Search results

Crime linkage analysis (CLA) can be applied in the police investigation-phase to sift through a database to find behaviorally similar cases to the one under investigation and in the trial-phase to try to prove that the perpetrator of two or more offences is the same, by showing similarity and distinctiveness in the offences. Lately, research has moved toward more naturalistic settings, analyzing data sets that are as similar to actual crime databases as possible. One such step has been to include one-off offences in the data sets, but this has not yet been done with homicide. The purpose of this paper is to investigate how linking accuracy of serial homicide is affected as a function of added hard-to-solve one-off offences.

A sample (N = 117–1160) of Italian serial homicides (n = 116) and hard-to-solve one-off homicides (n = 1–1044, simulated from 45 cases) was analyzed using a Bayesian approach to identify series membership, and a case by case comparison of similarity using Jaccard’s coefficient. Linking accuracy was evaluated using receiver operating characteristics and by examining the sensitivity and specificity of the model.

After an initial dip in linking accuracy (as measured by the AUC), the accuracy increased as more one-offs were added to the data. While adding one-offs made it easier to identify correct series (increased sensitivity), there was an increase in false positives (decreased specificity) in the linkage decisions. When rank ordering cases according to similarity, linkage accuracy was affected negatively as a function of added non-serial cases.

While using a more natural data set, in terms of adding a significant portion of non-serial homicides into the mix, does introduce error into the linkage decision, the authors conclude that taken overall, the findings still support the validity of CLA in practice.

This is the first crime linkage study on homicide to investigate how linking accuracy is affected as a function of non-serial cases being introduced into the data.

The purpose of this paper is to explore the differences (if any) between serial and hard-to-solve one-off homicides, and to determine if it is possible to distinguish the two types of homicides based on offence behaviours and victim characteristics.

A sample of 116 Italian serial homicides was compared to 45 hard-to-solve one-off homicides. Hard-to-solve one-off homicides were defined as having at least 72 hours pass between when the offence came to the knowledge of the police and when the offender was caught. Logistic regression was used to predict whether a killing was part of a series or a one-off offence.

The serial killers targeted more strangers and prostitutes, displayed a higher level of forensic awareness both before and after the killing, and had more often an apparent sexual element in their offence. Conversely, the one-off homicides were found to include more traits indicative of impulsive and expressive behaviour. The model demonstrated a good ability (AUC=0.88) to predict whether a homicide belonged to the serial or one-off category.

The findings should be replicated using local homicide data to maximise the validity of the model in countries outside of Italy.

Being able to distinguish between serial and one-off homicides based on information available at a new crime scene could be practically useful for homicide investigators managing finite resources.

Studies comparing serial homicides to one-off homicides are scarce, and there are no studies explicitly trying to predict whether a homicide is an isolated case or part of a series.

Homicidal behaviour is influenced by a complex interaction of behavioural, situational and environmental factors that raise many challenging psychological questions. A large and continually growing body of research has explored the crime of homicide, its epidemiology, victims and perpetrators. The area is developing rapidly, opening up new avenues of study. The paper aims to discuss these issues.

This special issue of the Journal of Criminal Psychology brings together an exciting array of papers on homicidal behaviour, examining a wide range of issues including juvenile homicide perpetrators, school shootings, child homicide, homicide-suicide and differences in offence behaviours and victim characteristics between hard-to-solve one-off homicides and serial homicides.

The range of papers included in this special edition cover a wide range of aspects of homicidal behaviour, reflecting the importance of – and the need for – applied research moving away from examining general homicide to specialised research focusing on subtypes of homicide and subgroups of homicide offenders. A research agenda is proposed.

This editorial gives an introduction to the themes explored in this special issue and provides an overview of the selected papers.

Purpose – The purpose of this chapter is to explore homicide trends in Trinidad and Tobago, to describe the factors that impact the risk for homicide perpetration and victimization, and to discuss the effectiveness of strategies implemented by law enforcement agencies to prosecute homicide cases.

Design/methodology/approach – The chapter employs a detailed review of relevant literature to explore homicide trends and the strategies instituted to investigate and prosecute this criminal offense.

Findings – Our findings suggest that homicide victimization and perpetration is concentrated among young men of African descent, who reside in underprivileged communities with a high population density. Gang violence prompted by a narco-drug economy, coupled with gun violence, accentuates the risk of homicide perpetration and victimization. As homicide rates remained high, law enforcement officials in Trinidad and Tobago were ill equipped to investigate and make arrests in these offenses.

Originality/value – This chapter adds to the literature on homicide in Trinidad and Tobago by (1) showing that geographic and demographic factors structure homicide victimization and (2) exploring how the political economy of drugs in the Caribbean contributes to murder.

The Violent Crime Linkage Analysis System (ViCLAS) is a computerised database which is used by law enforcement in several countries to find potential links between serial violent crimes. In 2012, Bennell, Snook, MacDonald, House and Taylor identified a number of assumptions that must be valid for these computerised systems to be effective.

This paper revisits and expands on these assumptions with specific reference to the use of ViCLAS, looking at research that has been conducted since this 2012 review and outlining where research is still outstanding.

The importance of evaluating ViCLAS is highlighted in this paper.

Particularly, the research agenda highlights how the practice of comparative case analysis when using ViCLAS could be improved.

To the best of the authors’ knowledge, this is the first review of the research dedicated specifically to the evaluation of ViCLAS.

The purpose of this paper is to provide the reader with senior investigating officer (SIO) perspectives of their understanding of gang-related homicide and associated investigative challenges.

A phenomenological design was utilised in this study. In sum, 15 SIOs from the Metropolitan Police Service were interviewed using a semi-structured interview and analysed using thematic analysis.

It was found that the original typology of “gang homicide” might be too narrow and focus should be paid to “gang-related homicide”, characterised via motive behind the offence. This type of homicide exhibited specific characteristics (e.g. violent nature, large potential scene and pool of suspects) and investigative challenges which made it different from other types of homicide (e.g. complexity, need for more resources, managing unwilling witnesses, managing media interest, specific evidence challenges, need for thorough risk assessments). The need for expertise in the deployment of officers was highlighted and related to the desire for more continuing professional development (CPD).

Gang-related homicide is especially challenging, but due to its volume, SIOs in London developed a sort of “muscle memory” – something that other police services do not have, even though the “gang problem” is spreading outside of metropolitan areas. Support for changes (e.g. in the utility of community impact assessment) and non-standard procedures (e.g. consideration of covert operations early on) should be discussed in further training and manual development. More attention needs to be paid to the synthesis of experience, expertise and science, SIOs being especially interested in debriefs and CPD opportunities. Multi-agency training is key for homicide investigators, relating to the complex nature of gang-related homicide and relevant safeguarding issues. Resourcing is a clear issue relating to the increase in gang-related homicide, as well as its investigation.

This is the first research into investigative challenges of gang-related homicide in England and Wales, and the findings can be utilised by all police services who may be dealing with gangs in their area. The findings can also support calls for change and development within services.

The purpose of this paper is to suggest two things: first, that the scientific and technological developments and increased regulation that have shaped homicide investigations in England and Wales over the last few decades have provided today’s investigators with opportunities not available to their predecessors, and play a key role in solving unsolved homicides. Second, however, the authors suggest that such developments have created new challenges for investigators, challenges that impede current investigations, potentially creating the future unsolved cases.

This paper draws on two qualitative studies that comprised over eight months of ethnographic research, observations, interviews with serving and retired homicide detectives and case file analysis.

The widespread changes to homicide investigations in England and Wales have been valuable in many respects, notably, they have allowed detectives to look back in time and bring longstanding unsolved cases to a close. However, change, although well intentioned, might actually be creating future cold cases as detectives endeavour to manage the volume of information now generated during investigations, fast evolving scientific and technological techniques and an increase in bureaucracy.

This study is helpful for: improving investigative practice; learning from change; reducing unsolved homicides vs a rise in new cold cases; and innovative and entrepreneurial investigators.

Utilising qualitative research, this paper contributes to the academic literature exploring homicide investigation in England and Wales, offering insight into the challenges facing detectives and the potential impact of these upon solving past and present homicide cases.

The purpose of this study was to contribute to the evidence base by analysing the characteristics and motives of homicides involving acts of dismemberment.

The current study explored offence, victim and offender characteristics and the motives for 71 homicides involving dismemberment using open source data. All cases included in this study were investigated in the UK between 1970 and 2016. A non-metric multi-dimensional scaling procedure smallest space analysis (SSA) was used to explore the characteristics and motives derived from a content analysis of homicide data sourced online.

A distinction between expressive and instrumental characteristics was observable with three thematic regions identified: instrumental – defensive, instrumental – predatory and expressive – affective. Support was found for previously identified motives for criminal dismemberment, with defensive being the most common motive identified in 63% (N = 45) of the cases.

The implications of the findings are discussed with suggestions made for future research. The findings have practical implications for assisting law enforcement and forensic and clinical practitioners in further understanding offenders who engage in homicidal dismemberment. This includes aiding homicide investigations, in terms of supporting investigators to draw upon offence, victim and offender characteristics and motives for homicides involving acts of dismemberment. Differentiation between cases of dismemberment and understanding of motives also has practical implications for the development of interventions and treatment pathways for homicide offenders who dismember victims.