Introduction to the special issue on Bayesian journey-to-crime modelling

In this special issue of the Journal of Investigative Psychology and Offender Profiling, we explore a Bayesian approach to journey-to-crime (JTC) estimation with an emphasis on the statistical models used. The approach conceptualises the probability that an offender lives at one location as the product of the probability distribution from a JTC estimate along with the probability distribution of other offenders who committed crimes in the same locations. The Bayesian approach is appropriate as the second part is conditional on the first part. The introduction gives the background behind the methodology and suggests how future improvements can be made by integrating new information. Finally, the papers in the special issue are introduced. Copyright © 2009 John Wiley & Sons, Ltd.     

The mathematics of geographic profiling

We begin by describing some of the mathematical foundations of the geographic profiling problem. We then present a new mathematical framework for the geographic profiling problem based on Bayesian statistical methods that makes explicit connections between assumptions on offender behaviour and the components of the mathematical model. It also can take into account local geographic features that either influence the selection of a crime site or influence the selection of an offender's anchor point. Copyright © 2009 John Wiley & Sons, Ltd.     

Target selection patterns in rape

Both theoretical and empirical studies of decision making in target selection have shown that this process is highly dependent on the physical environment. However, research specifically investigating decision making in sex offenders' target selection is scarce. The aims of the current study were to (1) identify target selection patterns in a mixed sample of 78 Canadian and Portuguese adult rapists, (2) investigate how geographical decision making influences target selection patterns, and (3) test the influence of the type of environment on target selection patterns. The results indicate that Canadian and Portuguese rapists exhibit different target selection patterns but that their geographical decision making is congruent and consistent with the environment within which they operate. Copyright © 2010 John Wiley & Sons, Ltd.     

Crime scene actions and offender characteristics in a sample of Finnish stranger rapes

The crime scene actions employed by offenders in stranger rapes were analysed in relation to offender characteristics. Data were drawn from an official police database and consisted of stranger rapes occurring in Finland between 1992 and 2001 (n = 100). The structure of dichotomous variables derived through a content analysis of crime scene actions and offender characteristics were analysed with non‐metric multidimensional scaling (MDS). The first analysis revealed three separate action themes, with thematic emphases on Hostility, Involvement or Theft. The MDS‐solution for offender characteristics suggested four themes: Conventional; Psychiatric/Elderly; Criminal/Violent; and Criminal/Property. Each case was assigned to one of the themes or as a hybrid in order to analyse the associations between action themes and characteristics. The only significant association was found between the action theme, Theft and characteristics theme Criminal/Property. The results are discussed in relation to previous research. Copyright © 2004 John Wiley & Sons, Ltd.     

Serial murderers' spatial decisions: factors that influence crime location choice

The outcome of German serial murderer spatial decision making was measured as the straight‐line distance (km) between murderer home locations and each crime location (i.e. body recovery location). Geographic and series development data, as well as information on age, intelligence, motive, marital status, employment status, and mode of transportation of 53 German serial murderers was collected from police and prosecution service files and judicial verdict records. Potential effects of the aforementioned factors on spatial decisions were assessed. Results showed that 63% of the murderers lived within 10 km of their crime locations. Home‐to‐crime distance was negatively correlated with murderer age and positively correlated with murderer IQ score. Results also showed that the mode of transportation used by murderers had an effect on their spatial decisions. Results are discussed in terms of understanding serial murderer spatial decision‐making and implications for police investigations. Copyright © 2005 John Wiley & Sons, Ltd.     

State resident volunteering and health are unrelated when neuroticism is controlled: Nomothetic evidence using the 50 states of the USA as analytical units

ABSTRACT

This research challenges the claim that engaging in formal volunteering improves health. Using data for the 50 American states pertaining to 2015–2016, multiple regression equations with differing control and entry order demonstrated the capacity of state resident neuroticism to eliminate relations between state volunteering rates and state health outcomes. In Study 1, with state SES, White population percent, urban population percent, and health environment considered and controlled, volunteering accounted for 11.5% of state health variance. However, with neuroticism entered between the demographic controls and volunteering, neuroticism accounted for 18.0% but additional variance accounted for by volunteering was reduced to 0.7%. Similarly, in Study 2, with data for those 65 and older, the results were replicated. It is speculated that higher neuroticism produces social anxiety that discourages volunteering and fosters poorer health at both the individual and the state level for the general population and for those 65 and over.     

The Jack the Ripper murders: a modus operandi and signature analysis of the 1888–1891 Whitechapel murders

A number of females, commonly recognized as 11 victims, were murdered in separate events in Whitechapel, London between 1888 and 1891. An evaluation of the murders revealed that six of those murders were linked by a number of distinct, personal signature characteristics, including picquerism, overkill, incapacitation, domination and control, open and displayed, unusual body position, sexual degradation, mutilation, organ harvesting, specific areas of attack, preplanning and organization, and a combination of signature features. The signature characteristics observed in these infamous Jack the Ripper murders were compared to a 1981–1995 cohort of 3359 homicide cases from Washington State's HITS database. The analysis revealed that the signature displayed in six of the Whitechapel murders was extremely rare. There were only six records of female victims, one a prostitute, with probed, explored, or mutilated body cavities. There were only two cases, both females who were not prostitutes, where the body was left in an unusual position and body cavities were explored, probed, or mutilated. Copyright © 2005 John Wiley & Sons, Ltd.