The influence of forensic evidence on the case outcomes of homicide incidents

Objective

In spite of the growth of forensic science services little published research exists related to the impact of forensic evidence on criminal case outcomes. The present study focused on the influence of forensic evidence on the case processing of homicide incidents.

Materials and Methods

The study utilized a prospective analysis of official record data that followed homicide cases in five jurisdictions from the time of police incident report to final criminal disposition.

Results

The results showed that most homicides went unsolved (34.5% conviction rate). Only 55.5% of the 400 homicide incidents resulted in arrest of which 77% were referred to the district attorney. On the other hand, 94% of cases referred to the district attorney were charged. Cases were more likely to have arrests, referrals, and charges when witnesses provided information to the police. Suspects who knew their victims were more likely to be arrested and referred to the district attorney. Homicides committed with firearms were less likely to be cleared. The most noteworthy finding was that none of the forensic evidence variables significantly influenced criminal justice outcomes.

Conclusions

The study results suggest that forensic evidence is auxiliary and non-determinative for homicide cases.     

Scent identification evidence in jurisdiction (drawing on the example of judicial practice in Poland)

One of the most significant challenges for contemporary forensic science seems to be research of new sources of physical evidence. Particularly after successful implementation of revolutionary DNA identification law enforcement agencies look for other new and perhaps more efficient techniques.     

False allegation of child abduction

Cases in which a child has been falsely reported as missing or abducted can be extremely challenging to the law enforcement agencies responsible for their investigation. In the absence of a witnessed abduction or an obvious crime scene, it is difficult to determine whether a child has actually been abducted or has become a victim of a homicide and a false allegation. The purpose of this study was to examine falsely alleged kidnapping cases and identify successful investigative strategies. Sixty-one adjudicated false allegation cases involving 66 victims were analyzed. The mean age of the victim was 5 years. Victims came from generally unstable, high-risk family situations and were killed primarily by biological parents. Victims were killed because they were unwanted or viewed as an obstacle to a desired goal, or they were victims of abuse or maltreatment that ended in fatality.     

The forensic science use of reflective ultraviolet photography

Reflective ultraviolet photography has many forensic science applications particularly in child abuse, rape, homicide, and bite mark cases. The potential of this relatively simple and inexpensive procedure has not been fully explored. The procedure for its use in bite mark cases is presented.     

The collation of forensic DNA case data into a multi-dimensional intelligence database

The primary aim of any DNA Database is to link individuals to unsolved offenses and unsolved offenses to each other via DNA profiling. This aim has been successfully realised during the operation of the New Zealand (NZ) DNA Databank over the past five years. The DNA Intelligence Project (DIP), a collaborative project involving NZ forensic and law enforcement agencies, interrogated the forensic case data held on the NZ DNA databank and collated it into a functional intelligence database. This database has been used to identify significant trends which direct Police and forensic personnel towards the most appropriate use of DNA technology. Intelligence is being provided in areas such as the level of usage of DNA techniques in criminal investigation, the relative success of crime scene samples and the geographical distribution of crimes. The DIP has broadened the dimensions of the information offered through the NZ DNA Databank and has furthered the understanding and investigative capability of both Police and forensic scientists. The outcomes of this research fit soundly with the current policies of 'intelligence led policing', which are being adopted by Police jurisdictions locally and overseas.     

The AFSP Standard - a lesson for law enforcement agencies

Compliance with the AFSP (Association of Forensic Science Providers) Standard [1] which concerns the formulation of an evaluative opinion requires consideration of the defence case. This can be problematic for forensic scientists working with or for law enforcement agencies. Among the aims of law enforcement agencies is to secure a conviction while in many jurisdictions the forensic scientist owes an overriding duty to the Court. This casework report demonstrates that early consideration of the defence case by a forensic scientist complying with the AFSP Standard may help rather than hinder the prosecution. The dichotomy as to a conflict of interest for the scientist between supporting the police/prosecutors and being scientifically objective is shown to be a false dichotomy. Compliance with the Standard ensures that science is a better servant of justice.     

The stages of cybercrime investigations: Bridging the gap between technology examination and law enforcement investigation

Cybercrime investigation can be argued as still in its infancy. The technical investigation practices and procedures of global law enforcement are also still evolving in response to the growing threat of the cybercriminal. This has led to considerable debate surrounding the adequacy of current technical investigation models, examination tools and the subsequent capability of law enforcement to tackle cybercrime. To bridge the gap between low-level technology recovery and digital forensic examination, and to overcome the many technical challenges now faced by law enforcement; this paper presents an extended cybercrime investigation model capable of guiding the investigative practices of the broader law enforcement community. The Stages of Cybercrime Investigations discussed throughout this paper, demonstrate the logical steps and primary considerations vital to investigating cyber related crime and criminality. The model is intended to provide both technical and non-technical investigative resources, covering mainstream law enforcement, partner agencies and specialist technical services, with a formal and common structure when investigating the complex technical nature of cybercrime. Finally, the model is further aimed at providing cybercrime investigators with a means to consolidate understanding, share knowledge and communicate the resulting outcomes as an investigation moves through each relevant stage.     

Management of crime scene units by Quebec police senior managers: Insight on forensic knowledge and understanding of key stakeholders

What do policing leaders think and know of forensic science? Beyond crime scene investigators or detectives, how do police senior managers perceive the role, utility and limitations of forensic science? Very few empirical studies have addressed the issue. Forensic scientsts should be concerned about the perception that law enforcement senior managers have of their discipline for two reasons. First, strategic and financial decision-makers are obviously key players in the overall administration and provision of forensic science, either as a supervisor, money provider or as a customer. Second, literature has highlighted that other actors involved in forensic science underestimate the scope and possibilities offered by forensic science, hence limiting its exploitation and potential. Following interviews with 18 police senior managers from Quebec (Canada), this study shows that they generally restrict forensic science to a reactive discipline whose role and utility is to identify offenders and support the Court. This understanding of forensic science, like that of many others including a significant share of forensic scientists, differs from the perception of other police activities in modern law enforcement agencies where proactive action is sought. Considering these findings and the growing body of literature which calls for forensic science to connect more tightly with policing and security, we advocate a more extensive education of police leaders regarding the scope of forensic science.     

The New Trial by Ordeal: Rape Kits,Police Practices,and the Unintended Effects of Policy Innovation

One of the most highly touted improvements in the criminal justice response to rape has been the wide‐scale adoption of sexual assault nurse examiner (SANE) programs that provide specialized medical care and forensic evidence collection to victims. Though previous studies have emphasized the benefits of SANE programs in improving criminal case outcomes, this study illustrates how the post‐rape forensic examination can also discourage reporting, investigation, and prosecution. Interviews with local rape care advocates across the United States show how the increasing emphasis on forensic evidence collected through rape kits may provide an opportunity to reflect and enact persistent law enforcement stereotypes toward sexual assault complainants. Unless police resistance to taking rape seriously is confronted and addressed, even well‐intentioned policy reforms such as SANE programs may end up undermining—rather than enhancing—fair and thorough investigation of sexual assault allegations.     

BitTorrent Sync: First Impressions and Digital Forensic Implications

With professional and home Internet users becoming increasingly concerned with data protection and privacy, the privacy afforded by popular cloud file synchronisation services, such as Dropbox, OneDrive and Google Drive, is coming under scrutiny in the press. A number of these services have recently been reported as sharing information with governmental security agencies without warrants. BitTorrent Sync is seen as an alternative by many and has gathered over two million users by December 2013 (doubling since the previous month). The service is completely decentralised, offers much of the same synchronisation functionality of cloud powered services and utilises encryption for data transmission (and optionally for remote storage). The importance of understanding BitTorrent Sync and its resulting digital investigative implications for law enforcement and forensic investigators will be paramount to future investigations. This paper outlines the client application, its detected network traffic and identifies artefacts that may be of value as evidence for future digital investigations.     

Modeling Forensic DNA Database Performance*

Abstract: Over the past decade or more, DNA databases have been a focal point of development for the forensic field. Using this approach, forensic and law enforcement agencies have aided millions of investigations, many of which would remain unsolved but for the intelligence links provided from DNA database comparison. However, despite their widespread use and increasingly broad legislative and operational reach, there has been limited overarching performance modeling or reflection on drivers of operational or financial efficiency. This study derives an inferential model for DNA database performance using data from major national DNA database programs. Parameters that optimize desirable database outputs (matches) are isolated and discussed, as is an approach for maximizing financial efficiency and minimizing ethical impact. This research takes important steps toward identifying measures of performance for forensic DNA database operations.     

拘役执法证据问题之探析

近几年,针对拘役执法机构的诉讼和信访案件屡有发生,造成极为负面的社会影响。在当前形势下,无论是从提高教育矫治质量,还是有效控制和化解执法风险上讲,拘役执法机构应当强化证据意识,规范证据体系,严格证据审查与保全。     

The utilization of forensic science and criminal profiling for capturing serial killers

Movies and nightly television shows appear to emphasize highly efficient regimens in forensic science and criminal investigative analysis (profiling) that result in capturing serial killers and other perpetrators of homicide. Although some of the shows are apocryphal and unrealistic, they reflect major advancements that have been made in the fields of forensic science and criminal psychology during the past two decades that have helped police capture serial killers. Some of the advancements are outlined in this paper. In a study of 200 serial killers, we examined the variables that led to police focusing their attention on specific suspects. We developed 12 categories that describe how serial killers come to the attention of the police. The results of the present study indicate that most serial killers are captured as a result of citizens and surviving victims contributing information that resulted in police investigations that led to an arrest. The role of forensic science appears to be important in convicting the perpetrator, but not necessarily in identifying the perpetrator.     

A forensic image processing environment for investigation of surveillance video

We present an image processing software suite, based on the Matlab environment, specifically designed to be used as a forensic tool by law enforcement laboratories in the analysis of crime scene videos and images. Our aim is to overcome some drawbacks which normally appear when using standard image processing tools for this application, i.e. mainly the lack of full control and documentation on the operations which have been performed on the images, and the absence of new, more sophisticated algorithms which can provide improved performances and "make the difference" in critical cases.     

Meeting a Forensic Podiatry Admissibility Challenge: A Daubert Case Study

This article is an introduction to the United States Supreme Court's standard of admissibility of forensic evidence and testimony at trial, known as the Daubert standard, with emphasis on how this standard applies to the field of forensic podiatry. The author, a forensic podiatrist, provided law enforcement with evidence tying a bloody sock‐clad footprint found at the scene of a homicide to the suspect. In 2014, the author testified at a pretrial hearing, known as “a Daubert hearing,” to address the admissibility of this evidence in court. This was the first instance of forensic podiatry being the primary subject of a Daubert hearing. The hearing resulted in the court ordering this evidence admissible. The expert's testimony contributed to the suspect's conviction. This article serves as a reference for forensic podiatrists and experts in similar fields that involve impression evidence, providing evidentiary standards and their impact on expert evidence and testimony.     

The Kodak Syndrome: Risks and Opportunities Created by Decentralization of Forensic Capabilities

Forensic science laboratories are being challenged by the expanding decentralization of forensic capabilities, particularly for digital traces. This study recommends laboratories undertake digital transformations to capitalize on the decentralization movement, develop a more comprehensive understanding of crime and security‐relevant problems, and play a more central role in problem‐solving collaboratively with law enforcement organizations and other stakeholders. A framework for the bilateral transfer of information and knowledge is proposed to magnify the impact of forensic science laboratories on abating crime, strengthening security, and reinforcing the criminal justice system. To accomplish digital transformations, laboratories require personnel with different expertise, including investigative reasoning, knowledge codification, data analytics, and forensic intelligence. Ultimately, this study encourages managers, educators, researchers, and policymakers to look beyond the usefulness of forensic results for solving individual investigations, and to realize the value of combined forensic knowledge and intelligence for developing broader strategies to deal with crime in digitalized society.     

Automatic forensic face recognition from digital images.

Digital image evidence is now widely available from criminal investigations and surveillance operations, often captured by security and surveillance CCTV. This has resulted in a growing demand from law enforcement agencies for automatic person-recognition based on image data. In forensic science, a fundamental requirement for such automatic face recognition is to evaluate the weight that can justifiably be attached to this recognition evidence in a scientific framework. This paper describes a pilot study carried out by the Forensic Science Service (UK) which explores the use of digital facial images in forensic investigation. For the purpose of the experiment a specific software package was chosen (Image Metrics Optasia). The paper does not describe the techniques used by the software to reach its decision of probabilistic matches to facial images, but accepts the output of the software as though it were a 'black box'. In this way, the paper lays a foundation for how face recognition systems can be compared in a forensic framework. The aim of the paper is to explore how reliably and under what conditions digital facial images can be presented in evidence.     

Neonaticide: A Comprehensive Review of Investigative and Pathologic Aspects of 55 Cases

Analysis of neonaticide cases from a law enforcement perspective is virtually non-existent in the research literature. Nonetheless, law enforcement and prosecutors face unique challenges when investigating and prosecuting neonaticide; and a specialized, informed approach is necessary. By highlighting the crime scene characteristics and autopsy findings of 55 neonaticide victims, the authors hope to assist the law enforcement and legal communities in their neonaticide investigations. Specifically, this article clarifies how neonaticide occurs by chronologically examining the pregnancy, the birth and death of the infant, the subsequent crime scene (or scenes) and the pathological findings. The article also highlights the potential challenges that may arise during investigation and prosecution of these cases in addition to providing the forensic community with recommended investigative techniques.     

Forensic palynology: why do it and how it works

Forensic palynology has been a law enforcement tool for over 50 years. Forensic palynology is the application of pollen and spores in solving legal issues, either civil or criminal. Pollen and spores can be obtained from an extremely wide range of items, including bodies. Pollen and spores provide clues as to the source of the items and the characteristics of the environments from which the material on them is sourced. Their usefulness lies in a combination of their abundance, dispersal mechanisms, resistance to mechanical and chemical destruction, microscopic size, and morphology. Their often complex morphology allows identification to an individual parent plant taxon that can be related to a specific ecological habitat or a specific scene. Pollen and spore assemblages characterise different environments and scenes and can easily be picked up and transported away from scenes of interest without providing any visual clue to a suspect as to what has occurred. With so many publications and high-profile cases involving forensic palynology and environmental analysis now receiving publicity, the future of this branch of forensic science is assured. Furthermore, with the development of multi-disciplinary approaches to environmental analyses of crime scenes, far more detailed information is now available to law enforcement agencies, enabling them to determine with greater accuracy what may have happened during the commission of criminal activities.     

iCOP: Live forensics to reveal previously unknown criminal media on P2P networks

The increasing levels of criminal media being shared in peer-to-peer (P2P) networks pose a significant challenge to law enforcement agencies. One of the main priorities for P2P investigators is to identify cases where a user is actively engaged in the production of child sexual abuse (CSA) media – they can be indicators of recent or on-going child abuse. Although a number of P2P monitoring tools exist to detect paedophile activity in such networks, they typically rely on hash value databases of known CSA media. As a result, these tools are not able to adequately triage the thousands of results they retrieve, nor can they identify new child abuse media that are being released on to a network. In this paper, we present a new intelligent forensics approach that incorporates the advantages of artificial intelligence and machine learning theory to automatically flag new/previously unseen CSA media to investigators. Additionally, the research was extensively discussed with law enforcement cybercrime specialists from different European countries and Interpol. The approach has been implemented into the iCOP toolkit, a software package that is designed to perform live forensic analysis on a P2P network environment. In addition, the system offers secondary features, such as showing on-line sharers of known CSA files and the ability to see other files shared by the same GUID or other IP addresses used by the same P2P client. Finally, our evaluation on real CSA case data shows high degrees of accuracy, while hands-on trials with law enforcement officers demonstrate the toolkit's complementarity to extant investigative workflows.