By Felber J. Arroyave, Alexander M. Petersen, Jeffrey Jenkins & Rafael Hurtado

Illicit wildlife trafficking poses a threat to the conservation of species and ecosystems, and represents a fundamental source of biodiversity loss, alongside climate change and large-scale land degradation. Despite the seriousness of this issue, little is known about various socio-cultural demand sources underlying trafficking networks, for example the forthright consumption of endangered species in different cultural contexts. Our study illustrates how wildlife trafficking represents a wicked problem at the intersection of criminal enforcement, cultural heritage and environmental systems management. As with similar network-based crimes, institutions are frequently ineffective at curbing wildlife trafficking, partly due to the lack of information detailing activities within illicit trading networks. To address this shortcoming, we leverage official government records documenting the illegal trade of reptiles in Colombia. As such, our study contributes to the understanding of how and why wildlife trafficking persists across robust trafficking networks, which are conduits for a broader range of black-market goods. Leveraging geo-spatial data, we construct a multiplex representation of wildlife trafficking networks, which facilitates identifying network properties that are signatures of strategic trafficker behavior. In particular, our results indicate that traffickers’ actions are constrained by spatial and market customs, a result which is apparent only within an integrated multiplex representation. Characteristic levels of sub-network coupling further indicate that traffickers strategically leverage knowledge of the entire system. We argue that this multiplex representation is essential for prioritizing crime enforcement strategies aimed at disrupting robust trade networks, thereby enhancing the effectiveness and resources allocation of institutions charged with curbing illicit trafficking. We develop a generalizable model of multiplex criminal trade networks suitable for communicating with policy makers and practitioners, thereby facilitating rapid translation into public policy and environmental conservation efforts.

Applied Network Science volume 5, Article number: 20 (2020)

By Tanya Wyatt, Daan van Uhm & Angus Nurse

Historically, the poaching of wildlife was portrayed as a small-scale local activity in which only small numbers of wildlife would be smuggled illegally by collectors or opportunists. Nowadays, this image has changed: criminal networks are believed to be highly involved in wildlife trafficking, which has become a significant area of illicit activity. Even though wildlife trafficking has become accepted as a major area of crime and an important topic and criminologists have examined a variety of illegal wildlife markets, research that specifically focuses on the involvement of different criminal networks and their specific nature is lacking. The concept of a ‘criminal network’ or ‘serious organized crime’ is amorphous – getting used interchangeably and describes all crime that is structured rather than solely reflecting crime that fits within normative definitions of ‘organized’ crime. In reality, criminal networks are diverse. As such, we propose categories of criminal networks that are evidenced in the literature and within our own fieldwork: (1) organized crime groups (2) corporate crime groups and (3) disorganized criminal networks. Whereas there are instances when these groups act alone, this article will (also) discuss the overlap and interaction that occurs between our proposed categories and discuss the complicated nature of the involved criminal networks as well as predictions as to the future of these networks.

Trends in Organized Crime (2020) 23:350–366

By Meredith L. Gore , Robert Mwinyihali , Luc Mayet Gavinet Duclair, Makaya Baku-Bumb , etc.

Urban wildmeat consumption can contribute to significant declines in wildlife populations, ecosystem function, and food insecurity security. Describing types of individuals involved in illegal urban wildmeat trafficking can help distinguish ordinary citizens from members of criminal organizations and urban vs. rural dimensions of the activity. This research aimed to: (1) create and apply a typology for urban wildmeat traffickers and sellers; and (2) explore linkages between types of urban wildmeat traffickers and sellers. We used focus groups with experts in the Republic of the Congo, February 2019 (N = 2, n = 7–10) to achieve objectives and focused on pangolins, great apes, and dwarf crocodiles. Participants generated risk rankings for each species, typology and city; data was encoded and indexed. Results illustrate heterogeneity in actors involved in the illegal supply chain. Business sideliner and trading charity trafficker types were associated with the highest total risk to wildlife trafficking. A similar pattern of divergence was detected for seller typologies; hidden and casual sellers were associated with the greatest total risk in Pointe Noire and Brazzaville, respectively. Differentiating but not stove piping stakeholders involved in urban wildmeat trafficking will help clarify stages of illegal supply chains as well and promote thinking about new sectors to involve in interventions and solutions, particularly in urban ecosystems thought to be outside the scope to wildlife crime.

Global Ecology and Conservation. Volume 27, June 2021, e01557

By Michelle Anagnostou

The intensified illegal trade of wildlife has contributed to the unsustainable decline of wildlife populations, the destabilization of ecosystems, and threatens economic development and human security. Though often lacking empirical evidence, convergence theory has emerged recently as a topic of interest among researchers, practitioners, and the media to explain the growing overlap of criminal activities in an increasingly globalized world. In this paper, I explain the interdisciplinary theoretical foundations for the interconnectivity of criminal networks, including connections between illegal wildlife trade networks and non-state armed groups. I also outline and discuss various perspectives on the convergence of the illegal wildlife trade with other organized crime activities. I conclude by highlighting the urgent need for a better understanding of the role of the organized criminal groups involved in the illegal wildlife trade, and of how these groups converge with other types of criminal activities. The policy implications of filling in this knowledge gap are twofold: firstly, understanding how criminal networks converge can facilitate the implementation of more effective law enforcement and investigations that target high-profile offenders, as opposed to focusing on low-level poachers; and secondly, this understanding can foster more cooperation across agencies and jurisdictions to address multiple crime types and crime in convergence settings

Environmental Challenges. Volume 5, December 2021, 100222

By Earth League International and John Jay College of Criminal Justice

Environmental crime convergence, the focal point of this report, poses an imminent threat to our planet’s delicate ecosystems. To address this urgent issue, ELI, and John Jay College present ELI’s revolutionary 4-Type Environmental Crime Convergence paradigm to comprehensively understand and combat the intricate web of transnational organized crime operations that perpetuate environmental degradation.

The foundation of this report is built upon the fieldwork and intelligence analysis of ELI’s investigators and crime analysts, who have gathered first-hand evidence of Environmental Crime Convergence directly from some of the world’s most notorious environmental criminals and their networks. Drawing on years of investigative fieldwork in the Americas, Europe, Africa, and Asia, over two dozen case studies have emerged from ELI’s work as primary sources of data.

This report highlights five (5) case studies of the transnational criminal networks in Latin America identified by ELI that illustrate the convergence of environmental and wildlife crime with other serious crimes and expose the severity of the issue at a global scale.

Los Angeles: Earth League International, 2023. 83p.

By Jack Norton, Stephen Jones, Bea Halbach-Singh, Jasmine Heiss

When people are arrested and charged for activities they are forced to engage in to survive—such as driving without a license or sleeping outside—poverty becomes criminalized. In these cases, being poor is essentially made illegal. In collaboration with Free Hearts—an organization led by formerly incarcerated women—Vera researchers explain how poverty has been criminalized across Tennessee and what this means for people who live in communities in the state. The effects of the criminalization of poverty are compounded through the collection of money bail; additional fines, fees, and costs; and barriers to housing, transportation, education, and employment. With deep dives into several counties across Tennessee, the report shows how incarceration and policing are related to other systems that both punish and exacerbate poverty in the state. The report outlines actionable steps that can be taken now to build toward a vision of safety that includes all Tennesseans.

New York: Vera Institute of Justice, 2022. 58p.

By Michael Jendrykea, , Stephen C. McClure

From time to time the popular media draws attention to hate crimes and hate groups, evoking images of NaziGermany and the rise of fascism. The geographic association between hate groups and hate crimes is uncertain. In this research we ask whether hate crimes are co-located and correlated to the presence of hate groups to explore a potential association between these two phenomena. Publicly available point level data on hate crimes and hate groups collected by the Southern Poverty Law Center (SPLC) were aggregated to unitary framework of hexagonal grid cells of a Discrete Global Grid System (DGGS) at multiple scales for consistent analysis. We explore the effects of proximity by interpreting a co-location map, deploying a Geographically Weighted Regression (GWR) for count data, and apply a Spatial Lag Model (SLM) at multiple scales, to ascertain the effects of the size of the aggregation units on the relationship between hate groups and hate crimes. Controlled or uncontrolled for spatial dependence, at all scales, the Spatial Lag Model (SLM) shows that an average of 39.5% of the hate crimes was correlated with hate groups. These results are consistent with the existing research but show that in most instances spatial dependence was present, regardless of the size of the aggregation unit or the distance to neighboring cells. Our future research will consider additional racial, economic and social variables using a DGGS.

Applied Geography. Volume 111, October 2019, 102072

By Gary Sweeten and Matthew Larson

This report describes a project that had the main goal of developing a broad, nationally representative understanding of how often statutory rape occurs in the U.S., who the victims and perpetrators are, how self-reported estimates compare to estimates from law enforcement data, and whether short- and/or long-term consequences exist and if they do, what the consequences might be. In order to accomplish that goal, the project had four specific objectives: to estimate nationally representative rates of statutory rape victimization and perpetration using the National Longitudinal Survey of Youth 1997 (NLSY97); to assess situational differences between first sexual experiences that are statutory rape compared to those that are not; to estimate the likelihood of women’s statutory rape victimization being reported to police, using data from the National Incident-Based Reporting System (NIBRS); and to assess the short- and long-term consequences of statutory rape victimization, based on the nature and characteristics of relationships as well as on the age differences between victims and perpetrators. The authors provide a breakdown of their research design, methods, analytical and data analysis techniques, results and findings for the four objectives, research limitations, artifacts, datasets generated, and dissemination activities.

Washington, DC: National Institute of Justice Research and Evaluation on Violence Against Women, 2023. 57p.

By Linda M. Williams, April Pattavina, Alison C. Cares, and Nan D. Stein

Given the considerable changes in federal legislation and the pressing requirements that colleges and universities develop policies and practices that meet the needs of victims and of those accused of sexual assault, there is a critical need to document and understand how colleges are handling these demands and coordinating campus approaches to investigation and adjudication of sexual assaults. In 2015, the National Institute of Justice (NIJ) funded a project to commence January 2016, designed to examine the variations in policies and practices and understand more about challenges and emerging best practices. The research reported here was designed to identify the range and scope of policies and practices related to the investigation and adjudication of sexual assault on college campuses in the U.S. The Wellesley Centers for Women (WCW) with the assistance of an expert panel of advisory board members has documented and classified the current landscape (the breadth and differences) of campus approaches to investigations and adjudication of sexual assault. Our first step, informed by a victim-centered focus, was a web-based search of a randomly selected sample of four year colleges and universities (Institutions of Higher Education, IHEs) on policies and practices for investigation and adjudication of sexual assault reports. This web search was a systematic broadbased environmental scan designed to examine the policies and practices promulgated to the public and, most importantly, made available to students by IHEs. This environmental scan was followed by interviews with Title IX coordinators to develop a clearer understanding of the challenges and successes of these policies.

Washington, DC: U.S. National Institute of Justice, 2020. 91p.

By The Victorian Law Reform Commission

This report contains 45 recommendations for stalking law reform. They aim to improve the ways that the justice system treats people who have experienced stalking in a non-family violence context.

The report recommends that victims should have easier access to financial and practical support, such as technology to prevent cyberstalking. Victims should be supported by independent advocates to guide them through every stage, from reporting the stalking activity to accessing support services and any court actions.

The report also recommends improvements to the personal safety intervention order (PSIO) system. The system is currently swamped, so non-family violence stalking matters do not receive the attention they need. The VLRC recommends developing guidance on how to identify and prioritise stalking cases.

Another recommendation calls for the Crimes Act to be amended to make the stalking offence clearer and easier to apply.

Melbourne: The Commission, 2022. 238p.

By John Coyne and Teagan Westendorf

THis report helps develop an understanding of the quantum of profits being made and where in the value chain they occur. Australians spent approximately A$5.8 billion on methamphetamine and A$470 million on heroin in FY 2019.

Approximately A$1,216,806,017 was paid to international wholesalers overseas for the amphetamine and heroin that was smuggled into Australia in that year. The profit that remained in Australia’s economy was about A$5,012,150,000. Those funds are undermining Australia’s public health and distorting our economy daily, and ultimately funding drug cartels and traffickers in Southeast Asia.

One key takeaway from the figures presented in this report is that the Australian drug trade is large and growing. Despite the best efforts of law enforcement agencies, methamphetamine and heroin use has been increasing by up to 17% year on year. Falling prices in Southeast Asia are likely to keep pushing that number up, while drug prices and purity in Australia remain relatively stable.

Canberra: Australian Strategic Policy Institute, 2021. 40p.

By Shannon Brennan and Benjamin Mazowita

 Between 2011 and 2016, 2,362 people in British Columbia had a fatal overdose from illicit drugs, with 332 occurring in Surrey specifically. The majority of individuals who died of an illicit drug overdose in British Columbia (66%) and specifically in the City of Surrey (64%) had no contact with police in the 24 months preceding their overdose death. For the purposes of this study, a contact with the police is defined as an official intervention, where the individual was identified by police as a person accused of a criminal incident.  Overall, most of the decedents (66%) held some form of employment in at least one of the five years preceding their overdose death, regardless of any contact with police. That said, decedents who had a formal contact with the police were less likely to have experienced consistent employment over the 5 years. One in five (20%) decedents who had contact with police were employed in each of the 5 years prior to their fatal overdose, compared to 29% of decedents who did not have contact.  More than two-thirds (68%) of decedents who had contact with police had also received social assistance benefits in the 5 years prior to their death, a proportion that was significantly higher than their counterparts who had no contact with police (55%).  In general, most decedents were not hospitalized in the year before their death. This held true for both those who had contact with police (72%) and those who did not (75%). The remaining one in four decedents were hospitalized at least once in the year preceding their death. The most common reasons for hospitalization among decedents in the year before their death besides opioid poisonings were in connection to substance use related disorders and mental health conditions.  While the majority of decedents never came into contact with police, among those who did (34%), many did so multiple times. Overall, 15% of decedents in British Columbia and 16% of decedents in the City of Surrey had three or more formal contacts with police in the 24 months preceding their overdose death.  Overall, among decedents who had a contact with police, 33% in British Columbia (and 24% in the City of Surrey) had a fatal overdose in the 90 days following their last contact with police. These findings indicate the need for timely interventions.  The majority of decedents who came into contact with police prior to their fatal overdose did so for a non-violent crime: 83% of police contacts were for non-violent offences whereas the remaining 17% involved violent offences. Shoplifting of items valued at $5,000 or under was the most common reason decedents came into contact with police in the 24 months prior to their death. Aside from property offences and, more specifically, shoplifting, offences against the administration of justice were also among the most common reasons decedents came into contact with police. These offences were also highly represented among the decedent cohort, relative to the province as a whole.  In line with their police interactions, most of the decedents who appeared in a criminal court within the 2 years preceding their overdose death did so in relation to property offences and offences against the administration of justice. Specifically, cases involving theft, breach of probation and failure to comply with an order were among the most prevalent

Ottawa: Statistics Canada, 2019. 18p.

By Benjamin Ferri and Lia Yin

Does inequality lead to more crime? We develop a new model that articulates how Poverty (the lower tail of the earnings distribution) and Earnings (the upper tail) enter into equilibrium crime rates. In our model, individuals in Poverty have less to lose in the context of criminal punishment, so are less averse to committing crimes in general. The presence of high Earnings (therefore things worth stealing) heightens the expected gain to offenders per crime - but specifically in terms of financial gain, not emotional gain. We estimate our model on a comprehensive panel of U.S. Commuting Zones (1980-2016), deploying novel Shift-Share instruments to correct for reverse causality (of crime on the earnings distribution). Corroborating our hypothesis, we find that high Earnings plays a much larger role in driving crimes that yield financial gain to the offender (various forms of theft) than it does for crimes of emotional gain; while Poverty is a driving force equally across both types of crime. In each case, not accounting for reverse causality would underestimate both effects, often by more than double.

Unpublished paper, 2022. 50p.

By The San Francisco Domestic Violence Death Review Team

This Domestic Violence Death Review Team (DVDRT) Pilot was created under the provisions of the California Penal Code 11163.3, in order to fulfill a commitment to review domestic violence-related fatalities, strengthen system policies and procedures, and identify prevention strategies that will reduce future incidents of domestic violence-related injuries and deaths. The DVDRT fulfills a need in San Francisco, as the city lacks staffing for a dedicated Death Review Team. This DVDRT Pilot provides an overview of the DVDRT process and methodology for their investigation into a murder case from October 2014; it lays out details of the event as well as DVDRT’s analysis of evidence and case-related data, and notes the aspects of the event that the DVDRT focused on include: computer-aided dispatch (CAD) systems; real-time assistance for police officers in crime scene evaluation; broad interaction and information gathering; the ability of the police department to enforce physical separation when physical violence has occurred; custodial treatment of intoxicated individuals; real-time assistance for police from domestic violence advocates; providing closure and well-being assistance to 911 call-takers and dispatchers; availability and use of body-worn video (BWV) cameras; and in multiple responses to the victim’s address, the efficient and thorough transfer of information to later-responding officers.

San Francisco: The Review Team, 2023. 57p.

By Dyna Ibrahim

Intimate partner violence is a serious issue which continues to negatively affect victims long after the abuse has ended (McGarryet al. 2017; Campbell et al. 2002). This complex issue, broadly, involves physical, sexual, emotional and financial abuse, between current and former partners (Northcott 2012; Coker et al. 2002). While, presently, there are no legislated offences in the Canadian Criminal Code specifically related to intimate partner violence, Criminal Code offences of general application, such as physical and sexual assault, criminalize intimate partner violence. There are Criminal Code provisions which consider the fact that an offender abused their intimate partner an aggravating factor for sentencing purposes (Heslop et al. 2016). Even with ample tools, programs and policies at the national, provincial and community levels dedicated to reducing and preventing intimate partner violence in Canada (McCormick and Irwin 2016; Gill and Fitch 2016; Hilton and Eke 2016; Beaupré 2015; Benoit et al. 2014; Northcott 2012), there remains much to be done in the area. In particular, while many studies (Simpson 2018; Calton et al. 2016; Parry and O’Neal 2015; Perreault 2015; Sinha 2013; Beauchamp 2004) have shown that people who identify as lesbian, gay or bisexual are at increased risk for victimization in general, there is little quantitative research on the extent and nature of violence which takes place within same-sex intimate relationships in Canada (Langenderfer-Magruder et al. 2016; Ristock 2011). Related studies suggest that individuals in same-sex partnerships who experience intimate partner violence may face special barriers when it comes to disclosing their experiences or seeking help. For example, the threat of exposing one’s sexual orientation to others and fears about other people’s misguided beliefs that abuse among same-sex partners is mutual have been identified as obstacles which are often unique to victims in same-sex relationships. Moreover, individuals who are in same-sex intimate partnerships are vulnerable to “minority stress”, the psychological pressure from being a member of a minority group that is stigmatized or marginalized. Additionally, previous negative experiences such as discrimination and harassment, and perceptions or anticipation of stigma and negative stereotypes—all of which are particularly prevalent among individuals in same-sex partnerships—may lead to beliefs that these experiences will occur in various other facets of life (Calton et al. 2016; Baker et al. 2015; Edwards et al. 2015; Parry and O’Neal 2015; Benoit et al. 2014; Overstreet and Quinn 2013; Brown 2008; Rostosky et al. 2007). All these factors can reduce the reporting of violence to police and help-seeking among this share of the population. This Juristat article aims to help shed light on the nature of violence which is experienced within same-sex intimate partnerships. Using data from the Incident-based Uniform Crime Reporting Survey, this article will examine, for the first time, the characteristics of police-reported violence among same-sex intimate partners in Canada. In order to increase the scope of analysis and allow for a more detailed examination of incident, victim and accused characteristics, data from 2009 to 2017 are pooled.1 In addition, data from the most recent (2014) General Social Survey on Canadians’ Safety (Victimization) is included in order to examine the self-reported experiences of various forms of intimate partner violence whether it was reported to the police or not. While the focus of this article is violence among individuals in same-sex relationships, information on gender-diverse individuals is not included. Research has shown that people who identify as transgender or non-gender conforming are especially vulnerable to violence in general, as well as violence within an intimate partner setting (Langenderfer-Magruder et al. 2016; Mitchell-Brody et al. 2010; Stotzer 2009). However, the data sources used in this article do not allow for the examination of the experiences of individuals belonging to this segment of the population.

Ottawa: Statistics Canada, 2019. 29p.

By Claire Ferguson and Freya McLachlan

Links between IPF and homicide concealment have been observed but not explained. We theorize IPF perpetrators use concealment to continue coercively controlling investigators, children, courts and finances post-IPF. We compare abuse in the relationship and surrounding IPF in five diverse cases. Facilitated by concealment, offenders use versatile, subtle and overt tactics to extend control post-IPF. They capitalize on opportunities for concealment and regaining control, sometimes without other benefits. Tactics are akin to those employed previously, aligning with the power and control wheel. Concealment allows offenders to dominate the death narrative and assists with remaining unaccountable.

Feminist Criminology 2023, Vol. 0(0) 1–23

By Jens Ludwig

The purpose of this project, a collaboration between the University of Chicago Crime Lab and the New York City Police Department, was to develop and test a novel machine-learning based statistical model to predict the risk of domestic-violence victimization to improve intervention in cases at high risk for violence. The field intervention with the NYPD was launched in July 2017. NYPD command maintains a list of high-priority individuals who are thought to be at risk for serious domestic assault. Individuals on this list receive regular home visits from one of the local NYPD’s Domestic Violence Officers (DVOs) to reduce the risk of future victimization. The researchers believe that upon the completion and dissemination of this work, the results will be relevant to researchers and policymakers who are assessing ways to reduce domestic violence.

Washington, U.S. Department of Justice, Office of Research and Evaluation, National Institute of Justice, 2022. 11p.

By Kristine Denman, Callie Dorsey, Joel Robinson, Jenna Dole and Ashleigh Maus

The New Mexico Statistical Analysis Center received funding from the Bureau of Justice Statistics to study the case processing of domestic and non-domestic aggravated and sexual assault cases. Two primary research questions guide the study. First, it explores whether there are criminal justice disparities among aggravated assault and sexual assault cases involving domestic violence relative to cases not involving domestic violence. Second, it examines whether female defendants are treated differently than male defendants. Overall, we find that case processing outcomes for domestic assault are either the same or less serious than case processing outcomes for non-domestic assault. These findings differ from those found in a national study conducted by BJS, but are similar to other findings in New Mexico and elsewhere. We also find that male defendants generally have more serious case processing outcomes than female defendants, but this is moderated somewhat by domestic violence involvement. This report describes these findings. A summary report can be found in the “Fast Facts” section of our website.

Albuquerque: New Mexico Statistical Analysis Center, 2020. 37p.

By HM Inspectorate of Probation (UK)

The impact of domestic abuse is significant and far-reaching. An estimated 2.4 million adults were victims of domestic abuse across England and Wales last year, and one in seven children live with domestic abuse at some point in their childhood. Women are disproportionately affected by domestic abuse, with an estimated 1.7 million female victims last year. Those responsible for this abuse account for a very significant part of the Probation Service caseload, with approximately 30 percent of people on probation identified as current or previous perpetrators of domestic abuse. When we last inspected this topic in 2018, we reported that too many individuals were drifting through their sentences without being challenged or supported to change their abusive behaviours. Very concerningly, despite some positive developments in policy, little appears to have improved in practice, and in some respects, things have deteriorated. Only 28 per cent of the cases we inspected for this review had a sufficient assessment which analysed the risks of further domestic abuse, and only 23 per cent had been reviewed adequately to consider significant changes in the case. This is unacceptable and is leaving far too many potential victims at risk. People on probation can be offered a range of interventions aimed at helping them make positive changes in their lives and equipping them to have safe and healthy relationships. However, too few people gain access to these interventions; 45 percent of our case sample should have had access to an intervention but had not. In addition, there is insufficient monitoring of referral, take-up, and completion rates for interventions at a national level to understand the overall picture. It is unacceptable that requirements to undertake a domestic abuse perpetrator programme made as part of sentencing are not delivered, yet this happens in many cases. Staffing shortages in the Probation Service have led to reductions in expectations around minimum levels of contact with people on probation, partnership working, and the delivery of interventions. In domestic abuse cases, this has led to worrying deficits in the standard of sentence management. Probation staff demonstrate high levels of commitment to their work, often working well over their expected hours, but high caseloads often prohibit them from being able to complete meaningful work. In addition, recent changes in legislation through the Domestic Abuse Act 2021, such as the recognition of children affected by domestic abuse as victims in their own right, have not been incorporated into probation practice. More needs to be done to ensure that there is a shared understanding of roles and responsibilities among agencies working with domestic abuse, and that information is shared to safeguard victims

Manchester, UK: HM Inspectorate of Probation, 2023. 61p.

By Katherine A. Fowler, Rachel A. Leavitt, Carter J. Betz, Keming Yuan & Linda L. Dahlberg

Multi-victim homicides are a persistent public health problem confronting the United States. Previous research shows that homicide rates in the U.S. are approximately seven times higher than those of other high-income countries, driven by firearm homicide rates that are 25 times higher; 31% of public mass shootings in the world also occur in the U.S.. The purpose of this analysis is to examine the characteristics of mass, multiple, and single homicides to help identify prevention points that may lead to a reduction in different types of homicides.

We used all available years (2003–2017) and U.S. states/jurisdictions (35 states, the District of Columbia, and Puerto Rico) included in CDC’s National Violent Death Reporting System (NVDRS), a public health surveillance system which combines death certificate, coroner/medical examiner, and law enforcement reports into victim- and incident-level data on violent deaths. NVDRS includes up to 600 standard variables per incident; further information on types of mental illness among suspected perpetrators and incident resolution was qualitatively coded from case narratives. Data regarding number of persons nonfatally shot within incidents were cross-validated when possible with several other resources, including government reports and the Gun Violence Archive. Mass homicides (4+ victims), multiple homicides (2-3 victims) and single homicides were analyzed to assess group differences using Chi-square tests with Bonferroni-corrected post-hoc comparisons.

Results: Mass homicides more often had female, child, and non-Hispanic white victims than other homicide types. Compared with victims of other homicide types, victims of mass homicides were more often killed by strangers or someone else they did not know well, or by family members. More than a third were related to intimate partner violence. Approximately one-third of mass homicide perpetrators had suicidal thoughts/behaviors noted in the time leading up to the incident. Multi-victim homicides were more often perpetrated with semi-automatic firearms than single homicides. When accounting for non-fatally shot victims, over 4 times as many incidents could have resulted in mass homicide.

Conclusions: These findings underscore the important interconnections among multiple forms of violence. Primary prevention strategies addressing shared risk and protective factors are key to reducing these incidents.

Injury Epidemiology (2021) 8:49