inherently prone to debunking the scientific and forensic methods the law has relied upon to convict individuals. This commentary identifies policy behind SB 344, how SB 344 may influence the perception of science in the courtroom, and how ‘junk science’ is defined and/or limited. Furthermore, this commentary concludes that to achieve justice in the legal system through habeas relief based on ‘junk science’, it is necessary to revitalize and standardize forensic science.     

Application of Raman spectroscopy in forensic investigation of questioned documents involving stamp inks

Stamp pad inks from different manufacturers across India have been analyzed to investigate the feasibility of Raman scattering as a tool for forensic analysis of questioned documents involving stamp inks. Nine different stamping inks were analyzed by both Raman spectroscopic and HPTLC methods. The results demonstrate the effectiveness of these methods in classifying the investigated stamping inks based on their spectral pattern and HPTLC chromatogram. Raman scattering tool was able to determine the sequence of heterogeneous intersection strokes involving a blue stamp pad ink and other writing instruments, such as ballpoint pen ink (red and black), pencil and laser printer toner. However, this method was unable to resolve the exact sequencing for the intersection strokes involving investigated stamp ink and blue ballpoint ink or gel pen ink (all colors).     

Considerations on the ASTM Standards 1789‐04 and 1422‐05 on the Forensic Examination of Ink

Abstract: The ASTM standards on Writing Ink Identification (ASTM 1789‐04) and on Writing Ink Comparison (ASTM 1422‐05) are the most up‐to‐date guidelines that have been published on the forensic analysis of ink. The aim of these documents is to cover most aspects of the forensic analysis of ink evidence, from the analysis of ink samples, the comparison of the analytical profile of these samples (with the aim to differentiate them or not), through to the interpretation of the result of the examination of these samples in a forensic context. Significant evolutions in the technology available to forensic scientists, in the quality assurance requirements brought onto them, and in the understanding of frameworks to interpret forensic evidence have been made in recent years. This article reviews the two standards in the light of these evolutions and proposes some practical improvements in terms of the standardization of the analyses, the comparison of ink samples, and the interpretation of ink examination. Some of these suggestions have already been included in a DHS funded project aimed at creating a digital ink library for the United States Secret Service.     

Use of Bayesian networks in forensic soil casework

Forensic soil comparisons can be of high evidential value in a forensic case, but become complex when multiple methods and factors are considered. Bayesian networks are well suited to support forensic practitioners in complex casework. This study discusses the structure of a Bayesian network, elaborates on the in- and output data and evaluates two examples, one using source level propositions and one using activity level propositions. These examples can be applied as a template to construct a case specific network and can be used to assess sensitivity of the target output to different factors and identify avenues for research.     

Clothing damage analysis and the phenomenon of the false sexual assault

This paper describes three recent false sexual assaults examined at the Victoria Forensic Science Centre laboratory where clothing damage analysis assisted in the resolution of the case. Suspected false reports of sexual assaults are often sensitive cases with little other forensic evidence. Any evidential value that can be obtained is thus valuable in order to minimize any ordeal to the complainant and any suspect and to conserve valuable resources. The findings illustrate the application of clothing damage analysis in a cross section of confirmed false sexual assault reports and the fact that the forensic examiner should be aware of the potential evidential value of this kind of analysis. Furthermore, the corroboration of a victim's scenario when the investigator has doubts may be no less valuable as it may minimize the adversarial ordeal that is often faced by a rape victim.     

Interpretation of repeat measurement DNA evidence allowing for multiple contributors and population substructure

Due to the circumstances in some forensic cases, very small amounts of DNA (<100 pg) may be obtained. This, in turn, may affect the reliability of the PCR process, and so it may be advisable to repeat the amplification process for confirmatory purposes. Gill et al. [Forensic Sci. Int. 112 (2000) 17] proposed a method for the statistical evaluation of the PCR replicate information. In this paper we formalize the method proposed by Gill et al. [Forensic Sci. Int. 112 (2000) 17], and extend it to allow for cases involving mixed stains and for population substructure.     

Identifying the scene of a crime through pollen analysis

The forensic analysis of pollen involves the comparison of crime scene and reference pollen samples. Successful matches are frequently used to solve time- or location-related crimes. Despite its prospects in criminal investigation, forensic palynology is still underused in casework due to inherent shortcomings such as its limited evidential weighting, scarcity of skilled palynologists dedicated to forensic casework and the laborious nature of analytical procedures. To address these challenges, the current state-of-the-art in forensic palynology is transiting from the traditional light microscopic methods that dominated the early days of palynology to more contemporary approaches like Raman spectroscopy, stable isotope analysis and DNA metabarcoding. The major challenges of these methods, however, include a lack of optimisation to forensic expectations and the unavailability of robust databases to permit accurate data interpretation, and quests to resolve these problems constitute the theme of current research. While reiterating the usefulness of pollen analysis in criminal investigation, this report recommends orthogonal testing as a way of improving the evidential weighting of forensic palynology.     

The forensic examination of structural fires in Victoria,Australia: Decision-making processes and impact on judicial outcomes

There is a body of published research that has evaluated the contribution of forensic science to the criminal justice system, but many disciplines of forensic science remain unexplored in this regard. The aim of this study was to examine the contribution that forensic fire examination services provide to criminal investigations and court processes in arson cases. Forensic fire examination services differ in a number of ways to the disciplines covered in previous research on the impact of forensic evidence on justice outcomes. Forensic fire examinations involve a combination of scene examination and laboratory analyses, and the results can provide critical evidence of whether an incident that has occurred is a criminal offence (i.e. whether a fire has occurred as the result of an act of arson). Forensic fire examination is also a discipline that has faced challenges and undergone development in recent decades regarding its scientific basis and the issue of contextual bias. In this study, data were collated for 273 structural fires that were examined by the forensic fire services in Victoria, Australia. In this jurisdiction, scene and laboratory forensic services are delivered within short time frames with a focus on providing impartial scientific and investigative services to assist criminal investigations conducted by police. The current dataset was highly skewed in terms of criminal justice outcomes and was not suitable for conducting the planned statistical analyses. Nonetheless, the pattern of findings obtained suggested that the inclusion of forensic evidence which supported the prosecution of arson may be associated with an increased likelihood of suspects being charged and defendants found guilty. Examination of the decision-making process of the forensic fire examiners has provided insight into the variety of evidence that is considered by forensic experts in reaching the important conclusion about the origin and cause of structural fires.     

近十年来我国现代法医昆虫学研究进展

法医昆虫学(Forensic entomology)指的是应用昆虫学知识解决法律上问题的法医学分支学科,在死后间隔时间判断,特别是腐败尸体的死后间隔时间判断等方面有著无可比拟的优越性。本文讨论了法医昆虫学的研究领域,从理论研究与实践应用两方面概述了近十年来法医昆虫学在我国的进展。     

The importance of dark adaptation for forensic examinations; an evaluation of the Crime-lite Eye™

Forensic practitioners are recommended to dark adapt their eyes prior to conducting evidential searches in the dark. The dark adaptation process remains poorly standardised across the discipline, with little quantified regarding the benefits of such preparative steps. Herein, we report the findings of a study that recruited 50 participants to assess the effectiveness of the Crime-lite Eye?, a darkness adaptation device developed to assist forensic practitioners both in the laboratory and in field. Participants were tasked with searching for the fluorescent signatures left by reaction of 1,8-diazafluoren-9-one (DFO) with amino acids, in a manner akin to the fluorogenic fingerprint treatment of porous evidence. Using an Epson Stylus Photo R265 inkjet printer, ink cartridges were filled with alanine solutions of various concentrations, allowing different motifs to be printed onto copy paper and subsequently developed using DFO. Participants searched for this ‘evidence’ both with and without dark adapted vision. On average, participants were able to locate and correctly recognise 16% more evidence once dark adapted using the Crime-lite Eye?.The increase in evidence located by participants once dark adapted suggests that crime scene officers should be dark adapting in order to visualise as much as possible. The time taken to dark adapt, 10?min on average during this study, is not excessively long, and should not significantly slow the investigation.     

基于Citespace的法医临床学研究发展历程分析

目的运用Citespace软件对法医临床学相关文献绘制知识图谱、进行可视化分析,探究该学科领域研究热点和动态发展,梳理鉴定难点脉络。方法汇总CNKI收录《中国法医学杂志》《刑事技术》《法医学杂志》《中国司法鉴定》刊登的法医临床学相关论文,利用Citespace分析其关键词、研究热点、基金资助、作者、发文机构及所在地等。结果法医临床学作为法医学分支学科之一,近年来呈现的科研成果部分获基金资助,多由开设法医学专业的院校完成;随着科研理论、技术方法推陈出新,法医临床学鉴定标准、版本也得以构建、更迭、完善,鉴定体量位居法医"四大类"之首。结论作为最具中国特色的法医学分支学科,法医临床学研究着重服务司法实践、以期用成果技术反哺鉴定,实现学术、实践的交流、转化。通过Citespace知识图谱可视化分析学科发展历程,有助于回溯此间规律,提示未来研究方向,提升鉴定业务水平,为持续增强法医临床学学科影响力提供借鉴。     

Application of the Electrical Network Frequency (ENF) Criterion. A case of a digital recording

One of the new methods of investigating the authenticity of evidential digital audio recordings uses the Electrical Network Frequency (ENF) Criterion. It is based on analysing the signal corresponding to the fundamental frequency of the current in the electrical network, which is present in a recording and comparing it with appropriate, reliable reference. Studies carried out at the Institute of Forensic Research in Cracow were aimed at validating this method, that is, assessing its usefulness in forensic examinations of evidential digital recordings in Poland. These studies enabled us to develop and implement a procedure for using the ENF Criterion method to assess the integrity of digital recordings and to establish when these recordings were made.     

The routine use of C-reactive protein in forensic investigations

In clinical medicine, C-reactive protein (CRP) is extensively used as a general marker for immune system activation, and post-mortem applicability has been established [M.Q. Fujita, B.L. Zhu, K. Ishida, L. Quan, S. Oritani, H. Maeda, Serum C-reactive protein levels in postmortem blood-an analysis with special reference to the cause of death and survival time, Forensic Sci. Int. 130 (2002) 160-166; L. Uhlin-Hansen, C-reactive protein (CRP), a comparison of pre- and post-mortem blood levels, Forensic Sci. Int. 124 (2001) 32-35]. We have analysed the routine use of CRP in non-selected cases. Scarcity of blood available for analysis is a common problem in forensic investigation, and in response to this we have developed a method using liver as a source. In 50 consecutive autopsy cases, we have evaluated method, validated results and discussed their interpretation. In three cases the analysis was not possible. For each of the remaining cases (n=47) we have analysed whole blood, serum and/or liver samples. 57% (n=25) had serum CRP > 10 mg/L. Serum levels were higher than in whole blood or liver. CRP levels in serum and whole blood samples were stable in more than one month after death, making storage for later analysis possible. Liver levels peaked at one week, but after one month putrefaction was obvious. CRP levels were independent of the post-mortem interval. The use of liver as a source has not yet been described in literature. Our results in liver samples correlate well with plasma results, and liver is a good post-mortem alternative when blood is not available. We conclude that CRP measurements are easy, viable and inexpensive in a forensic setting, and that the number of cases with CRP elevation is high in a non-selected forensic material. In cases of doubt, marked elevation of CRP is an indicator of natural mode of death, and in cases of trauma, it indicates vital reaction. It can be used as a pre-autopsy screening, leading to a more extensive search for diseases not easily diagnosed, such as sepsis or ketoacidosis.     

“I couldn't find it your honour,it mustn't be there!” – Tool errors,tool limitations and user error in digital forensics

The field of digital forensics maintains significant reliance on the software it uses to acquire and investigate forms of digital evidence. Without these tools, analysis of digital devices would often not be possible. Despite such levels of reliance, techniques for validating digital forensic software are sparse and research is limited in both volume and depth. As practitioners pursue the goal of producing robust evidence, they face the onerous task of both ensuring the accuracy of their tools and, their effective use. Whilst tool errors provide one issue, establishing a tool's limitations also provides an investigatory challenge leading the potential for practitioner user-error and ultimately a grey area of accountability. This article debates the problems surrounding digital forensic tool usage, evidential reliability and validation.     

Identifying and measuring juror pre-trial bias for forensic evidence: development and validation of the Forensic Evidence Evaluation Bias Scale

Abstract

Previous research has provided support for the impact of juror pre-trial bias on judicial decision making, particularly in cases where the evidence presented at trial is of weak or ambiguous probative value. In an effort to identify whether a pre-trial bias for forensic evidence exists, the Forensic Evidence Evaluation Bias Scale (FEEBS) was developed and tested. The results of a principal components analysis suggested that two distinct constructs were being measured, corresponding to a pro-prosecution and pro-defence bias toward forensic evidence. In a second validation study, scores on these two subscales were compared with other existing juror bias measures (Juror Bias Scale and Belief in a Just World) and in a mock juror decision making task only the pro-prosecution subscale of the FEEBS predicted the perceived strength of forensic evidence. A partial mediation model is presented which explains the relationship between this bias and verdict preferences. The implications of this potential juror bias are discussed in the context of real juries, the CSI Effect (which refers to anecdotal claims that jurors are biased by the popularity of fictional representations of forensic science on television) and peremptory challenges, as well as future research directions.     

The cannabinoid content of marihuana samples seized in Greece and its forensic application

The three major cannabinoids, Δ⁹-tetrahydrocannabinol (Δ⁹-THC), cannabidiol (CBD) and cannabinol (CBN) were identified and determined quantitatively using a GCD (GC–EI) instrument, in samples of illicit herbal cannabis, seized by Customs and Police authorities in two areas of Greece (Ipiros and Lakonia) during 1996. These samples were sent by the above authorities to the Department of Forensic Medicine and Toxicology, University of Athens, for forensic chemical analysis. The cannabinoid content of these samples led to the classification of cannabis into two chemical phenotypes and to the differentiation of resinous and textile plants by using three different classification indexes. The cannabinoid content of cannabis plants is of forensic value in determining the geographical origin of cannabis samples, since it can be used for their classification, allocating this way the area of cultivation of the relative plants. The forensic aspects of cannabis classification are discussed.     

Freshwater diatom transfer to clothing: Spatial and temporal influences on trace evidence in forensic reconstructions

Environmental indicators are increasingly sought and analysed in a range of forensic reconstructions. Although the majority of casework and research studies are concerned with the criminal investigation of terrestrial habitats (soils, sediments, plants etc.), freshwater environments are also frequently encountered as crime scenes. As such, microalgae, particularly diatoms, may provide useful circumstantial trace evidence following their transfer to a victim or perpetrator. Diatom analysis is a relatively underused technique in forensic ecology, although an increased empirical research focus is beginning to recognise the evidential value of a transferred assemblage. This study aimed to examine three of the spatial and temporal variables known to influence the extent of an initial transfer of trace particulates, within the context of freshwater diatoms to clothing. A series of experiments were designed to consider the impact of recipient surface characteristics (clothing type), source environment conditions (seasonality), and morphological (type of diatom) variability, on the total number (no. per cm²) and species richness (total no. sp.) of an evidential diatom sample recovered from clothing. Nine commonly used clothing materials were immersed in a freshwater river at three times of year – the early and late spring and in the winter. Diatoms were recovered using a H₂O₂ extraction technique and examined microscopically. The results demonstrated that diatom transfer to clothing varies significantly, with a greater abundance and a higher species richness transferred to coarse woven surfaces including acrylic, linen, and viscose. Significantly fewer diatoms were transferred to clothing in the winter, in line with seasonal fluctuations in the source environment diatom community. Furthermore, variation in the relative abundance of particular diatom species was identified between clothing types, provisionally suggesting that morphological characteristics may also support or limit the transfer of material. These findings highlight that, although clothing may offer a valuable repository of freshwater diatom trace evidence, the interpretation of evidential material should be approached within an exclusionary framework. Thus, empirical data has been generated to develop evidence bases within forensic ecology, demonstrating some of the spatial and temporal factors which may contribute to or limit the transfer of evidence.