Linking Crimes Using Behavioural Clues: Current Levels of Linking Accuracy and Strategies for Moving Forward

Abstract

The number of published studies examining crime linkage analysis has grown rapidly over the last decade, to the point where a special issue of this journal has recently been dedicated to the topic. Many of these studies have used a particular measure (the area under the receiver operating characteristic curve, or the AUC) to quantify the degree to which it is possible to link crimes. This article reviews studies that have utilised the AUC and examines how good we are currently at linking crimes (within the context of these research studies) and what factors impact linking accuracy. The results of the review suggest that, in the majority of cases, moderate levels of linking accuracy are achieved. Of the various factors that have been examined that might impact linking accuracy, the three factors that appear to have the most significant impact are crime type, behavioural domain, and jurisdiction. We discuss how generalisable these results are to naturalistic investigative settings. We also highlight some of the important limitations of the linking studies that we reviewed and offer up some strategies for moving this area of research forward. Copyright © 2013 John Wiley & Sons, Ltd.Key words: crime linkage analysis; serial crime; behavioural consistency Research suggests that the majority of crime is committed by a minority of offenders (Paulsen, Bair, & Helms, 2009). Given this, police investigators will often face the difficult task of determining whether a set of crimes has been committed by the same offender. If high quality physical evidence is available at crime scenes, the task of determining whether multiple crimes were committed by the same offender is relatively straightforward, although not necessarily without challenges (Burrows, Tarling, *Correspondence to: Craig Bennell, Department of Psychology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6. E-mail: craig_bennell@carleton.ca Journal of Investigative Psychology and Offender Profiling J. Investig. Psych. Offender Profil. 11: 29-56 (2014) Published online 26 July 2013 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002DOI: 10. /jip.1395 Copyright © 2013 John Wiley & Sons, Ltd.Mackie, Poole, & Hodgson, 2005).1 When such evidence is lacking, however, the linking task can become much more difficult. In these cases, the behaviours exhibited by offenders across the crimes they have committed are often used to establish crime linkages (Grubin, Kelly, & Brunsdon, 2001). The primary task when taking such an approach is to identify stable but distinct patterns of behaviour in an offender's crimes, which allow one to distinguish between that offender's crimes and those of other offenders.One of the ultimate goals for researchers in this area is to identify approaches for analysing the behavioural clues left by offenders that maximise linking accuracy (Bennell & Canter, 2002). It is doubtful that one can focus on any single factor to accomplish this goal. Instead, linking accuracy will likely be maximised by caref...

Can hard-to-solve one-off homicides be distinguished from serial homicides? Differences in offence behaviours and victim characteristics

“…Woodhams et al, 2007). A number of studies have found evidence for the assumptions of crime linkage in serial crime (for a review of the research to date on behavioural crime linkage, see Bennell et al, 2014). While serial homicide has been studied less than, for example, rape, a few studies have found serial homicide offenders to be somewhat consistent in their behaviour over the course of their series (Bateman and Salfati, 2007;Salfati and Bateman, 2005;Salfati et al, 2015;Santtila et al, 2008;Sorochinski and Salfati, 2010).…”

Crime linkage of sex offences in Japan by multiple correspondence analysis

“…Third, inter‐crime distance and temporal proximity were not included in the current variables, although these parameters have been associated with large AUC values in many linking studies of other types of crimes (cf. Bennell et al ., ). As Bennell et al () indicated, research examining the potential value of spatial and temporal variables in cases of sexual assault is lacking because the sample size of these studies is small, and crimes to be analyzed must be much more geographically and temporally dispersed than in analyses of other types of high‐volume property crimes.…”

“…Bennell et al ., ). As Bennell et al () indicated, research examining the potential value of spatial and temporal variables in cases of sexual assault is lacking because the sample size of these studies is small, and crimes to be analyzed must be much more geographically and temporally dispersed than in analyses of other types of high‐volume property crimes. The current study also excluded spatial and temporal variables, because it appeared obvious that linking crimes based on inter‐crime distance and temporal proximity would be highly accurate in the current sample; the sample consisted of incidents from a wide area (throughout Japan) over a number of years (over a decade).…”

“…The results indicated that certain features, in particular the distances between burglary locations, led to high levels of predictive accuracy, and that logistic regression analysis provided the basis for a diagnostic tool to distinguish between linked and unlinked crime pairs. After the study of Bennell and Canter (), several studies replicated the demonstration of the potential of logistic regression analysis for linking crimes using different data sources (For a review, see Bennell et al ., ).…”

“…Recognition that a number of crimes have been committed by a single perpetrator can lead to the development of efficient and productive investigative strategies, whereas failure to do so might delay the eventual apprehension of the offender (Grubin, Kelly, & Brunsdon, ). The number of published studies examining crime linkage analysis has grown rapidly over the past decade (Bennell, Mugford, Ellingwood, & Woodhams, ).…”