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Re-Conceptualizing "Cooling-Off Periods" in Serial Homicide
Abstract
Cooling-off periods have been described as the state of returning to the offender’s usual way of life between homicides (Burgess, 2006) and are a crucial factor in defining serial homicide (Douglas, Ressler, Burgess, & Hartman, 1986). If the clinical aspect referring to the offender’s emotional and motivational state is removed, these episodes can be aptly termed time intervals between homicides. Factors such as geography, victim selection, and the offender’s level of social involvement may instead serve as more appropriate starting points for studying this concept. In the present study, these factors were examined using 16 series containing 90 time intervals with a reported median interval length between events of 34.5 days.
... Research into serial homicide is thus dependent on further understanding the systematic underpinnings of emotional cool off periodswhich variables constitute an emotional cool-off occurring and which variables undermine the actual classification of serial homicide. Osborne and Salfati (2015) studied cool off period temporallystating the best way to define the phenomenon is to exclusively study temporal aspects rather than including any clinical applications of cooling-off from the crime. While researchers determined a median length of time intervals within a series as 34.5 days. ...
... While Osborne and Salfati (2015) found time to be the most crucial aspect of cool-off periods to investigate, the current results show time is not as influential as clinical factors in the cooling-off process as researchers suggested. Given the opportunity to include time in their reasoning, experts agreed most highly on the influence of 'Cognitive State' factors (emotional cool-off present) and 'Arousal' factors (emotional cool-off absent) as most the important reason, with time holding third and second places, respectively. ...
... Given the opportunity to include time in their reasoning, experts agreed most highly on the influence of 'Cognitive State' factors (emotional cool-off present) and 'Arousal' factors (emotional cool-off absent) as most the important reason, with time holding third and second places, respectively. Furthermore, previous research has determined at least 30 days must have lapsed between homicides in order for the perpetrator to have experienced a 'significant cooling-off period' and therefore, for the perpetrator to be considered serial (Holmes & Holmes, 1998;Osborne & Salfati, 2015), although more recently, Yaksic et al. (2021) noted that intervals between the kills can be as short as one day. Present findings challenge this ideology, as multiple scenarios ranged from 24 to 48 h and experts still perceived time to be influential in cool-off having occurred. ...
The Federal Bureau of Investigation coined the term ‘emotional cool-off period’ in relation to serial homicide defining it as any amount of time between kills where the perpetrator returns to their everyday life (Douglas et al., 1986). Since the term’s conception, cool-off periods have become a fundamental aspect of defining serial versus non-serial homicide cases in academia. Despite its usage frequency, it has been neither firmly defined nor empirically investigated. The present study aims to investigate the specific underpinnings of emotional cool-off periods in sexual homicide by utilising experts’ opinion in relation to distinguishing between serial and non-serial homicide cases. Twenty-eight experts took part in the study and they each scored 10 sexual homicide scenarios for emotional cool-off presence as well as influential factors they relied on when making their decision. The results indicated that inter-rater agreement was ‘poor’ across experts. When experts believed an emotional cool-off period was present, they relied on cognitive state indicators whereas when they believed an emotional cool-off period was absent they relied on evidence of arousal. The time was second most frequent factor. This suggests that experts prefer to base their judgement on the presence (rather than absence) of forensic evidence available to them.
... Multiple publications use a cooling-off period to distinguish between a mass/spree killer and serial killer, although it is not clearly defined (Bartol & Bartol, 2016;Choi & Lee, 2014;Geberth, 1986;Gresswell & Hollin, 1994;Miller, 2013). Researchers have used different terms either interchangeably or make small changes, such as: emotional cooling-off period (Douglas et al., 1986), inter-murder intervals (Simkin & Roychowdhury, 2011), time intervals between murders (Osborne & Salfati, 2014), and dormant period (Yaksic, 2015). Clear understanding of what is meant by 'cooling-off' allows investigators the opportunity to track or classify different typologies of killers. ...
... In addition, why does the length of these inter-murder-intervals change between killers? There are a handful of publications that explore the concept further (Osborne & Salfati, 2014;Simkin & Roychowdhury, 2011); however, more research is needed to understand what a cooling-off period may consist of, including the length, and behavioural characteristics. Moreover, research now needs to take a more focused, applied approach, as the ecological fallacy indicates that we cannot clearly apply aggregate data to individual cases. ...
... At present, there is no universally accepted definition and classification of the length of time a 'cooling-off' period lasts. There are relatively few studies that attempt to determine or measure different factors that may influence the duration, and the underlying understanding of what a cooling-off period encompasses (Lynes & Wilson, 2015;Osborne & Salfati, 2014). Further, there is disagreement within the literature on the standard length of a cooling-off period, with Geberth (2006) suggesting it could range from days to months and Bartol and Bartol (2008) suggesting it is more likely months or years. ...
Understanding cooling-off periods is an important step towards conceptualising life course events of serial killers, between their murders. Analysing the behaviours of serial killers between each homicide may give insight into when or if they will kill again, as well as informing definition criteria of what constitutes a serial killer as opposed to mass or spree killing. Research in this area typically analyses aggregate, large-scale data; however, this can often miss the idiosyncratic, specific details that are needed in real-word cases. To provide a more detailed account, an in-depth case study approach was taken to analyse the behaviours of Dennis Rader and Lonnie Franklin Jr., two well-known American serial killers, throughout their criminal career and identify patterns in their dormancy periods between murders. The analysis highlights that trophy-taking, the use of letters to communicate with the public, and offending-orientated fantasy may increase the length of a cooling-off period by suppressing homicidal urges. In contrast, the need for homicidal control may influence the effectiveness of such suppressing factors over time. The present research suggests that life-events can influence intervals between murders, even acting as a catalyst at times, which may help legal decision making.
... Much has been surmised about the components of the serial murder definition since those early days (Yaksic, 2019a) but there is still no universal agreement as to what constitutes serial murder (Petee & Jarvis, 2000). The existing definition is fraught with pitfalls (Adjorlolo & Chan, 2014;Egger, 1984;McNamara & Morton, 2004;Yaksic, 2018) as various subtypes of offenders are included in research cohorts, such as organized crime members (Dietz, 1986), murderous health care workers, parents who kill their children, professional assassins and persons who kill spouses or lovers (Keeney and Heide, 1994), terrorists, outlaws, pirates, gang members, genocidal perpetrators (Lester and White (2012), witness elimination killers, robbery homicides (Osborne & Salfati, 2015), drug dealers, and doctors who prescribe an abundance of pain killers that lead to many deaths. Yaksic (2019b) argues that spree killers and serial homicide offenders (SHOs) are no longer dissimilar enough to warrant separate classification as they have converged into one cohort. ...
... The "cooling-off period" is theoretically used to separate SHOs from other murderers who kill in response to situational factors, convenience, survival and conflict resolution and not as a significant feature of their lifestyle (Yaksic, 2018). Of the few endeavors to look critically at the "coolingoff period", Osborne and Salfati (2015) argue that these intervals are crucial in defining serial homicide. Others (Douglas, Burgess, Burgess, & Ressler, 2013;Shanafelt & Pino, 2014;Yaksic, 2015;2019b) interpret this descriptor as a timeworn concept held over from a time when little was understood about SHOs given that serial murderers often think about killing during periods of down time and do not fully disengage from the process of killing. ...
... Lange (1999), for instance, introduced the idea that circumstances in the life of the offender influence the length of these intervals but specifically how this occurs remains unknown. SHOs also have the capacity to be distracted by other opportunities and those with longer timespans may be committing other crimes (Osborne & Salfati, 2015). Given the short period between the intervals of some SHOs, it is possible that they may never truly "cool off". ...
The “cooling-off period”, or inter-murder interval, has been used to differentiate between serial, spree, and mass murderers for decades. The present research examines the utility of this concept by studying the distribution of 2837 inter-murder intervals for 1012 American serial homicide offenders using data from the Consolidated Serial Homicide Offender Database. The distribution is smooth, following a power law in the region of 10–10,000 days. The power law is cut off in the region when inter-murder intervals become comparable with the length of human life. Otherwise there is no characteristic scale in the distribution. The decades long inter-murder intervals are not anomalies, but rare events described by the power-law distribution and therefore should not be looked upon with suspicion. This study found there to be no characteristic spree or serial homicide offender interval, only a monotonous smooth distribution lacking any features. This suggests that there is only a quantitative difference between serial and spree killers which represent merely different aspects of the same phenomenon.
... The most recent definition of serial murder has described the cooling-off period thus: "the murders are committed as discrete event(s) by the same person(s) over a period of time" (Adjorlolo & Chan, 2014, p. 490). As a result, new notions of short (less than two weeks) or long (more than two weeks, months, or even years) intervals between murders have become accepted in interpretations of serial murder (Osborne & Salfati, 2015; Schlesinger, Ramirez, Tusa, Jarvis, & Erdberg, 2017). ...
... Others have argued, however, that this psychological explanation is too abstract and have, instead, proposed other functions of this period of time. For example, Osborne and Salfati (2015) claimed that the geographical preference and selection of the victim or social involvement of the murderer influence the intervals between the murders (Greswell & Hollin, 1994;Hickey, 2002). ...
... Thus far, there is no statistical baseline or empirical research that clearly shows which factors directly influences the length of the cooling-off period. On the other hand, the cooling-off period has been found to be universal, thus proving that it has some latent function (Osborne & Salfati, 2015), in other words, it either enables or facilitates the next murder (Douglas et al., 2006;Douglas et al., 1986;Edelstein, 2014;Homes & Holmes, 1998;Levin & Fox, 2014;Morton & Hilts, 2008). ...
Theory and empirical research in criminology have paid less attention to intermittency in offending, that is, the brief lapses and sporadic episodes of crime that occur at sometimes unpredictable intervals (Piquero, 2004). This is mainly due to the problem of defining this phenomenon in a common operational way that can be tested empirically. This has thus led to its abandonment in most contemporary definitions of serial murder (Osborn & Salfati, 2014). Most up-to-date definitions have recognized the fact that serial murders are committed as discrete events (Adjorlolo & Chan, 2014). While psychological, sociological, and geographical theories of serial murder can be used to explain cooling-off periods, none of these theories have, thus far, been used in an empirical study. This article examines the phenomenon of cooling-off periods in relation to serial murder. Although definitions of serial murder have changed over the years, there is a consensus that between every two murders there must be a cooling-off period (Homant & Kennedy, 2014; Morton & McNamara, 2005). Unlike previous research, our study, which is based on the Encyclopedia of Serial Killers (Newton, 2005) found that the longest cooling-off period is between the first and the third murders (i.e., a series). We offer some theoretical psychological explanations for this pattern, although we were unable to study it empirically. We conclude that it is less important how different scholars define cooling-off periods; the important thing is that this phenomenon exists and has meaning for understanding, profiling, and even forecasting the time of the next murder.
... Cluff, Hunter, and Hinch (1997) observed that analysts have reduced the pool of research subjects by neglecting certain types of killers. Recent research from Osborne and Salfati (2015) shows that adhering to a more inclusive definition holds advantages. The Federal Bureau of Investigation (FBI) currently employs the broad two victim definition as it encompasses the full gamut of serial murderers by not referencing underlying motivation, behavior or psychological characteristics (Brantley & Kosky, 2005). ...
... Although it is impossible to discern the degree to which serial murderers remain entrenched in their killing lifestyle, many continue to utilize a temporal element as part of their exclusion criteria or to make distinctions between potentially similar serial offenders. Osborne and Salfati (2015) advise experts to discard 'cooling off' and re-conceptualize the concept into time intervals. Adjorlolo and Chan (2014) maintain that the continued use of the temporal distinction has restricted the utility of the current serial murder definition as these intervals could be less than one day. ...
... That spree and serial murderers should continue to be stratified separately is disputed since the 'cooling off period' is now characterized as a historical artifact (Douglas, Burgess, Burgess, & Ressler, 2013). Osborne and Salfati (2015) conclude that spree and serial homicide may not be distinguishable, including eight occasions of oneday time intervals and one series that lasted only three days in their data. ...
Conducting systematic research on serial homicide is complicated by variations in definition, sample size, data sources and collection procedures. This review will identify the challenges of utilizing data to study serial homicide and propose new methods to address these limitations. Almost three decades ago, Kiger (1990) highlighted the limitations of employing then existing data to study the social problem of serial murder and called for the creation of new sources to allow for quantitative assessments that used empirical data. In response, serial homicide researchers – previously operating in ‘information silos’ – contributed information to the ‘Serial Homicide Expertise and Information Sharing Collaborative’ to build a comprehensive record of serial homicide offending in partnership with the ‘Radford/FGCU Serial Killer Database Project’. Providing serial homicide data in an open access format empowers users to increase data reliability by interacting with the information to supply edits and corrections. Statistical evidence generated from the data enables analysts to disprove ingrained myths and stereotypes about serial murderers using valid data. Impaneled experts applied the Modified Delphi Technique and proposed adopting the broad term ‘multiple-event murderer’ to counter some institutionalized definitional differences. The exploration of creating a dashboard to track instances of serial homicide alongside further study of serial offenders committing revenge murders, witness elimination and robbery homicides, organized crime, contract and gang killings is recommended.
... On an individual level, offender's choices regarding the crime, such as the level of preparation, victim type, killing method, interaction with the victim, and body contribute to a murder series' longevity disposal (Beauregard & Martineau, 2016;Quinet, 2011;Reale & Beauregard, 2019). On a societal level, the murderer's homicide series can be influenced by routine events (e.g., daily activities) (Osborne & Salfati, 2015), location (e.g., geographic factors) (DeFronzo et al., 2007), and social controls (e.g., employment and romantic attachments) (Liem, 2013;Osborne & Salfati, 2015). Studies have also shown that situational circumstances (e.g., degraded evidence, improper police practices, and lack of investigative skills or inaction) have profound effects on the duration of the murderer's homicide series (Balemba et al., 2014;Brookman et al., 2019;James & Beauregard, 2020;James & Proulx, 2016;LePard, Demers, Langan, & Rossmo, 2015;Reale & Beauregard, 2019). ...
... On an individual level, offender's choices regarding the crime, such as the level of preparation, victim type, killing method, interaction with the victim, and body contribute to a murder series' longevity disposal (Beauregard & Martineau, 2016;Quinet, 2011;Reale & Beauregard, 2019). On a societal level, the murderer's homicide series can be influenced by routine events (e.g., daily activities) (Osborne & Salfati, 2015), location (e.g., geographic factors) (DeFronzo et al., 2007), and social controls (e.g., employment and romantic attachments) (Liem, 2013;Osborne & Salfati, 2015). Studies have also shown that situational circumstances (e.g., degraded evidence, improper police practices, and lack of investigative skills or inaction) have profound effects on the duration of the murderer's homicide series (Balemba et al., 2014;Brookman et al., 2019;James & Beauregard, 2020;James & Proulx, 2016;LePard, Demers, Langan, & Rossmo, 2015;Reale & Beauregard, 2019). ...
... On an individual level, offender's choices regarding the crime, such as the level of preparation, victim type, killing method, interaction with the victim, and body contribute to a murder series' longevity disposal (Beauregard & Martineau, 2016;Quinet, 2011;Reale & Beauregard, 2019). On a societal level, the murderer's homicide series can be influenced by routine events (e.g., daily activities) (Osborne & Salfati, 2015), location (e.g., geographic factors) (DeFronzo et al., 2007), and social controls (e.g., employment and romantic attachments) (Liem, 2013;Osborne & Salfati, 2015). Studies have also shown that situational circumstances (e.g., degraded evidence, improper police practices, and lack of investigative skills or inaction) have profound effects on the duration of the murderer's homicide series (Balemba et al., 2014;Brookman et al., 2019;James & Beauregard, 2020;James & Proulx, 2016;LePard, Demers, Langan, & Rossmo, 2015;Reale & Beauregard, 2019). ...
... On an individual level, offender's choices regarding the crime, such as the level of preparation, victim type, killing method, interaction with the victim, and body contribute to a murder series' longevity disposal (Beauregard & Martineau, 2016;Quinet, 2011;Reale & Beauregard, 2019). On a societal level, the murderer's homicide series can be influenced by routine events (e.g., daily activities) (Osborne & Salfati, 2015), location (e.g., geographic factors) (DeFronzo et al., 2007), and social controls (e.g., employment and romantic attachments) (Liem, 2013;Osborne & Salfati, 2015). Studies have also shown that situational circumstances (e.g., degraded evidence, improper police practices, and lack of investigative skills or inaction) have profound effects on the duration of the murderer's homicide series (Balemba et al., 2014;Brookman et al., 2019;James & Beauregard, 2020;James & Proulx, 2016;LePard, Demers, Langan, & Rossmo, 2015;Reale & Beauregard, 2019). ...
Purpose
The duration of time that the serial offender remains free in the community to commit murders may be seen as a direct measure of their longevity; a sign of their success. The aim of this study is to predict the duration of the serial homicide series by examining the factors that contribute to the length of time a serial murderer is able to remain free of police detection.
Methods
Generalized estimating equations with a negative binomial link function were used to examine factors predicting the duration of series in a sample of 1258 serial murder cases.
Results
Results showed that offenders' criminal history, race (i.e., White and Hispanic), and victims of minority backgrounds significantly predicted longer duration in their murder series. A combination of multiple killing methods and atypical methods also predicted longer murder series, while the moving of the victim's body predicted shorter duration in the series.
Conclusions
This study builds upon the serial homicide literature, particularly the duration of the series. Results from this study help inform investigative efforts in serial homicide cases.
... The variable length of a MHO's career is impacted by many factors that also influence the span of intervals between killings. The presence or absence of police surveillance, personality differences, marriage, the influence of a partner, or geographic factors (Lange, 1999), and daily activities (Osborne and Salfati, 2014) can impact the MHO's engagement with deviant behavior. Location (DeFronzo et al., 2007), social controls such as employment, attachments (Liem, 2013;Osborne and Salfati, 2014), personal choices such as body disposal, victim type, and crime scene actions (Quinet, 2011;Reale and Beauregard, 2019;James and Beauregard, 2020), outside contextual circumstances such as the thoroughness of the investigation (LePard et al., 2015;James and Beauregard, 2020). ...
... The presence or absence of police surveillance, personality differences, marriage, the influence of a partner, or geographic factors (Lange, 1999), and daily activities (Osborne and Salfati, 2014) can impact the MHO's engagement with deviant behavior. Location (DeFronzo et al., 2007), social controls such as employment, attachments (Liem, 2013;Osborne and Salfati, 2014), personal choices such as body disposal, victim type, and crime scene actions (Quinet, 2011;Reale and Beauregard, 2019;James and Beauregard, 2020), outside contextual circumstances such as the thoroughness of the investigation (LePard et al., 2015;James and Beauregard, 2020). ...
Relying on a sample of 1,394 US-based multiple homicide offenders (MHOs), we study the duration of the careers of this extremely violent category of offenders through Kaplan-Meier estimation and Cox Proportional Hazard regression. We investigate the characteristics of such careers in terms of length and we provide an inferential analysis investigating correlates of career duration. The models indicate that females, MHOs employing multiple methods, younger MHOs and MHOs that acted in more than one US state have higher odds of longer careers. Conversely, those offending with a partner and those targeting victims from a single sexual group have higher probability of shorter careers.
... The agreed upon definition of serial murder from the symposium was "the unlawful killing of two or more victims by the same offenders in separate events" (Morton & Hilts, 2008, p. 12). This is still the FBI's current definition of serial murder, but the definition has been criticized for painting serial murder too broadly and various definitions of serial murder are still found in the academic literature since the symposium (Adjorlolo & Chan, 2014;Haggerty, 2009;Hickey, 2016;Osborne & Salfati, 2015;Santtila et al., 2008). ...
... What separates one event from another event has been referred to as a "cooling-off period." How much time a cooling-off period consists of has been debated, but the idea is that the killer's life returns to an interval of normalcy before the killer claims a new victim (Kraemer et al., 2004;Osborne & Salfati, 2015). In the present study, almost one out of every four (24.5%) killers did not appear to enter into any cooling-off periods. ...
Serial murder is a rare phenomenon, yet an incredibly popular topic as evidenced by the availability of various types of entertainment media about serial murder. The present study provides a content analysis of serial murder in film utilizing 50 randomly selected films covering a 35-year period (1980-2015). Data were coded for 53 fictional killers and 362 victims to generate profiles of the typical serial killer and their victims in film. The results are discussed in relation to real-world data on serial murder to describe the accuracies and inaccuracies of the portrayal of serial murder in film.
... This notwithstanding, some researchers continue to emphasize specific characteristics such as cooling-off period (Homant & Kennedy, 2014;Morton & McNamara, 2005), sexual motives (Kraemer et al., 2004), and no prior relationship between offender and victim (Haggerty, 2009) as being central to conceptualizing and understanding serial murder. Meanwhile, difficulties in operationalizing, for instance "cooling-off period" (Homant & Kennedy, 2014;Osborne & Salfati, 2014) have led to its abandonment in most contemporary definitions of serial murder (Osborne & Salfati, 2014). Recognizing the challenges posed by "cooling-off period" some researchers argued that "the main point is that the first killing has temporarily satisfied whatever motives are driving the killer, and the subsequent killings are part of a separate sequence of behaviors" (Homant & Kennedy, 2014). ...
... This notwithstanding, some researchers continue to emphasize specific characteristics such as cooling-off period (Homant & Kennedy, 2014;Morton & McNamara, 2005), sexual motives (Kraemer et al., 2004), and no prior relationship between offender and victim (Haggerty, 2009) as being central to conceptualizing and understanding serial murder. Meanwhile, difficulties in operationalizing, for instance "cooling-off period" (Homant & Kennedy, 2014;Osborne & Salfati, 2014) have led to its abandonment in most contemporary definitions of serial murder (Osborne & Salfati, 2014). Recognizing the challenges posed by "cooling-off period" some researchers argued that "the main point is that the first killing has temporarily satisfied whatever motives are driving the killer, and the subsequent killings are part of a separate sequence of behaviors" (Homant & Kennedy, 2014). ...
Over the years, researchers and law enforcement professionals have tried to achieve uniformity in the use of the term “serial murder,” but such efforts have rather proved futile. Endeavors aimed at achieving a consensus on the definition of serial murder have potentiated its precarious applications. Though the term continues to remain elusive, ambiguous and amorphous in the literature, recent efforts are suggestive of a trend towards the attainment of a standardized definition of serial murder. However, a review of both current research and legal definitions of serial murder revealed some discrepancies in how the term is defined. Built upon Skrapec’s (2001) definition, the current paper aims to revisit several key definitional issues and to propose a more comprehensive serial murder definition with three key elements: (1) Two or more forensic linked murders with or without a revealed intention of committing additional murder, (2) the murders are committed as discrete event(s) by the same person(s) over a period of time, and (3) where the primary motive is personal gratification.
... Both definitions emphasize the importance of linking separate crime scenes by physical evidence, including cases where no suspect has been identified, rather than accepting offenders' claims for murders that have not been solved. However, research has failed to support a significant "cooling off" period or time segments between murders [18,19], thus the time dimension outlined by Adjorlolo and Chan, that murders are committed "over a period of time", appears to be more precise in that regard [1]. ...
Historically, serial homicide has been defined in various ways by experts. Recently, there have been renewed efforts to arrive at a consensus definition, yet these efforts have not yet been resolved. At the heart of the controversy appears to be the prioritization of either qualitative definitional features, such as offenders’ intentions and motives, or more observable quantitative features, specifically a minimum threshold of completed murders. The present technical note briefly summarizes this controversy before considering new empirical and theoretical research developments. These developments support a definition that includes a three-victim minimum threshold of forensically linked murderers by the same person(s), occurring in separate events over time, wherein a primary motive is often personal gratification (leisure experience).
... Serial homicide is often defined as the killing of two or more people in separate events by the same offender (Federal Bureau of Investigation 2008), with some scholars including hostile intent (Harbort and Mokros 2001) or the concept of destructive aggression (Knight 2006). The Federal Bureau of Investigation's (FBI) (2008) definition of serial homicide also removed "cooling-off periods" (time between homicides), which some scholars argue is still an essential aspect of defining serial homicide (Osborne and Salfati 2015;Sutton and Keatley 2021). In one typology, serial homicide includes planning (premeditative intent); in another, it is a violent response to frustration or physical aggression toward a perceived threat with the intention of death for the victim. ...
Violence in serial homicide is a complex and dynamic part of an offender’s behavior. This chapter explores how aggressive and violent behavior is a part of serial homicide and the escalation of aggression to violence. The organized/disorganized dichotomy of serial killers and reactive and proactive aggression is used to help explain different types of aggression and how they may be exhibited during the commission of a crime. The proposed aggression–violence continuum conceptualizes aggression on a behavior continuum for offending behaviors and helps to visualize how violent an offender may be. The violence portion of the continuum is then further broken down into the tiers of serial violence that demonstrate an ascending level of violence and presents the escalating nature of serial homicide.
... Although serial and spree murderers were integrated together after attendees of a symposium deemed the separate classifications to be of little use (Morton and Hilts, 2008), some authors continue to stratify offenders using temporal parameters even though spree homicide may not be distinct enough to classify separately (Osborne and Salfati, 2015). Schlesinger et al. (2017) found support for such claims since a sizeable number of serial murderers killed in a rapid-sequence manner either all in one spree, or in one or two clusters. ...
Serial murder has had a storied history which has complicated society’s understanding of the topic. Much of what is known about serial murder by the general public has been generalized, filtered through the realm of entertainment, and converted into myths and stereotypes. Half a century after the term was reconceptualized, basic concepts – such as how to properly define serial murder and what constitutes a series – are still a matter of great debate. For the purposes of this article serial murder is defined as the unlawful killing of two or more victims by the same individual(s) over a period of more than 14 days. Better data and efforts to collaborate more widely have recently led to discoveries that have shown serial murder to be the result of a multifaceted, complex process involving the offender’s unique socialization, experiences, and fantasies that develop over the course of their maturation. It is now believed that the majority of serial murderers are not criminal masterminds but rather ‘street smart’ individuals, employed in often menial jobs, who accumulate life-altering issues, and come to embrace a self-centered lifestyle punctuated by manipulation, shallow emotion, impulsivity, and pathological lying. They need to work serial killing into a life occupied by other tasks and objectives such as family, work, and community obligations. Data has shown that modern serial murderers tend to be local undereducated men of average intelligence, who are often convicted of intimate partner violence, are lucky to escape apprehension, and propelled forward by a deep sense of entitlement, fragile masculinity, easy access to firearms, and a nonchalant attitude toward using murder to attain their goals. There has been a decline in serial murder globally, but an increase in cultural fascination. The height of serial murder has come and gone because the situational factors that contributed to the success of serial murderers from previous eras have been indirectly addressed by our heavily surveilled society, the proliferation of tracking technology, a better prepared and connected police force, and an aware and vigilant public. Globally there are similarities between the racial, cultural, and ethnic characteristics of serial murderers.
... Forensic evidence linking these homicides should be plentiful as youthful offenders rarely take countermeasures to ensure that crime scenes are sanitized . Serial offenders do not always complete their intended crimes and as such all shootings within at least the past six months should be analyzed for potential linkages (Osborne and Salfati, 2015). The offender may contact law enforcement to confess if the pressure to capture him does not dissipate. ...
The purpose of this article is to improve the use of evidence-based practice and research utilization in the offender profiling process. The use of offender profiling has been met with increasing resistance given its exaggerated accuracy. The “Investigative Journalist/Expert Field Micro Task Force” model, a collaborative method that incorporates offender profiling and is designed to address unresolved serial homicides, is introduced and evaluated alongside recommendations on attaining adherence.
The model was field tested in 17 instances. The measures used by the Federal Bureau of Investigation to gauge the usefulness of their case consultations, whether their input helped catch the offender, offer new leads, move the case forward, provide new avenues or give new ideas, were used to evaluate the model.
The model established likely patterns of serial murder activity among strangulations of women in Chicago, Cleveland, and Panama and resulted in convictions of suspects in Louisiana and Kansas City. This model is valuable when used to parse modern-day offenders from those who committed unresolved homicides as the latter display different behaviors that can make investigations difficult endeavors. Results from the field tests mirror those from the literature in that profiling alone did not result in the capture of serial killers. Instead, profiling was used in conjunction with other efforts and mainly as a means to keep the investigation moving forward.
Unresolved homicides are at a point of crisis and represent a significant but largely unaddressed societal problem. The success of this model may compel law enforcement to restore faith in offender profiling.
... This was an unpopular edict as serial and spree killers had traditionally been separated into distinct classes by chronology, location and motive. Some asked if serial and spree killings are truly different crimes (Salfati et al., 2006) and combined these cohorts together (Culhane et al., 2014;DeLisi and Scherer, 2006;Gurian, 2009) as they may not be distinguishable (Osborne and Salfati, 2015) given that serial murderers often kill in a "spree-like" or rapid sequence manner over a few days' or weeks' time (Schlesinger et al., 2017). This paper aims to demonstrate where rapid sequence homicide offenders (RSHOs) fit in the broader scheme of criminal offenders and reexamine the spree/serial killer categorical structures given the recent preponderance of the understudied RSHO, formerly named "spree killers" now defined as those that kill more than one victim within a 14-day period. ...
Purpose
Rapid sequence homicide offenders (RSHOs), formerly spree killers, are an understudied population due to the confusion surrounding their classification in relation to serial murderers. The paper aims to discuss this issue.
Design/methodology/approach
An exploratory, comparative analysis of 56 RSHOs and 60 serial murderers was conducted on US-based data from 2014 to 2018 derived from the Consolidated Serial Homicide Offender Database to determine similarities and differences between the cohorts.
Findings
RSHOs and serial murderers are similar in that they often kill their victims using a singular method, have limited mobility, kill a similar number of victims both known and unknown to them and are both supremely motivated by domestic anger. There is an inverse relationship between serial murderers and RSHOs: as one group increases in prevalence the other decreases.
Practical implications
In order to divert men into more pro-social activities, attention must be dedicated to increasing mental health services that provide them with the tools to diffuse their hatred and couple that with effective gun control strategies and ways to enhance the compromised anger management skills of a generation of volatile men.
Originality/value
Academicians have been hesitant to juxtapose these offenders but based this conclusion on surface-level differences. A reimagining of these categorical structures is needed. The once clear delineation between these cohorts may continue to shrink and synchronize until one subsumes the other.
... For those who have clearly established prerequisite time frames, the minimum length ranges from 24 hours (Kraemer et al., 2004) to over 30 days (Holmes & Holmes, 2010) to months and years (Bartol & Bartol, 2008). Osborne and Salfati (2015) found that the minimum time interval between kills ranged from one to over a thousand days, suggesting that the cooling-off period must be better conceptualized in the future. This document is copyrighted by the American Psychological Association or one of its allied publishers. ...
Objective: Despite substantial interest in the topic, there remains no consensus on the definition of serial killing, particularly in terms of the minimum victim count. Whereas most scholars had settled on either a three-victim or four-victim minimum, the Federal Bureau of Investigation (FBI) decided a decade ago to lower the threshold down to just two murders. In this article we empirically examine the effect of lowering the threshold on the statistical profile of serial homicide and suggest what appears to be the optimal threshold based on distinguishing attributes. Method: A series of multinomial logistic regression analyses is used to compare two-victim, three-victim and four-victim offenders (as well as those who claimed even larger victim counts) on a variety of traits generally considered stereotypical of the serial killer. Results: Two-victim offenders differ significantly from all other serial killers in terms of motive, partnership, and crime scene behaviors, and arguably should not be pooled into a single population. Moreover, those who have slain between three and seven victims differ significantly in terms of these same characteristics from those who have killed eight or more. Conclusions: A minimum victim threshold of at least three should be used, separating potential or would-be serial killers from those who are characterized by more extreme levels of violent behavior. Furthermore, the population of serial killers can be subdivided into typical offenders claiming three to seven victims and their far more deadly counterparts with eight or more murders. (PsycINFO Database Record
... For the purposes of this study, the term partnered is used instead of team when describing groups (two or more) of offenders; this term is more reflective of the criminal responsibility incurred by offenders who kill together, particularly with respect to mixed sex groups in which the woman's role is often mitigated (see, for example, Ajzenstadt, 2009;Myers, Gooch, & Meloy, 2005;Scott, 2005;Warr, 2002). With respect to the definition of serial murder used in this study, the temporal element eliminates cases of mass murder (in which multiple victims are killed in one place at one time) and the debated "cooling off period" (Osborne & Salfati, 2015). A minimum of two victims also allows for a broader definition, which is less likely to exclude cases of solo female serial murderers, and includes cases that are typically listed with other serial murderers with higher victim counts (Farrell et al., 2011;Jenkins, 1994). ...
Empirical research on serial murder is limited due to the lack of consensus on a definition, the continued use of primarily descriptive statistics, and linkage to popular culture depictions. These limitations also inhibit our understanding of these offenders and affect credibility in the field of research. Therefore, this comprehensive overview of a sample of 508 cases (738 total offenders, including partnered groups of two or more offenders) provides analyses of solo male, solo female, and partnered serial killers to elucidate statistical differences and similarities in offending and adjudication patterns among the three groups. This analysis of serial homicide offenders not only supports previous research on offending patterns present in the serial homicide literature but also reveals that empirically based analyses can enhance our understanding beyond traditional case studies and descriptive statistics. Further research based on these empirical analyses can aid in the development of more accurate classifications and definitions of serial murderers.
© The Author(s) 2015.
... The dearth of studies on this concept has allowed for additional confusion about its use as a criterion for serial homicide. Osborne & Salfati (2014) explored the idea of cooling-off periods in serial homicide in the US and determined that at the first stages of analysis it be more aptly termed, time interval between homicides, and should not include the clinical/psychological component. By taking the subjective non-measurable motivational component out, and keeping the more objective measurable element of 'time,' aptly renamed time interval, a usable criterion was formed. ...
There is an abundance of literature on serial homicide from a Western perspective that outlines operational definitions, types of offenders and how they prey upon their victims. However, currently, there is a lack of studies that compare serial homicide in different countries. The current study aims to give an overview of the demographics of serial homicide offenders and victims in South Africa and compare these to the demographics of offenders and victims from other currently available empirical studies of other countries. The sample consisted of 33 out of the total 54 solved series in South Africa between 1936–2007, which includes a total of 33 offenders, 302 victims, and 254 crime scenes. Results of the sample as a whole showed that South African serial homicide offenders are similar to offenders in other countries in terms of their actions at the crime scene and victim choice, with some notable exceptions. Additional analysis looked at the offender's consistency of targeting certain types of victims across their homicide series in comparison with the patterns of serial homicide offenders in other countries. Copyright © 2014 John Wiley & Sons, Ltd.
Serial murder has had a storied history which has complicated society’s understanding of the topic. Much of what is known about serial murder by the general public has been generalized, filtered through the realm of entertainment, and converted into myths and stereotypes. Half a century after the term was reconceptualized, basic concepts – such as how to properly define serial murder and what constitutes a series – are still a matter of great debate. For the purposes of this article serial murder is defined as the unlawful killing of two or more victims by the same individual(s) over a period of more than 14 days. Better data and efforts to collaborate more widely have recently led to discoveries that have shown serial murder to be the result of a multifaceted, complex process involving the offender’s unique socialization, experiences, and fantasies that develop over the course of their maturation. It is now believed that the majority of serial murderers are not criminal masterminds but rather ‘street smart’ individuals, employed in often menial jobs, who accumulate life-altering issues, and come to embrace a self-centered lifestyle punctuated by manipulation, shallow emotion, impulsivity, and pathological lying. They need to work serial killing into a life occupied by other tasks and objectives such as family, work, and community obligations. Data has shown that modern serial murderers tend to be local undereducated men of average intelligence, who are often convicted of intimate partner violence, are lucky to escape apprehension, and propelled forward by a deep sense of entitlement, fragile masculinity, easy access to firearms, and a nonchalant attitude toward using murder to attain their goals. There has been a decline in serial murder globally, but an increase in cultural fascination. The height of serial murder has come and gone because the situational factors that contributed to the success of serial murderers from previous eras have been indirectly addressed by our heavily surveilled society, the proliferation of tracking technology, a better prepared and connected police force, and an aware and vigilant public. Globally there are similarities between the racial, cultural, and ethnic characteristics of serial murderers.
The present study reports offender, victim and offence characteristics of the entire population of known serial homicide offenders identified in Italy between 1848 and 2019 (59 offenders, 244 victims, of whom 50.4% were men, and 21.7% were sex workers). We found that most of the offenders (72.4%) had a personality disorder. The offenders’ age during their series was 35.1 (SD = 11.3) years, on average. Sexual elements were found in 28.4% of the crime scenes. The median time interval between homicides was 2.8 months. Also, we investigated the consistency of the offence characteristics over the series and found significant correlations between the offence characteristics between a previous and the subsequent homicide.
Child sexual abuse and the criminogenesis thereof are notably not perpetrated in isolation from physical and emotional abuse – although empirical evidence suggests that the most profound impact thereof revolves around a desire to escape (as a coping mechanism) into a world of deviant sexual fantasy, rape and murder. The article explores a phenomenological case study analysis of a serial rapist and murderer from birth to early adulthood, prior to incarceration – and it depicts an existence driven by fatal sadistic sexual desires, hate and lethal intent. The researchers conducted face-to-face interviews with the participant comprising of three one-hour interviews, with the aid of a semi-structured interview schedule. The study highlighted the need for a proactive response in rendering psychosocial services to the abused child.
Relying on a sample of 1,381 US-based multiple homicide offenders (MHOs), we study the duration of the careers of this extremely violent category of offenders through Kaplan–Meier estimation and Cox Proportional Hazard regression. We investigate the characteristics of such careers in terms of length and we provide an inferential analysis investigating correlates of career duration. The models indicate that MHOs employing multiple methods, younger MHOs and MHOs that acted in more than one US state have higher odds of longer careers. When controlling for career-based attributes, female MHOs are also correlated with longer careers.
Quite possibly, the first application of geographic analysis to identify and characterise the spatial behaviour of the offender concerning the crime scene was developed in 1980 by Milton Newton. Although previous studies have used Newton and Swoope's geoforensic process (Kent, 2009, Essays on the integration of anisotropic landscapes within contemporary geographic profiling models [LSU doctoral dissertations]; Leitner et al., 2007, Police Practice and Research, 8[4], 359–370) to verify the effectiveness of the algorithm, there are, to our knowledge, no investigations that have validated the procedure with cases of serial murderers. The main objective of the study is to analyse a sample of 41 serial killers with a minimum number of six crimes and to evaluate the method proposed by Newton (1988, Geographical discovery of the residence of an unknown dispersing localized serial murder). The results confirm only Newton's first assumption in which after the fifth crime in the series, the estimated ‘haven’ is close to the actual ‘haven’, ruling out that the search area becomes progressively smaller and that the ‘haven’ is located in the search area.
This represents one of several sections of "A Bibliography Related to Crime Scene Interpretation with Emphases in Geotaphonomic and Forensic Archaeological Field Techniques, Nineteenth Edition" (The complete bibliography is also included at ResearchGate.net.). This is the most recent edition of a bibliography containing resources for multiple areas of crime scene, and particularly outdoor crime scene, investigations. It replaces the prior edition and contains approximately 10,000 additional citations. As an ongoing project, additional references, as encountered, will be added to future editions.
The impact of one’s culture on daily activities is inescapable. That impact, whether conscious or not, must in some ways extend to the commission of crimes as well as victim reactions. The compiler witnessed this in the investigation of the abduction and murder of a young Bosnian girl who had resettled in the United States with more than 8,000 other refugees from the Balkan Wars of the early 1990s. The ease with which her neo-Nazi murderer was able to enter the homes of the Bosnian refugees, and ultimately kidnap this victim, was partly the result of the cultural experiences of the victimized families who feared law enforcement in their home country and so were reluctant to report the preadtor who introduced himself into their community as a health inspector. This category includes citations beyond those about death rituals and includes references about criminal psychology, cultural studies, and forensic psychiatry. A greater understanding of the psychological and cultural motivation subjects might have in committing crimes will impact approaches to searching for, and processing, evidence. One need not be a behavioral scientist or criminal profiler to realize that a subject diagnosed with paranoia might dispose of a victim in a manner different than a sociopath. An example of cultural influence in the selection of a victim’s disposal site is the case of Jeremiah James Bringsplenty. Accounts of this 1992 case included that of the abuse and murder of Jeremiah by family acquaintances who were babysitting the infant in his Clarksville, Tennessee home. Both the victim and the subjects were of Native American ancestry. The subjects left Tennessee for the Rosebud Reservation in South Dakota with plans to bury Jeremiah near relatives. Because of decomposition, however, they were forced to stop outside Lincoln, Nebraska to bury the remains. This section also contains references valuable for investigators interviewing subjects and witnesses. This category and “General and Cultural Anthropology of Death” overlap to some degree. The examples or accounts examined in the resources within this section involve a spectrum of physical traumas which might befall victims of homicide or suicide. For that reason, the reader/research should also look in Taphonomy-Trauma for related citations.
(3305 citations)
We study the distribution of 2,837 inter-murder intervals (cooling off periods) for 1,012 American serial killers. The distribution is smooth, following a power law in the region of 10-10,000 days. The power law cuts off where inter-murder intervals become comparable with the length of human life. Otherwise there is no other characteristic scale in the distribution. In particular, we do not see any characteristic spree-killer interval or serial-killer interval, but only a monotonous smooth distribution lacking any features. This suggests that there is only a quantitative difference between serial killers and spree-killers, representing different samples generated by the same underlying phenomenon. The over decade long inter-murder intervals are not anomalies, but rare events described by the same power-law distribution and therefore should not necessarily be looked upon with suspicion, as has been done in a recent case involving a serial killer dubbed as the "Grim Sleeper." This large-scale study supports the conclusions of a previous study, involving three prolific serial killers, and the associated neural net model, which can explain the observed power law distribution.
Although it has been suggested among both forensic experts and a small number of leisure scientists that serial murder may be a form of recreational leisure, such suggestions remain largely unexplored both theoretically and empirically. Given the absence of scholarship on this possibility, this project explored and analyzed the structure and function of leisure activities within an unusual case (Dennis Rader) of serial murder. A thorough analysis of relevant case documents confirmed that serial murder itself can be experienced by the killer as a form of recreational leisure with the potential for optimal psychological experience (flow), and that various leisure activities may function in specific ways within the serial murder process. An unexpected finding in this case was that leisure, specifically project-based leisure, served to structure specific killings. Findings provide valuable new insights for forensics behavioral experts that may be used to guide future research.
Years ago, a small handful of leisure scholars suggested that serial murder may be a form of leisure. However, to date this possibility remains virtually unexplored. This article draws from recent research to share reflections and rich, new insights on how leisure science may provide important contributions to serial homicide researchers and law enforcement personnel. At the same time, exploring such intersections offers leisure scholars new ways of understanding familiar concepts and theories. Possibilities for future research are discussed.
A review of the literature on multiple murder reveals little systematic research on this phenomenon despite widespread media interest and figures indicating that over 3 per cent of homicide victims in England and Wales die in incidents of multiple homicide. Difficulties in both defining multiple murder and estimating its prevalance are noted, although these can be seen as essential steps towards the formulation of a comprehensive psychological model of this type of crime. A review of the literature indicates that fantasy rehearsal of murderous and sadistic acts is commonly reported in this group, and stresses the importance of examining environmental factors that could elicit and control violent behaviour. It is concluded that further research is required in three areas: (1) detection and recognition of a multiple crime perpetrator from crime scene evidence; (2) identification and recognition of risk factors within imprisoned and clinical populations; (3) identification of the treatment needs and the appropriate disposal of these offenders.
Analyzing the natural histories of two samples of boys that differ dramatically in childhood delinquency, we test a model of crime and deviance over the life course. The first hypothesis is that childhood antisocial behavior predicts problems in adult development across a wide variety of dimensions. Second, we argue that social bonds in adulthood--to work and family--explain changes in crime and deviance over the life span. The longitudinal data were reconstructed from the Gluecks' classic study of delinquent and non-delinquent males from childhood to age 32. Childhood delinquency is linked to adult crime, alcohol abuse, general deviance, economic dependency, educational failure, unemployment, divorce, and even charges in the military. Despite this continuity, job stability and strong marital attachment in adulthood inhibit adult criminal and deviant behavior. The results support a model of informal social control that recognizes both stability and change in antisocial behavior over the life course.
In this paper we present a "routine activity approach" for analyzing crime rate trends and cycles. Rather than emphasizing the characteristics of offenders, with this approach we concentrate upon the circumstances in which they carry out predatory criminal acts. Most criminal acts require convergence in space and time of likely offenders, suitable targets and the absence of capable guardians against crime. Human ecological theory facilitates an investigation into the way in which social structure produces this convergence, hence allowing illegal activities to feed upon the legal activities of everyday life. In particular, we hypothesize that the dispersion of activities away from households and families increases the opportunity for crime and thus generates higher crime rates. A variety of data is presented in support of the hypothesis, which helps explain crime rate trends in the United States 1947-1974 as a byproduct of changes in such variables as labor force participation and single-adult households.
There were many expressions of shock and surprise voiced in the media in 2002 when the “D.C. Sniper” turned out to be two Black males. Two of the stereotypes surrounding serial killers are that they are almost always White males and that African American males are barely represented in their ranks. In a sample of 413 serial killers operating in the United States from 1945 to mid-2004, it was found that 90 were African American. Relative to the African American proportion of the population across that time period, African Americans were overrepresented in the ranks of serial killers by a factor of about 2. Possible reasons why so few African American serial killers are known to the public are explored.
This paper considers a suspect prioritization technique and tests its validity using a sample of commercial armed robbery offences from St John's, Newfoundland, Canada. The proposed technique is empirically grounded in criminal careers and journey‐to‐crime research. Suspects with a previous criminal history are selected and ranked in ascending order by the distance they live from the location of the crime in question, with the nearest suspect given highest priority. Effectiveness is measured by the percentage of ranked suspects that needs to be searched before the offender is identified. Results show that 65% of the robbers were identified in the top 10% of ranked suspects. Limitations and proposed refinements are discussed in terms of future prioritization strategies and policing research.
Many studies have shown that distributions of the distances that offenders travel in the commission of their offences are typically characterised by a decay function. However, there are few empirical comparisons of the different mathematical functions which may characterise such distributions. Further, there has been little consideration of what different forms of function may reflect about the underlying factors and psychological processes governing this aspect of the journey to crime. With the increasing use of geographical profiling systems which incorporate decay functions into their calculations, it is particularly of value to explore the most appropriate mathematics for describing the frequencies of crime journeys and to determine the impact of different decay functions on the effectiveness of a geographical profiling system. A two-stage study was therefore carried out using data derived from 96 US serial killers. In the first stage three different decay functions were examined, in terms of the extent to which they fitted a distribution of the distances travelled to offend for the sample; logarithmic, in accordance with Steven's ‘Power Law’ for distance estimation; negative exponential as an estimate based on the ‘friction’ generated by journeys; and quadratic, which reflects key principles found from journey to crime research. A ‘control’ function, simple negative linear, was also tested against the data. It was found the logarithmic function provided the closest approximation to the journey to crime distances of offenders in the present sample (R2 = 0.81, p < 0.001), suggesting that distance estimations may be an important part of the explanation for the length of the crime trips that offenders make. In the second stage, all four functions were utilised within a geographical profiling system (Dragnet) and their impact on the search cost for locating an offender established for the whole sample. In general it was found that the search cost function, which relates the proportion of the sample to the search cost, was positively monotonic with a distinct change in gradients around 58% of the sample, indicating that the software was producing useful results in the majority of cases. However, although the logarithmic function produced the best results overall, and the linear function the worst, as hypothesised, no significant differences between the search costs were found when each of the different functions was utilised. The implications for the robustness of the software and the possible influence of the low precision of the raw data are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Since the 1970s, investigative profilers at the FBI's Behavioral Science Unit (now part of the National Center for the Analysis of Violent Crime) have been assisting local, state, and federal agencies in narrowing investigations by providing criminal personality profiles. An attempt is now being made to describe this criminal-profile-generating process. A series of five overlapping stages lead to the sixth stage, or the goal of apprehension of the offender: (1) profiling inputs, (2) decision-process models, (3) crime assessment, (4) the criminal profile, (5) investigation, and (6) apprehension. Two key feedback filters in the process are: (a) achieving congruence with the evidence, with decision models, and with investigation recommendations, and (b) the addition of new evidence.
A rational choice theory approach was used to analyze the offense behavior of serial sex offenders. Qualitative data were
obtained through the descriptions of the crimes provided by 69 serial sex offenders who were incarcerated in a Correctional
Service of Canada institution. Based on the offenders’ accounts, a descriptive model specific to the hunting process was identified.
This model contained the following nine phases: offender and victim routine activities, choice of hunting ground, victim selection,
method of approach, attack location choice, method to bring the victim to the crime site, crime location choice, method to
commit the crime, and the victim release location choice. The model is discussed according to existing research on serial
sex offenders and environmental criminology. Implications for clinical practice, crime prevention, offender profiling, and
future studies are discussed.
A cusp catastrophe model was fitted to the time series of kill dates of eleven serial murderers, using no additional external information. As predicted, this model provided a superior fit (Median R2 =0.67) to the data than competing linear models (Median R2 =0.43 and 0.22). Moreover, a single equation could be identified which was moderately effective (R2 =0.53) in predicting the changes in the intervals between successive killings across individual killers. All time series showed evidence for the existence of a cyclic underlying process, although distinctions could be made depending on whether the phase portrait showed an attractor, a repellor, or a pulse type pattern. Finally, using a neural net approach it proved possible to distinguish pairs of serial killers solely based on properties of their time series. These findings are best explained by biological theories which assume that the cyclic nature of serial murder is the result of the successive domination of opposing forces.
The last several decades have seen increased research attention to the subject of serial murder. Unfortunately, an empirical understanding of serial homicide continues to be impeded by difficulties in establishing a working definition for serial murder. Current definitions for serial homicide tend to focus on frequency and timing of homicide behaviors, and thus leave some confusion as to which groups of individuals should be included under the heading of serial murders. This article suggests alterations to the definition of serial murder, which focus not only on frequency and timing of homicide behaviors, but also on the motivation and context of those behaviors.
A model of individual sexual offenders' spatial activity was developed based upon 45 British male sexual assaulters who had committed at least two assaults. For each offender a separate map was produced indicating the spatial locations of his offences and residence. A Marauder model and a Commuter model of offender's spatial behaviour was proposed. As an elaboration of the Marauder model, the Circle and Range hypotheses were tested against the sample of offenders. Results of the study support the Marauder model showing that most of the sample (87%) move out from their home base in a region around that base to carry out their attacks. The antithetical Commuter model was not supported within the sample. The Circle and Range hypotheses were supported demonstrating that offenders operate within a distinct offence region (in 91% of cases) and that the distance they travel to offend correlates directly with distances between offences (r = 0.93, p < 0.001). The findings clearly indicate that there is a basis for a model of offence venue choice by individuals within the sample. The present study supports the value of a theory of domocentricity within offenders' lives and offers potential applicability to the solving of crimes.
Mass, spree, and serial homicide
- A W Burgess
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Serial murder: Multi-disciplinary perspectives for investigators
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Geographic profiling
- D K Rossmo
Rossmo, D. K. (2000). Geographic profiling. Boca Raton, FL: CRC Press.
The Homicide Profiling Index (HPI): A tool for measurements of crime scene behaviors, victim characteristics, and offender characteristics
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Offender profiling: Psychological and methodological issues of testing for behavioural consistency
- C G Salfati
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Serial and spree homicide: Different crimes or all serial crimes? Presentation at American Society of Criminology Conference
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