Behavioural case linkage with solved and unsolved crimes

Offender behaviour is used to distinguish between crimes committed by the same person (linked crimes) and crimes committed by different people (unlinked crimes) through behavioural case linkage. There is growing evidence to support the use of behavioural case linkage by investigative organisations such as the police, but this research is typically limited to samples of solved crime that do not reflect how this procedure is used in real life. The current paper extends previous research by testing the potential for behavioural case linkage in a sample containing both solved and unsolved crimes. Discrimination accuracy is examined across crime categories (e.g. a crime pair containing a car theft and a residential burglary), across crime types (e.g. a crime pair containing a residential burglary and a commercial burglary), and within crime types (e.g. a crime pair containing two residential burglaries) using the number of kilometres (intercrime distance) and the number of days (temporal proximity) between offences to distinguish between linked and unlinked crimes. The intercrime distance and/or the temporal proximity were able to achieve statistically significant levels of discrimination accuracy across crime categories, across crime types, and within crime types as measured by Receiver Operating Characteristic (ROC) analysis. This suggests that behavioural case linkage can be used to assist the investigation, detection and prosecution of prolific and versatile serial offenders.     

Testing the impact of group offending on behavioural similarity in serial robbery

Behavioural case linkage assumes that offenders behave in a similar way across their crimes. However, group offending could impact on behavioural similarity. This study uses robbery data from two police forces to test this by comparing the behavioural similarity of pairs of lone offences (LL), pairs of group offences (GG) and pairs of offences where one crime was committed alone and the other in a group (GL). Behavioural similarity was measured using Jaccard's coefficients. Kruskal–Wallis tests were used to examine differences between the three categories within the linked samples. No statistically significant differences were found for linked GG compared to linked LL pairs. However, differences emerged between GL and the other categories for some behaviours (especially control) suggesting caution should be applied when linking group and lone offences committed by the same perpetrator. Differences between linked and unlinked pairs were assessed using receiver operating characteristic. The results suggest it is possible to distinguish between linked and unlinked pairs based on behaviour especially within the GG and LL categories. There were, however, fewer significant findings for the GL sample, suggesting there may be issues linking crimes where the offender commits one crime as part of a group and the other alone.     

Linking commercial burglaries by modus operandi: tests using regression and ROC analysis.

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.     

A Test of Case Linkage Principles with Solved and Unsolved Serial Rapes

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.     

The psychology of linking crimes: A review of the evidence

Purpose . This paper is concerned with case linkage, a form of behavioural analysis used to identify crimes committed by the same offender, through their behavioural similarity. Whilst widely practised, relatively little has been published on the process of linking crimes. This review aims to draw together diverse published studies by outlining what the process involves, critically examining its underlying psychological assumptions and reviewing the empirical research conducted on its viability. Methods . Literature searches were completed on the electronic databases, PsychInfo and Criminal Justice Abstracts, to identify theoretical and empirical papers relating to the practice of linking crimes and to behavioural consistency. Results . The available research gives some support to the assumption of consistency in criminals' behaviour. It also suggests that in comparison with intra‐individual variation in behaviour, inter‐individual variation is sufficient for the offences of one offender to be distinguished from those of other offenders. Thus, the two fundamental assumptions underlying the practice of linking crimes, behavioural consistency and inter‐individual variation, are supported. However, not all behaviours show the same degree of consistency, with behaviours that are less situation‐dependent, and hence more offender‐initiated, showing greater consistency. Conclusions . The limited research regarding linking offenders' crimes appears promising at both a theoretical and an empirical level. There is a clear need, however, for replication studies and for research with various types of crime.     

Using data on offender mobility in ecological research

This article presents some findings on neighborhood structure, police recorded crime, and offender mobility for the city of Utrecht, the Netherlands. The highest crime rates were found in the inner-city neighborhoods. The findings further show that the occurrence of different types of petty crime in residential neighborhoods is associated with different neighborhood characteristics. It was found that offenders reside predominantly in lower-social status neighborhoods. Using data on offender mobility it is shown that violent crime and vandalism are the more locally committed crimes, as compared to residential burglary and other property crime. Finally, it is proposed that data on offender mobility can be used to gain more insight into the link between certain neighborhood characteristics and crime.     

The development of a filter model for prioritising suspects in burglary offences

Abstract

This paper discusses the development of a filter model for prioritizing possible links in dwelling burglary. The filters utilize the central aspects of crime scene information that is available and accessible to investigators in burglary, namely geo-spatial, temporal, behavioural, and dwelling information. The proposed filters were analysed using a sample of 215 dwelling burglaries committed by 43 serial burglars (i.e. 5 offences each) in order to determine the sequence in which the filters should be considered in prioritizing possible linked offences. The results indicated that the following order (i.e. better performance to worse performance) was most effective at linking offences, utilizing: (1) geo-spatial information, (2) temporal aspects, (3) behavioural information and, lastly, (4) dwelling characteristics. Specifically, the results indicated that offences in close proximity to one another should be given priority. Further, any offence occurring within a 28-day span before or after the index offence should be given priority. The paper argues that behavioural and dwelling characteristics are less effective for linking than geo-spatial and temporal information because the former two aspects are influenced significantly by situational and contextual cues on offender decision-making.     

Another look at across-crime similarity coefficients for use in behavioural linkage analysis: an attempt to replicate Woodhams,Grant, and Price (2007)

Abstract

In the absence of physical evidence, investigators must often rely on offence behaviours when determining whether several crimes are linked to a common offender. A variety of factors can potentially influence the degree to which accurate linking is possible, including the similarity coefficient used to assess across-crime similarity. The current study examines the performance of two similarity coefficients that have recently been compared to one another, Jaccard's coefficient (J) and the taxonomic similarity index (Δ_s), using samples of two crime types, serial homicide (N=237) and serial burglary (N=210). In contrast to previous research, the results indicate that Δ_s does not significantly outperform J with respect to linking accuracy. In addition, both coefficients lead to higher levels of linking accuracy in cases of serial homicide compared to serial burglary. Potential explanations for these findings are presented and their implications are discussed.     

New methods for examining expertise in burglars in natural and simulated environments: preliminary findings

Expertise literature in mainstream cognitive psychology is rarely applied to criminal behaviour. Yet, if closely scrutinised, examples of the characteristics of expertise can be identified in many studies examining the cognitive processes of offenders, especially regarding residential burglary. We evaluated two new methodologies that might improve our understanding of cognitive processing in offenders through empirically observing offending behaviour and decision-making in a free-responding environment. We tested hypotheses regarding expertise in burglars in a small, exploratory study observing the behaviour of ‘expert’ offenders (ex-burglars) and novices (students) in a real and in a simulated environment. Both samples undertook a mock burglary in a real house and in a simulated house on a computer. Both environments elicited notably different behaviours between the experts and the novices with experts demonstrating superior skill. This was seen in: more time spent in high value areas; fewer and more valuable items stolen; and more systematic routes taken around the environments. The findings are encouraging and provide support for the development of these observational methods to examine offender cognitive processing and behaviour.     

The relationship between the detection of acquisitive crime by forensic science and drug-dependent offenders

Drug- and nondrug-related acquisitive crime offences such as burglary, theft, and motor vehicle theft, were compared to assess whether drug abusers were more likely to be apprehended via forensic science techniques. Data were all acquisitive offences committed over a 6-year period within a police force area in England. Drug-dependent offenders committed a wider range of offence types than nondependent offenders, and they were significantly more likely to be detected via their DNA or fingerprints (p < 0.01). A logistic regression (n > 14,000) revealed a number of predictors that influence the detection of the crime by forensic techniques. The results indicate that a number of these predictors are of statistical significance; the most significant of these being drug use by the offender with sex, ethnicity, and employment status also being relevant. Age of the offender and number of offences committed were found not to be significant. Of the four hypotheses considered to explain this, the most likely was thought to be the physical and mental impact of drug use on crime scene behavior. Consideration is given to the disciplines of forensic science and forensic psychology working closely together to distinguish factors that influence crime scene behavior.     

A city-level analysis of property crime clearance rates

Theft, burglary, and vehicle theft are among the most frequently committed and least commonly cleared Part I offenses in the United States, but have received disproportionately little attention in the clearance literature. This study contributes to recent efforts to remedy this shortage by presenting offense-specific analyses of burglary, larceny, and vehicle theft clearance rates in a sample of 110 large US cities. Data were gathered from the Uniform Crime Report, the Law Enforcement Management and Administrative Statistics survey, and the American Community Survey. Independent variables comprised social disorganization measures (e.g. residential instability, poverty, etc.) and policing variables, including the use of broken windows policing. Although broken windows policing is related to higher clearance rates in a few prior studies, that effect was not observed in the present work. Racial diversity and police spending per capita (which were negatively associated with clearance rates) were the only variables that were significantly associated with the clearance of all three crimes.     

Offender as Forager? A Direct Test of the Boost Account of Victimization

Recent research has demonstrated that burglary clusters in space and time, resulting in temporal changes in crime hotspot patterns. Offender foraging behavior would yield the observed pattern. The offender as forager hypothesis is tested by analyzing patterns in two types of acquisitive crime, burglary and theft from motor vehicle (TFMV). Using a technique developed to detect disease contagion confirms that both crime types cluster in space and time as predicted, but that the space–time clustering of burglary is generally independent of that for TFMV. Police detections indicate that crimes of the same type occurring closest to each other in space and time are those most likely to be cleared to the same offender(s), as predicted. The implications of the findings for crime forecasting and crime linkage are discussed.

ROLE OF THE STREET NETWORK IN BURGLARS' SPATIAL DECISION‐MAKING*

Explaining why crime is spatially concentrated has been a central theme of much criminological research. Although various theories focus on neighborhood social processes, environmental criminology asserts that the physical environment plays a central role by shaping people's activity patterns and the opportunities for crime. Here, we test theoretical expectations regarding the role of the road network in shaping the spatial distribution of crime and, in contrast to prior research, disentangle how it might influence offender awareness of criminal opportunities and the supply of ambient guardianship. With a mixed logit (discrete choice) model, we use data regarding (N = 459) residential burglaries (for the first time) to model offender spatial decision‐making at the street segment level. Novel graph theory metrics are developed to estimate offender awareness of street segments and to estimate levels of ambient guardianship, distinguishing between local and nonlocal guardianship. As predicted by crime pattern theory, novel metrics concerning offender familiarity and effort were significant predictors of residential burglary location choices. And, in line with Newman's (1972) concept of defensible space, nonlocal (local) pedestrian traffic was found to be associated with an increase (decrease) in burglary risk. Our findings also demonstrate that “taste” preferences vary across offenders, which presents a challenge for future research to explain.     

Predicting offender home location in urban burglary series

Residential location of a criminal can be predicted statistically [M. Laukkanen, P. Santtila, Predicting the home location of a serial commercial robber, Forensic Sci. Int. 157 (2006) 71-82]. Examined were: accuracy of the technique for urban burglary series, correlations between way of committing burglary and distance and use of those correlations in enhancing prediction accuracy. Data: 78 residential burglary series from Greater Helsinki area, Finland. Series for which the home location prediction was made was never part of the predicting model. Distances between home and crime-site were short (Mdn 3.88km; IQR=1.16-10.10km). Search area of a perpetrator could be limited to 1.95% (Mdn, IQR=0.64-18.70%) of the total study area. For series which conformed to Circle Hypothesis (45%), search area was 0.84% (Mdn, IQR=0.51-2.34%). Correlations between crime features and distance were found to enhance accuracy when features of series hinted short distance: sub-model limited search area to 0.19% (Mdn, IQR=0.07-0.65%).     

论继承性共犯

继承性共犯,是指在先行为人已经实施了犯罪的手段行为或者结合犯的前一犯罪之后,以共同的犯罪故意单独或者帮助先行为人实施犯罪的目的行为或者结合犯的后一犯罪的犯罪人。继承性共犯只存在于两种犯罪形态中:一是由手段行为和目的行为结合而成的犯罪,二是结合犯。对继承性共犯应确定与被继承性共犯同样的罪名。     

EFFECTS OF ATTRACTIVENESS, OPPORTUNITY AND ACCESSIBILITY TO BURGLARS ON RESIDENTIAL BURGLARY RATES OF URBAN NEIGHBORHOODS

This study assesses the effects of attractiveness, opportunity and accessibility to burglars on the residential burglary rates of urban neighborhoods, combining two complementary lines of investigation that have been following separate tracks in the literature. As a complement to standard measures of attractiveness and opportunity, we introduce and specify a spatial measure of the accessibility of neighborhoods to burglars. Using data on about 25, 000 attempted and completed residential burglaries committed in the period 1996–2001 in the city of The Hague, the Netherlands, we study the variation in burglary rates across its 89 residential neighborhoods. Our results suggest that all three factors, attractiveness, opportunity and accessibility to burglars, pull burglars to their target neighborhoods.     

An exploration of burglary in the criminal histories of sex offenders referred for civil commitment

Commission of nonsexual crimes generally antedates officially recorded sexual offenses. In particular, burglary has been hypothesized to be a potential ‘stepping stone’ in the development of one's sexual criminal career in the same way that marijuana has often been considered a ‘gateway drug’ to more serious drug-related offenses. The present study examined the officially recorded criminal histories of 828 male sex offenders to determine the relevance of burglary in their criminal histories. One third of the men in the sample (n=281, 34%) had been charged at least once for burglary. These 281 men committed a total of 762 separate incidents of burglary. Offenders with at least one officially recorded charge for burglary (BSOs) were compared with those with no such charges (SOs). Next, the characteristics of each burglary were examined and four distinct types of burglary were identified: nonsexual, covertly sexual, overtly sexual, and combination burglary/rape. BSOs accrued twice as many charges as the SOs and were significantly more likely to have an earlier age of onset, a longer criminal career, more employment problems, elementary school problems, antisocial behavior, and substance abuse.     

Group size does matter: differences among sexual assaults committed by lone,double, and groups of three or more perpetrators

ABSTRACT

We compared a total of 340 sexual assault cases based on offender characteristics, victim characteristics, and offence behaviours to identify differences among sexual assaults committed by lone, double, and groups of three or more perpetrators in South Korea. Several differences were found among sexual assaults committed by varying numbers of offenders. First, lone, double, and groups of three or more perpetrators differed with respect to age, marital status, and employment status. Second, substantial differences in victim characteristics were observed with respect to age and the victim–offender (v–o) relationship. Third, significant differences in offence behaviours, including offence type, planning, method of approach, knife possession, and stealing property, were found. Furthermore, we identified several variables that significantly predict group size using logistic regression analyses. The study has theoretical implications for understanding how group dynamics influence the behaviours of rape perpetrators, and practical implications for victim treatment and offender intervention.     

Measuring the impact of forensic science in detecting burglary and autocrime offences

As UK investment in forensic science has increased, the government has taken a fresh interest in how far this has led to dividends in terms of the detection of crime and its reduction. The Home Office funded 'Pathfinder Project' sought to monitor and document the complex relationships between the collection and use of forensic material (looking at a range of forensic science techniques) and its impact on crime detection. The project specifically targeted the 'volume' crimes of burglary and vehicle crime. Detailed data was gathered on all stages of the process between the collection and use of forensic material and crime detection. The model falls into two conceptual phases--scene attendance to suspect identification and identification to detection. From the analysis it was found that approximately one third of burglary and autocrime scenes are visited by SOCOs. While scientific identifications are only made in a minority of burglary and autocrime offences overall, it belies their importance. About one in ten of burglary and autocrime cases are cleared up by the police and it is estimated that fingerprints and SGMPlus were a contributory factor in achieving one third of these clear ups.     

On the Limits of Social Control: Structural Deterrence and the Policing of “Suppressible” Crimes

The present study examined the relationships between patterns of police arrests and subsequent variations in robbery, burglary, and aggravated assault in New York City police precincts from 1989 to 1998. Grounded in the structural deterrence theoretical perspective, and using a two‐stage fixed‐effects statistical framework, the study found that while controlling for indicators of social disorganization, increases in arrest vigor (i.e., arrests per officer for violent crimes in each precinct and raw arrest counts) predicted decreases in robbery and burglary, but that the relationships were non‐linear: as arrest vigor increased, robbery and burglary crime decreased; when arrest thresholds were reached, however, both robbery and burglary crime rates became positively associated with arrest aggressiveness. Conversely, variations in aggressive arrest patterns had no significant effect on aggravated assault, supporting the suppressible crimes arguments that primarily economically motivated crimes, and those that tend to occur in public settings, are most likely deterred by aggressive police practices.