No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
A permutation test to identify important attributes for linking crimes of serial offenders
Abstract
The modus operandi (MO) of a crime describes the unique characteristics that an offender imparts to it. Although in some instances, a serial offender's behavior is circumstantial, some MO behaviors may be consistent from one crime to the next. By investigating these behaviors, similar crimes can be linked to the same individual, but some attributes describing a crime may be more important for linking than others. Two strategies have historically been used to link crimes. One relies on expert criminal judgment, which may require manually sifting through thousands of crime records. In the second, similar attributes are grouped, and logistic regression is applied to coarse frequency summaries of those groupings. In this work, we introduce an intuitive statistical permutation test for assessing the importance of individual attributes in linking crimes, and we show how the results can be used to weight each one's importance to link crimes. By using the serial offenses of four sets of residential burglaries and six sets of robberies identified in Tempe, Arizona, the test is illustrated, and differences among attribute importance of these two types of crimes are highlighted. We demonstrate greater success in linking crimes when the test results are incorporated into a linking analysis. Copyright © 2013 John Wiley & Sons Ltd
... In the last type of approach, crime series clustering, all the clusters are found simultaneously. 8,[27][28][29][30][31][32][33][34][35] One of the earliest approaches we know of for clustering crimes is that of Dahbur and Muscarello, 29 who used a neural network approach. (This method had some serious flaws that required extensive heuristic post-processing after the clusters were created, but aimed at solving the more general problem of crime clustering.) ...
One of the most challenging problems facing crime analysts is that of identifying crime series, which are sets of crimes committed by the same individual or group. Detecting crime series can be an important step in predictive policing, as knowledge of a pattern can be of paramount importance toward finding the offenders or stopping the pattern. Currently, crime analysts detect crime series manually; our goal is to assist them by providing automated tools for discovering crime series from within a database of crimes. Our approach relies on a key hypothesis that each crime series possesses at least one core of crimes that are very similar to each other, which can be used to characterize the modus operandi (M.O.) of the criminal. Based on this assumption, as long as we find all of the cores in the database, we have found a piece of each crime series. We propose a subspace clustering method, where the subspace is the M.O. of the series. The method has three steps: We first construct a similarity graph to link crimes that are generally similar, second we find cores of crime using an integer linear programming approach, and third we construct the rest of the crime series by merging cores to form the full crime series. To judge whether a set of crimes is indeed a core, we consider both pattern-general similarity, which can be learned from past crime series, and pattern-specific similarity, which is specific to the M.O. of the series and cannot be learned. Our method can be used for general pattern detection beyond crime series detection, as cores exist for patterns in many domains.
This chapter begins by explaining the purposes of linking crimes committed by the same offender and what case linkage can add to a police investigation and prosecution. The various steps involved in the process of case linkage are explained. The assumptions of behavioral consistency and inter-individual behavioral variation, which case linkage rests on, are outlined, and the research that has begun to test these assumptions is reported. The effect of poor-quality data on the case linkage process and on empirical research is examined. Current methods and future developments for overcoming this difficulty are described. The obstacles to identifying linked crimes across police boundaries are discussed. Case linkage research and practice are compared with various criteria for expert evidence with promising results. The chapter closes by considering future avenues for research and practice in case linkage.
University students, police professionals, and a logistic regression model were provided with information on 38 pairs of burglaries, 20% of which were committed by the same offender, in order to examine their ability to accurately identify linked serial burglaries. For each offense pair, the information included: (1) the offense locations as points on a map, (2) the distance (in km) between the two offenses, (3) entry methods, (4) target characteristics, and (5) property stolen. Half of the participants received training informing them that the likelihood of two offenses being committed by the same offender increases as the distance between the offenses decreases. Results showed that students outperformed police professionals, that training increased decision accuracy, and that the logistic regression model achieved the highest rate of success. Potential explanations for these results are presented, focusing primarily on the participants' use of offense information, and their implications are discussed.
The aim of the present study was to investigate whether experienced car crime investigators have special expertise in the linking of car crime and what characterises effective decision‐making in this context. Groups of experienced car crime investigators, experienced other investigators, novice participants, and naive participants attempted to link 10 series of three car crimes while thinking aloud. The results showed that experience had an effect on actual and self‐assessed linking accuracy but not on processing speed. Linking accuracy was also related to the use of a limited subset of case characteristics. Characteristics used in successful linking were included in a multidimensional scaling analysis which showed that these characteristics could be used to link the cases together also automatically. The implications of the findings for car crime investigation and for the creation of automated decision‐support systems were discussed.
Personality psychologists have suggested that the context of a behaviour should be considered in studying behavioural consistency. They have operationalised this as studying ‘if (situation)–then (behaviour)’ contingencies and have demonstrated an association between situational similarity and behavioural consistency. Previous research of behavioural consistency in the forensic setting has tended to focus exclusively on the ‘then (behaviour)’ part of the contingency—the offender's behaviour. This paper considers methodological approaches that might be used to investigate whether situational similarity is associated with behavioural consistency, and to develop if–then contingencies. Seventy-eight offences by stranger sex offenders were subjected to constant comparison framework analysis to develop an offender behaviour checklist and a victim behaviour checklist, and a combination of constant comparison framework analysis and hierarchical cluster analysis were used to develop victim behavioural themes. Consistency in offender behaviour and similarity in victim behavioural themes (representing situational similarity) were measured using Jaccard's coefficient for offence pairs within 13 solved series of stranger sexual assaults. Correlational analyses were used to assess the relationship between situational similarity and behavioural consistency. Contrary to expectations, no relationship was found. The utility of linguistic computational programs in creating if(victim behaviour)–then(offender behaviour) contingencies was tested with encouraging results. However, little evidence of consistency in if(victim behaviour)–then(offender behaviour) contingencies was found within the offence series. Explanations are proposed for these novel findings and avenues for future research are suggested. Copyright © 2008 John Wiley & Sons, Ltd.
The purpose of this study is to determine if readily available information about commercial and residential serial burglaries, in the form of the offender's modus operandi, provides a statistically significant basis for accurately linking crimes committed by the same offender. Logistic regression analysis is applied to examine the degree to which various linking features can be used to discriminate between linked and unlinked burglaries. Receiver operating characteristic (ROC) analysis is then performed to calibrate the validity of these features and to identify optimal decision thresholds for linking purposes. Contrary to crime scene behaviours traditionally examined to link serial burglaries, the distance between crime site locations demonstrated significantly greater effectiveness as a linking feature for both commercial and residential burglaries. Specifically, shorter distances between crimes signalled an increased likelihood that burglaries were linked. Thus, these results indicate that, if one examines suitable behavioural domains, high levels of stability and distinctiveness exist in the actions of serial burglars, and these actions can be used to accurately link crimes committed by the same offender. Copyright © 2005 John Wiley & Sons, Ltd.
Abstract Highly clustered event sequences are observed in certain types of crime data, such as burglary and gang violence, due to crime specic patterns of criminal behavior. Similar clustering patterns are observed by seismologists, as earthquakes are well known to increase the risk of subsequent earthquakes, or aftershocks, nearby the location of an initial event. Space-time clustering is modeled in seismology by self-exciting point processes and the focus of this paper is to show that these methods are well suited for criminological applications. We,rst review self-exciting point processes in the context of seismology. Next, using crime data provided by the Los Angeles Police Department, we illustrate the implementation of self-exciting point processes for the purpose of crime modeling. We then test the predictive accuracy of a point process based forecasting strategy against a recently proposed crime hot-spotting strategy. Our,ndings show that the point process forecasts signicantly,outperform those of the crime hotspot maps. Department of Mathematics, University of California, Los Angeles Department of Criminology, University of California, Irvine 1
This chapter begins by explaining the purposes of linking crimes committed by the same offender and what case linkage can
add to a police investigation and prosecution. The various steps involved in the process of case linkage are explained. The
assumptions of behavioral consistency and inter-individual behavioral variation, which case linkage rests on, are outlined,
and the research that has begun to test these assumptions is reported. The effect of poor-quality data on the case linkage
process and on empirical research is examined. Current methods and future developments for overcoming this difficulty are
described. The obstacles to identifying linked crimes across police boundaries are discussed. Case linkage research and practice
are compared with various criteria for expert evidence with promising results. The chapter closes by considering future avenues
for research and practice in case linkage.
In light of the dearth of literature specifically on serial juvenile sex offenders, this chapter considers the findings of
research with juvenile sex offenders and juvenile repeat sex offenders with respect to what this might tell us about juvenile
serial sex offending and its investigation. The chapter reports on different types of juvenile sex offenders: those that offend
against younger children and those that offend against their peers or adults; those that assault as a group compared to those
who assault alone; and juvenile sex offenders who target strangers as victims, a group that may require particular attention
from police. Having reviewed this literature, the chapter discusses the implications of research on behavioral consistency
and what it may mean for the successful application of investigative techniques (e.g., offender profiling and case linkage)
to serial juvenile sexual crime. Finally, the offenses of a small sample of serial juvenile sex offenders are analyzed. The
characteristics of the offenders, the victims, and the offenses are described; and the degree of behavioral consistency seen
in the offending of this group is reported.
Case linkage involves identifying crime series on the basis of behavioral similarity and distinctiveness. Research regarding
the behavioral consistency of serial rapists has accumulated; however, it has its limitations. One of these limitations is
that convicted or solved crime series are exclusively sampled whereas, in practice, case linkage is applied to unsolved crimes.
Further, concerns have been raised that previous studies might have reported inflated estimates of case linkage effectiveness
due to sampling series that were first identified based on similar modus operandi (MO), thereby overestimating the degree
of consistency and distinctiveness that would exist in naturalistic settings. We present the first study to overcome these
limitations; we tested the assumptions of case linkage with a sample containing 1) offenses that remain unsolved, and 2) crime
series that were first identified as possible series through DNA matches, rather than similar MO. Twenty-two series consisting
of 119 rapes from South Africa were used to create a dataset of 7021 crime pairs. Comparisons of crime pairs that were linked
using MO vs. DNA revealed significant, but small differences in behavioral similarity with MO-linked crimes being characterized
by greater similarity. When combining these two types of crimes together, linked pairs (those committed by the same serial
offender) were significantly more similar in MO behavior than unlinked pairs (those committed by two different offenders)
and could be differentiated from them. These findings support the underlying assumptions of case linkage. Additional factors
thought to impact on linkage accuracy were also investigated.
KeywordsComparative case analysis–Linkage analysis–Behavioral linking–Sexual assault–Sexual offense
This article examines a process of behavioral analysis, referred to as linkage analysis, used in identifying sexual offenses that have been committed by the same offender. This type of analysis examines behavior that is contained in three distinct components of a crime, i.e., the modus operandi (MO) or the “how to” of a crime; the ritual or fantasy-based behaviors for a particular type or series of sexual crimes; the signature or unique combination of behaviors, which suggests that a series of crimes has been perpetrated by the same offender. Linkage analysis involves five assessment procedures: (1) gathering detailed, varied, and multisource documentation; (2) reviewing the documentation and identifying significant features of each crime individually across the series; (3) classifying the significant features of the crime as either MO and/or ritualistic constructs; (4) comparing the combination of MO and ritualistic features across the crimes to determine if a signature exists; (5) compiling a written analysis that details the conclusions derived from the available information. Results of this type of analysis can be used for investigative purposes and, in some instances, can help to inform the decision-making of the courts.
The present study investigated the possibility of statistically linking arson cases based on consistency of behaviors from one crime scene to another. Serial and spree arson cases were studied to differentiate underlying themes and to link cases committed by the same offender. The material consisted of 248 arson cases which formed 42 series of arsons. A content analysis using 45 dichotomous variables was carried out and principal components (PCA) analysis was performed to identify underlying themes. Summary scores reflecting the themes were calculated. Linking effectiveness was tested with a discriminant analysis using the summary scores. The PCA analysis was successful and underlying themes which were in accordance with previous studies could be identified. Six factors were retained, in the PCA. The linking of the arson cases was possible to a satisfactory level: 33% of the cases could be correctly linked and for over 50% of the cases, the series they actually belonged to was among the ten series identified as most probable on the basis of the linking analysis. From a practical point of view, the results could be used as a basis for developing support systems for police investigations of arson. © Copyright Springer, 2004
Case linkage, the identification of crimes suspected of being committed by the same perpetrator on the basis of behavioral similarity, and offender profiling, the inference of offender characteristics from offense behaviors, are used to advise police investigations and, in relation to case linkage, have been admitted in legal proceedings. Criteria for expert evidence, such as the Daubert criteria (Daubert v. Merrell Dow Pharmaceuticals, 1993), place stringent conditions on the admissibility of expert evidence. The future contribution of these practices to legal proceedings depends, in part, on whether they are underpinned by hypotheses that are testable and supported. The 3 hypotheses of offender behavioral consistency, of offender behavioral distinctiveness, and of a homology (direct relationship) between offender characteristics and behavior were empirically examined using a sample of serial commercial robberies. Support was found for the former 2 hypotheses but not for the last. The findings of the 2 studies have implications for the future development of these practices, for legal practitioners evaluating expert evidence, and for the implementation of public policy.
This paper uses statistical models to test directly the police practice of utilising modus operandi to link crimes to a common offender. Data from 86 solved commercial burglaries committed by 43 offenders are analysed using logistic regression analysis to identify behavioural features that reliably distinguish between linked and unlinked crime pairs. Receiver operating characteristic analysis is then used to assign each behavioural feature an overall level of predictive accuracy. The results indicate that certain features, in particular the distances between burglary locations, lead to high levels of predictive accuracy. This study therefore reveals some of the important consistencies in commercial burglary behaviour. These have theoretical value in helping to explain criminal activity. They also have practical value by providing the basis for a diagnostic tool that could be used in comparative case analysis.
This article examines a process of behavioral analysis, referred to as linkage analysis, used in identifying sexual offenses that have been committed by the same offender. This type of analysis examines behavior that is contained in three distinct components of a crime, that is, the modus operandi (MO) or the “how to” of a crime, the ritual or fantasy-based behaviors for a particular type or series of sexual crimes, the signature or unique combination of behaviors, which suggests that a series of crimes has been perpetrated by the same offender. Linkage analysis involves five assessment procedures: (1) gathering detailed, varied, and multisource documentation; (2) reviewing the documentation and identifying the significant features of each crime individually across the series; (3) classifying the significant features of the crime as either MO and/or ritualistic constructs; (4) comparing the combination of MO and ritualistic features across the crimes to determine if a signature exists; and (5) compiling a written analysis that details the conclusions derived from the available information. Results of this type of analysis can be used for investigative purposes and, in some instances, can help to inform the decision making of the courts.
. A new procedure is proposed for clustering attribute value data. When used in conjunction with conventional distance-based clustering algorithms this procedure encourages those algorithms to detect automatically subgroups of objects that preferentially cluster on subsets of the attribute variables rather than on all of them simultaneously. The relevant attribute subsets for each individual cluster can be different and partially (or completely) overlap with those of other clusters. Enhancements for increasing sensitivity for detecting especially low cardinality groups clustering on a small subset of variables are discussed. Applications in different domains, including gene expression arrays, are presented.
Using 31 unique crime series from two US cities, the spatial pattern that individual criminal decision makers follow is investigated. Locations within a city vary in the likelihood for crimes of a given type to occur, and this is accounted for by using kernel density estimation based on all crimes of each type. Kernel density estimation is highly influenced by the bandwidth, so an objective approach is used to select the estimate. Then, the kernel density estimate for each type of crime is incorporated in an inhomogeneous K-function that can identify significant spatial clustering and/or uniformity at various spatial scales for each crime series. We find that robbery series are more likely to exhibit uniformity than burglary series, which tend to show strong clustering. In addition, the order in which new crimes are added to a series is found to follow an interesting pattern that does not always support the theory of offender as forager in which criminals first cluster crimes and then gradually disperse them. Half of the robbery series exhibit a spatial distribution that begins dispersed and develops clusters as increasingly more events are added to the series, indicating that they often return to locations of earlier crimes after having committed crimes elsewhere.
A general coefficient measuring the similarity between two sampling units is defined. The matrix of similarities between all pairs of sample units is shown to be positive semidefinite (except possibly when there are missing values). This is important for the multidimensional Euclidean representation of the sample and also establishes some inequalities amongst the similarities relating three individuals. The definition is extended to cope with a hierarchy of characters.
Evidence about a suspect's behavioural similarity across a series of crimes has been presented in legal proceedings in at least three different countries. Its admission as expert evidence, whilst still rare, is becoming more common thus it is important for us to understand how such evidence is received by jurors and legal professionals. This article reports on a qualitative analysis of mock jurors' deliberations about expert linkage analysis evidence. Three groups of mock jurors (N = 20) were presented with the prosecution's linkage analysis evidence from the USA State v. Fortin I murder trial and expert evidence for the defence constructed for the purposes of the study. Each group was asked to deliberate and reach a verdict. Deliberations were video-recorded and subject to thematic content analysis. The themes that emerged were varied. Analysis suggested that the mock jurors were cautious of the expert evidence of behavioural similarity. In some cases they were sceptical of the expert. They articulated a preference that expert opinion be supported using statistics. Additional themes included jurors having misconceptions concerning what is typical offender behaviour during rape which suggests there is a need for expert linkage analysis evidence regarding behavioural similarities and the relative frequencies of crime scene behaviours. Copyright © 2010 John Wiley & Sons, Ltd.
This study examines the crime patterns of 76 New Zealand serial sexual offenders in order to determine the extent to which offenders display locational consistency in their choice of crime locations. More specifically, the hypothesis was that there would be intraseries consistency in the distances travelled (spatial consistency) and the characteristics of the crime sites selected (environmental consistency) by serial sexual offenders.
For spatial consistency to be tested, the distances travelled from home to offend and the criminal range for each offence series were analysed. Support was found for spatial consistency, and, in line with much overseas research, it was also found that the offenders typically did not travel very far from home to offend (median distance of 3 km).
The environmental consistency measure was made up of various physical, temporal, and contextual variables that described the environmental characteristics of an offence. As hypothesised, it was found that offenders displayed intraseries environmental consistency in offence site selection beyond the level of that expected by chance. The implications of this both for understanding offender spatial decision making and for geographical profiling are discussed. Copyright
A sample of serial stranger rape cases ( n = 43) that had occurred in Finland during the years 1983–2001 were studied with the objectives being to: (a) describe the characteristics of the offenders; (b) explore the structure of serial rape; and (c) demonstrate behavioural linkage through an analysis of the offenders' crime scene behaviour using both multidimensional scaling (MDS) and discriminant function analysis (DFA). The material was content analysed with regard to the occurrence of a number of dichotomous variables. The inter-relationships of the variables was studied using MDS. The analysis revealed two previously identified major modes of interaction with the victim: involvement and hostility. Employing MDS and DFA, it was shown that the offences of different offenders were distinguishable in terms of variation between the offences of different offenders and consistency within the offences of a single offender. Using DFA, the classification accuracy clearly exceeds that expected by chance, and 25.6% of the cases were classified without any error. The results are discussed in relation to their practical utility and previous studies. Copyright © 2005 John Wiley & Sons, Ltd.
Linkage analysis is a crucial part of the investigative process when faced with a possible series of related offences. Establishing behavioural consistency (i.e., offender's behaviours consistently present across the series) is at the core of linkage. Recent empirical studies have found little evidence of consistency looking at either individual or groups of behaviours in serial homicide. It is argued that behavioural changes are rooted in the changing cognitive strategies that offenders use to reach their ultimate goal (i.e. the commission of multiple homicides). Factors that could account for these changes include learning, situational factors, loss of control, and changes in the offender's fantasy. Patterns of behavioural change have been identified in serial crimes, such as rape. However, no empirical studies have looked at patterns of behavioural change in serial homicide. The present study examined patterns of consistency and change using a combination of thematic and behavioural subgroup approaches that use Multidimensional Scaling. Thematic differentiation indicative of behavioural manifestations of cognitive strategies was found in all three examined subgroups: planning, wounding, and offender–victim interaction, and patterns of change within these subgroups provided support for the above theories. Looking at behavioural patterns rather than individual behaviours, may be a more fruitful way of examining consistency in serial homicide, and could have significant implications for linkage analysis. Copyright © 2010 John Wiley & Sons, Ltd.
Whilst case linkage is used with serious forms of serial crime (e.g. rape and murder), the potential exists for it to be used with volume crime. This study replicates and extends previous research on the behavioural linking of burglaries. One hundred and sixty solved residential burglaries were sampled from a British police force. From these, 80 linked crime pairs (committed by the same serial offender) and 80 unlinked crime pairs (committed by two different serial offenders) were created. Following the methodology used by previous researchers, the behavioural similarity, geographical proximity, and temporal proximity of linked crime pairs were compared with those of unlinked crime pairs. Geographical and temporal proximity possessed a high degree of predictive accuracy in distinguishing linked from unlinked pairs as assessed by logistic regression and receiver operating characteristic analyses. Comparatively, other traditional modus operandi behaviours showed less potential for linkage. Whilst personality psychology literature has suggested we might expect to find a relationship between temporal proximity and behavioural consistency, such a relationship was not observed. Copyright © 2010 John Wiley & Sons, Ltd.
Over the past decade, a renewed interest in the analysis of crime hot-spots has emerged in the social and behavioral sciences.
Spurred by improvements in computing power, data visualization and geographic information systems, numerous innovative approaches
have materialized for identifying areas of elevated crime in urban environments. Unfortunately, many hot-spot analysis techniques
treat the spatial and temporal aspects of crime as distinct entities, thus ignoring the necessary interaction of space and
time to produce criminal opportunities. The purpose of this paper is to explore the utility of statistical measures for identifying
and comparing the spatio-temporal footprints of robbery, burglary and assault. Functional and visual comparisons for spatio-temporal
clusters are analyzed across a range of space–time values using a comprehensive database of crime events for Cincinnati, Ohio.
Empirical results suggest that robbery, burglary and assault have dramatically different spatio-temporal signatures.
Serial criminals are a major threat in the modern society. Associating incidents committed by the same offender is of great importance in studying serial criminals. In this paper, we present a new outlier-based approach to resolve this criminal incident association problem. In this approach, criminal incident data are first modeled into a number of cells, and then a measurement function, called outlier score function, is defined over these cells. Incidents in a cell are determined to be associated with each other when the score is significant enough. We applied our approach to a robbery dataset from Richmond, VA. Results show that this method can effectively solve the criminal incident association problem.
The purpose of the present study is to test the case linkage principles of behavioural consistency and behavioural distinctiveness using serial vehicle theft data. Data from 386 solved vehicle thefts committed by 193 offenders were analysed using Jaccard's, regression and Receiver Operating Characteristic analyses to determine whether objectively observable aspects of crime scene behaviour could be used to distinguish crimes committed by the same offender from those committed by different offenders. The findings indicate that spatial behaviour, specifically the distance between theft locations and between dump locations, is a highly consistent and distinctive aspect of vehicle theft behaviour; thus, intercrime and interdump distance represent the most useful aspects of vehicle theft for the purpose of case linkage analysis. The findings have theoretical and practical implications for understanding of criminal behaviour and for the development of decision-support tools to assist police investigation and apprehension of serial vehicle theft offenders.
"Delinquency in a Birth Cohort is a turning point in criminological research in the United States," writes Norval Morris in his foreword. "What has been completely lacking until this book is an analysis of delinquency in a substantial cohort of youths, the cohort being defined other than by their contact with any part of the criminal justice system." This study of a birth cohort was not originally meant to be etiological or predictive. Yet the data bearing on this cohort of nearly ten thousand boys born in 1945 and living in Philadelphia gave rise to a model for prediction of delinquency, and thus to the possibility for more efficient planning of programs for intervention. It is expert research yielding significant applications and, though largely statistical, the analysis is accessible to readers without mathematical training. "No serious scholar of the methods of preventing and treating juvenile delinquency can properly ignore this book."âLeRoy L. Lamborn, Law Library Journal "The magnitude of [this] study is awesome. . . . It should be a useful guide for anyone interested in the intricacies of cohort analysis."âGary F. Jensen, American Journal of Sociology "A book the student of juvenile delinquency will find invaluable."âCriminologist
William J. Bratton is Chief of the Los Angeles Police Department and former Chief of the NYPD. He is best known for leading
the development and expansion of COMPSTAT, the internationally acclaimed command accountability system that uses computer-mapping
technology and timely crime analysis to target emerging crime patterns and coordinate police response. Sean W. Malinowski,
Ph.D., is a Lieutenant with the LAPD serving as the Assistant Commanding Officer of the LAPD's Real-time Analysis and Critical
Response Division. He is a senior fellow with Long Island University's Homeland Security Management Institute. In this article,
they consider police performance management in practice, through the lens of Chief Bratton's own experience of reducing crime
in New York and Los Angeles. By measuring the performance of police managers whilst holding them to account for crimes, they
explain the role COMPSTAT played in fighting crime in these areas and look forward to see how police can continue to innovate
and expand upon existing police performance measures.
Intelligence analysis has emerged as an important component of contemporary policing strategies. Drawing upon qualitative data and a perspective informed by some of the concepts associated with the sociology of scientific knowledge, this paper provides an epistemologically oriented critique of some of the key techniques associated with crime analysis. Data presented suggest that crime analysis: is used in line with traditional modes of policing; is a way of claiming ‘scientific objectivity’ for police actions; and is largely shaped by police perspectives on data. It is argued that the sense of enhanced objectivity often attributed to the products of ‘intelligence work’ is frequently overstated. The products of crime analysis are better understood as an artefact of the data and methods used in their construction, rather than providing an accurate representation of any crime problems.
Establishing behavioral consistency in serial homicide offending behavior is essential when linking homicides together and to a common offender. An examination of 35 serial homicide behaviors utilized by 90 offenders in 450 serial homicide cases was carried out to identify whether these offenders consistently performed the same behaviors across their series of homicides and whether it is more effective to examine individual behaviors or groupings of behaviors in order to identify behavioral consistency. This study provides the first empirically based evidence testing the use of using single behaviors as linking factors in linking homicide cases in a series, and shows that this method has inherent difficulties in accomplishing this, thus providing the first wave of empirical testing that questions current theories in the literature on serial homicide, which has suggested that signatures or specific key behaviors are important in understanding the consistency in an offender's behavior across the crimes. Recommendations for future studies on linking using signatures are suggested, including a more in-depth qualitative empirical evaluation of individual series.
A new point process transition density model is proposed based on the theory of point patterns for predicting the likelihood of occurrence of spatial-temporal random events. The model provides a framework for discovering and incorporating event initiation preferences in terms of clusters of feature values. Components of the proposed model are specified taking into account additional behavioral assumptions such as the "journey to event" and "lingering period to resume act." Various feature selection techniques are presented in conjunction with the proposed model. Extending knowledge discovery into feature space allows for extrapolation beyond spatial or temporal continuity and is shown to be a major advantage of our model over traditional approaches. We examine the proposed model primarily in the context of predicting criminal events in space and time.
Lois de distribution florale
- Jaccard P