Trace evidence dynamics of cocaine on banknotes: A comparison study of paper and polymer banknotes

It is well established that a large proportion of paper banknotes in circulation contain traces of cocaine. Being able to discriminate between the innocent transfer of illicit drug particles acquired through everyday interactions with surfaces such as banknotes, as opposed to transfer resulting from criminal activities can provide valuable intelligence that can inform an investigation. With many countries adopting polymer banknotes as legal tender, it is important to consider the transfer of cocaine from these surfaces as well as the retention of these particulates on polymer banknotes for evaluative interpretation in crime reconstruction. This comparison study assessed three contact variables (force, time, and rotation) on the transfer of cocaine particulates from paper and polymer banknotes onto a human skin proxy. The persistence of cocaine particulates was assessed through a realistic scenario which mimicked a cash transaction. Quantifiable amounts of cocaine were transferred onto the human skin proxy across all of the contacts assessed, with a greater transfer observed with contacts involving polymer banknotes and those contacts which involved rotation. Following extensive handling, cocaine persisted on both banknote types, with paper banknotes retaining larger amounts of cocaine than polymer banknotes. These findings show that cocaine can persist on both paper and polymer banknotes for extended periods of time following handling and is therefore available for transfer. This transfer then readily occurs, even when contact is brief and involves relatively small forces. A key distinction between the banknote types was that cocaine particulates are more likely to transfer from polymer banknotes due to the lower retention rate of particulates on this surface. Such insights can aid in evaluating the relevance of illicit drug particles identified on items or persons of interest in crime reconstruction approaches.     

The likelihood approach to compare populations: a study on DNA evidence and pitfalls of intuitions

The paper follows on from earlier work [Taroni F and Aitken CGG. Probabilistic reasoning in the law, Part 1: assessment of probabilities and explanation of the value of DNA evidence. Science & Justice 1998; 38: 165-177]. Different explanations of the value of DNA evidence were presented to students from two schools of forensic science and to members of fifteen laboratories all around the world. The responses were divided into two groups; those which came from a school or laboratory identified as Bayesian and those which came from a school or laboratory identified as non-Bayesian. The paper analyses these responses using a likelihood approach. This approach is more consistent with a Bayesian analysis than one based on a frequentist approach, as was reported by Taroni F and Aitken CGG. [Probabilistic reasoning in the law, Part 1: assessment of probabilities and explanation of the value of DNA evidence] in Science & Justice 1998.     

The transfer of touch DNA from hands to glass, fabric and wood

The transfer of DNA from hands to objects by holding or touching has been examined in the past. The main purpose of this study was to examine the variation in the amount of DNA transferred from hands to glass, fabric and wood. The study involved 300 volunteers (100 for glass, 100 for fabric and 100 for wood) 50% of which were male and 50% female. The volunteers held the material for 60 s. The DNA was recovered from the objects using a minitape lift, quantified using the Quantifiler kit assay, extracted using a ‘Qiagen^® QIAamp DNA mini kit’ and amplified using the AmpFlSTR^® SGM Plus™ Amplification Kit at 28 cycles. The results show that using ANOVA there was a significant difference (F = 8.2, p < 0.05) between the three object types in the amount of DNA recovered. In terms of DNA transfer and recovery, wood gave the best yield, followed by fabric and then glass. The likelihood of success of obtaining a profile indicative of the holder was approximately 9% for glass samples, 23% for fabric and 36% for wood. There was no significant difference between the amount of DNA transferred by male or female volunteers. In this study good shedder status, as defined by obtaining useful profiles of 6 or more alleles, is estimated at approximately 22% of the population. The phenomenon of secondary transfer was observed when mixed DNA profiles were obtained but the incidence was low at approximately 10% of the total number of samples. DNA profiles corresponding to more than one person were found on objects which had been touched by only one volunteer. Although secondary transfer is possible the profiles obtained from touched objects are more likely to be as a result of primary transfer rather than a secondary source.     

The impact of the principles of evidence interpretation on the structure and content of statements

The Forensic Science Service (FSS) has devoted appreciable effort to developing the application of the principles of evidence interpretation. Much of the work has been reported in previous papers in this journal, in particular those that develop a model for Case Assessment and Interpretation (CAI). The principles of interpretation are restated and the implications for structure and content of statements are described.     

Evaluation of preliminary isotopic analysis (13C and 15N) of explosives A likelihood ratio approach to assess the links between semtex samples

Currently, the use of isotopic ratio as corroborative evidence in criminal trials is explored. Beyond the analytical challenges that have been reported elsewhere, the crucial issue of the interpretation of analytical results in a fair and balanced way remains poorly documented. The aim of this paper is to propose a likelihood ratio approach for the evaluation of stable isotope data acquired from semtex samples. It will also lead to recommendations in relation to the acquisition of normalised international data.     

Policing and Crime Act 2017: Changes to pre-charge bail and the impact on digital forensic analysis

Following the enactment of the Police and Crime Act 2017, subsequent amendments to the Police and Criminal Evidence Act 1984 have seen a ‘cap’ placed on the length of time a suspect can be released on bail; a process commonly referred to as ‘police bail’ or ‘pre-charge bail’. Whilst designed to instil consistency and certainty into bail processes to prevent individuals being subject to lengthy periods of regulation and uncertainty, it places additional pressures on forensic services. With a focus on digital forensics, examination of digital media is a complex and time-consuming process, with existing backlogs well documented. The need for timely completion of investigations to adhere to pre-charge bail rules places additional stress on an already stretched service. This comment submission provides an initial analysis of new pre-charge bail regulations, assessing their impact on digital forensic services.     

刑事鉴定制度修改的背景、争议及解读

《刑事诉讼法》在鉴定问题上进行了大幅度地修改,改变了鉴定作为证据种类的名称,删除了"省级人民政府指定的医院"的规定,增加了对鉴定人出庭作证及其人身权利保障等内容,其进步意义应当是肯定的。然而,《刑事诉讼法》有关鉴定修改触及的内容均需要从修改的缘故、争议问题被修改的程度以及执行中可能遇到的障碍等方面予以理论分析与诠释,以便对此问题有一个科学的认识与理解。     

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.     

Electronic evidence: A proposal to reform the presumption of reliability and hearsay

There is a general concern amongst judges, lawyers and legal scholars that evidence in digital format is not to be trusted, given that it can be altered and manipulated with ease. Some jurists have called for a UN Convention on matters relating to the authentication and admissibility of electronic evidence. It is debatable whether such a Convention is necessary, but guidance of an international nature might be welcome, providing that any such guidance remains guidance, and does not ossify into legal requirements that fail to take into account the dynamic and constantly developing changes in information technology. In any event, the accuracy of the presumption in England & Wales that a computer is in order at the material time is highly debatable, and it is suggested that this presumption ought to be reformed.     

A study on the forensic mechanisms of VoIP attacks: Analysis and digital evidence

This paper discusses the use of communication technology to commit crimes, including crime facts and crime techniques. The analysis focuses on the security of voice over Internet protocol (VoIP), a prevention method against VoIP call attack and the attention points for setting up an Internet phone. The importance of digital evidence and digital forensics are emphasised. This paper provides the VoIP digital evidence forensics standard operating procedures (DEFSOP) to help police organisations and establishes an experimental platform to simulate phone calls, hacker attacks and forensic data. Finally, this paper provides a general discussion of a digital evidence strategy that includes VoIP for crime investigators who are interested in digital evidence forensics.     

Journey history reconstruction from the soils and sediments on footwear: An empirical approach

The value of environmental evidence for reconstructing journey histories has significant potential given the high transferability of sediments and the interaction of footwear with the ground. The importance of empirical evidence bases to underpin the collection, analysis, interpretation and presentation of forensic trace materials is increasingly acknowledged. This paper presents two experimental studies designed to address the transfer and persistence of sediments on the soles of footwear in forensically relevant scenarios, by means of quartz grain surface texture analysis, a technique which has been demonstrated to be able to distinguish between samples of mixed provenance.It was identified that there is a consistent trend of transfer and persistence of sediments from hypothetical pre-, syn- and post-crime event locations across the sole of the shoe, with sediments from ‘older’ locations likely to be retained in small proportions. Furthermore, the arch of the shoe (the area of lowest foot pressure distribution) typically (but not exclusively) retained the highest proportion of grain types from previous locations including the crime scene. A lack of chronological layering of the retained sediments was observed indicating that techniques that can identify the components of mixed provenance samples are important for analysing footwear sediment samples. It was also identified that the type of footwear appeared to have an influence on what particles were retained, with high relief soles that incorporate recessed areas being more likely to retain sediments transferred from ‘older’ locations from the journey history. In addition, the inners of footwear were found to retain sediments from multiple locations from the journey history that are less susceptible to differential loss in comparison to the outer sole. These findings provide important data that can form the basis for the effective collection, analysis and interpretation of sediments recovered from both the outer soles and inners of footwear, building on the findings of previously published studies. These data offer insights that enable inferences to be made about mixed source sediments that are identified on footwear in casework, and provide the beginnings of an empirical basis for assessing the significance of such sediment particles for a specific forensic reconstruction.     

Forensic laboratory backlog: The impact of inconclusive results of marijuana analysis and the implication on analytical routine

Forensic laboratories worldwide are struggling to keep up with the increasing number of cases submitted for analysis, regardless of the reasons, backlog of controlled substances cases is a reality in many countries. In this paper we analyse the number of petitioned examinations (from 2016 to 2020) and the data from 11,655 marijuana TLC results from the Forensic Laboratory in the Federal District Civil Police in Brazil. Data demonstrates that backlog increases inconclusive results, with storage and light playing a crucial role in the process. Additionally we explored the repercussions of delayed forensic results for controlled substances and propose an approach to overcome waiting time in this context.     

The impact of CCTV on fundamental rights and crime prevention strategies: The case of the Catalan Control Commission of Video surveillance Devices

Many authors have written about issues related to privacy, legitimacy and efficiency in relation to CCTV systems in public space as a crime prevention strategy. Some have approached them separately; others have tried to come up with more comprehensive approaches. Few, however, have dealt with how such concerns have been put into practice by those who have to decide on the uptake of CCTV. This article considers some reflections on efficacy, legitimacy and privacy in relation to CCTV, as an introduction to the case of how the members of the Control Commission of Video surveillance Devices in Catalonia took these issues into consideration and interpreted the Law when deciding whether to approve a petition submitted by the City Council to install three cameras in Barcelona’s public space in 2003. It concludes by drawing some conclusions from the process, as a way to highlight the complexity of the policy process around surveillance in open, public spaces.     

From crime scene to courtroom: A review of the current bioanalytical evidence workflows used in rape and sexual assault investigations in the United Kingdom

Sexual assault casework requires the collaboration of multiple agency staff to formalise an investigative pipeline running from crime scene to court. While the same could be said of many other forensic investigations, few require the additional support of health care staff and the combined forensic involvement of body-fluid examiners, DNA experts and analytical chemists. The sheer amount of collaborative effort between agencies is laid out through a detailed examination of the investigative workflow from crime scene to courtroom with each step in the pipelines detailed and discussed. Beginning with a review of sexual assault legislation in the United Kingdom this article details how sexual assault investigations are initiated by police and supported by sexual assault referral centre (SARC) staff who are often the first responders providing primary healthcare and patient support to victims while simultaneously collecting and assessing forensic evidence. Detailing the myriad of evidential material that can be documented and collected at the SARC, the review identifies and categorises key forensic tests to first detect and identify body-fluids recovered from evidence through to the secondary analysis of DNA to help identify the suspect. This review also focusses on the collection and analysis of biological material used to support the allegation that the sexual activity was non-consensual and provides a breakdown of common marks and trauma as well as a review of common analytical methods used to infer Drug Facilitated Sexual Assault (DFSA). The culmination of the investigative pipeline is discussed by reviewing the Rape and Serious Sexual Assault (RASSO) workflow used by the Crown Prosecution Service before providing our thoughts on the future of forensic analysis and possible changes to the described workflows.     

The Reconstruction of the Dynamic of a Murder Using 3D Motion Capture and 3D Model Buildings: The Investigation of a Dubious Forensic Case

Photographic surveying is fundamental to crime scene investigation. It is performed using 2D images; however, this method is limited because it does not offer a detailed view. We present a 3D (three‐dimensional) experimental model that has clarified unsolved aspects of a homicide. A woman was found dead in her home. Considering the large number of injuries on the victim, signs of the use of two weapons, and the absence of traces of the killer/s, several hypotheses about the dynamics and the number of offenders were made. The forensic surveys suggested that a single offender had used two weapons at the same time, but this hypothesis was considered to be impossible by investigators. Our 3D model allowed us to experimentally reproduce the murder and compare various dynamics. The model was used as evidence in Court to prove the hypothesis of a single killer and demonstrate that no other people were involved.     

司法鉴定行政与司法视角的边界——民诉证据司法解释鉴定内容的思考

2019年12月26日,最高人民法院发布了《关于修改〈关于民事诉讼证据的若干规定〉的决定》,备受司法界关注。其中,涉及司法鉴定的条款达24条之多,笔者结合《司法鉴定程序通则》,对相关内容予以了梳理与比较,揭示了民事证据规定给司法鉴定带来的变化与问题。民事证据规定重点规制了司法鉴定启动、受理、鉴定人出庭接受质询、鉴定人诚信承诺、鉴定人权利保障,鉴定人的出庭义务、遵守鉴定时限的义务,以及围绕鉴定资料的真实性、合法性方面的规定,以期保障鉴定质量。与此同时,民事证据规定也带来了管理上的边界之争的问题,包括司法鉴定行政管理部门与法院之间、法院与司法鉴定机构之间,以及法官与鉴定人之间权利义务的边界之争与之推,司法鉴定呈现多头管理已见端倪。本研究直面司法鉴定发展中的问题,建议尽早启动司法鉴定立法工作,强化鉴定意见的法庭质证,明确虚假鉴定的认定标准,梳理鉴定多头管理乱象等等,希望可以对司法鉴定制度的改革有所裨益。     

The Application of the Central Limit Theorem and the Law of Large Numbers to Facial Soft Tissue Depths: T‐Table Robustness and Trends since 2008,

By pooling independent study means (), the T‐Tables use the central limit theorem and law of large numbers to average out study‐specific sampling bias and instrument errors and, in turn, triangulate upon human population means (μ). Since their first publication in 2008, new data from >2660 adults have been collected (c.30% of the original sample) making a review of the T‐Table's robustness timely. Updated grand means show that the new data have negligible impact on the previously published statistics: maximum change = 1.7 mm at gonion; and ≤1 mm at 93% of all landmarks measured. This confirms the utility of the 2008 T‐Table as a proxy to soft tissue depth population means and, together with updated sample sizes (8851 individuals at pogonion), earmarks the 2013 T‐Table as the premier mean facial soft tissue depth standard for craniofacial identification casework. The utility of the T‐Table, in comparison with shorths and 75‐shormaxes, is also discussed.