The research team drew on data from the Centers for Disease Control and Prevention’s National Violent Death Reporting System, a surveillance program that links death certificates, medical examiner findings, and law enforcement reports to build a richer picture of violent deaths than any single source can provide. From 2018 to 2023, the system captured 115,873 homicide deaths. The investigators sorted these into three categories: single-victim homicides, multi-victim homicides involving two or three victims, and mass homicides defined as events with four or more victims killed, excluding the perpetrator. This classification allowed them to compare the three groups across victim demographics, suspect characteristics, weapons used, locations, and the circumstances that precipitated each event.

The scale of the numbers alone is sobering. The overwhelming majority of victims, 90.5 percent or 104,858 people, died in single-victim homicides. Yet nearly one in twelve victims lost their lives in multi-victim events: 10,123 people were killed across 4,789 incidents, representing 8.7 percent of all homicide deaths in the dataset. That proportion is higher than what an earlier study using the same reporting system found for 2003 to 2017. The authors caution that the increase may reflect the expanded geographic coverage of the reporting system as more states joined over time, or it may signal genuine shifts in national homicide patterns, which rose during the corresponding period. Mass homicides, defined as events with four or more fatalities, accounted for less than 1 percent of deaths but claimed 892 lives across 178 incidents, with individual cases ranging from 4 to 51 victims.

Where these killings happened varied in striking ways. Mass and multi-victim homicides frequently occurred in homes, while single-victim homicides most often took place in public settings such as streets or vehicles. This geographic split carries practical implications: residential violence may be less visible to bystanders and less accessible to conventional street-level interventions, while public-location killings may demand different environmental and policing strategies. The finding that multi-victim events cluster in domestic settings aligns with the study’s central observation about intimate partner violence as a precipitating circumstance.

Demographic patterns were largely consistent with previous research, but the contrasts between categories were pronounced. Mass homicides more often involved non-Hispanic White victims and children, whereas single- and multi-victim homicides more often involved non-Hispanic Black victims and suspects who were acquaintances or friends of those killed. Nearly half of the victims in both multi-victim and single-victim homicides were aged 18 to 34 years, compared with 29.8 percent of mass homicide victims in that age range. Across all three categories, both victims and suspects were primarily male, underscoring the persistent gendered character of lethal violence in the United States.

The racial and ethnic distributions of victims and suspects differed notably by category. The highest proportion of mass homicide victims were non-Hispanic White, at 39.7 percent, while the highest proportions of multi-victim and single-victim homicide victims were non-Hispanic Black, at 47.8 percent and 54.8 percent respectively. Among suspects, non-Hispanic White individuals accounted for 32.2 percent and non-Hispanic Black individuals for 30.1 percent of mass homicide suspects, while in multi-victim and single-victim homicides the highest proportions of suspects were non-Hispanic Black, at 37.6 percent and 36.8 percent respectively. These distributions, the study suggests, reflect the distinct social contexts in which different types of homicide unfold rather than a single uniform phenomenon.

Firearms dominated as the method of injury across every category, reinforcing the central role of guns in American lethal violence. Firearms were involved in 75.8 percent of mass homicides, 86.3 percent of multi-victim homicides, and 76.4 percent of single-victim homicides. The consistency of this finding across victim counts suggests that any firearm-related prevention measure could theoretically affect all categories of homicide, although the study’s authors emphasize that tailored approaches remain essential given the differing circumstances surrounding each type of event.

The precipitating circumstances revealed perhaps the most actionable patterns. Intimate partner violence was a common precipitator in nearly one-third of mass homicides, at 31.0 percent, and was also frequently associated with multi-victim homicides at 16.9 percent and single-victim homicides at 15.0 percent. Family relationship problems and a recent or impending crisis within the preceding two weeks were common circumstances in mass and multi-victim killings. For multi-victim and single-victim homicides, arguments and criminal activity were frequent precipitators. Taken together, these findings indicate that relationship conflict and acute personal crises are not marginal factors but central drivers of lethal violence across the spectrum, from a single death to the deadliest mass events.

The study’s authors argue that these differences are key to developing tailored prevention strategies. A policy aimed at reducing argument-driven street violence, for example, may require community-based conflict mediation and violence interruption programs, while addressing intimate partner violence as a precursor to mass casualty events may call for stronger risk assessment, lethal violence screening in domestic violence services, and coordinated responses when families show signs of acute crisis. The identification of a two-week crisis window before many mass and multi-victim killings suggests a potential point of intervention, though the study stops short of prescribing specific policies.

Patrick S. Sullivan, DVM, PhD, of Emory University, Editor-in-Chief of Annals of Epidemiology, underscored the value of the underlying data infrastructure in a statement accompanying the publication. “This analysis is a reminder of what public data systems make possible,” he said. “By linking death certificates, medical examiner findings, and law enforcement reports, the National Violent Death Reporting System lets us see that homicide is not one problem but several — each with its own affected populations and precipitating circumstances. The findings of this study offer important guideposts for the policies and interventions most likely to reduce these tragic and preventable outcomes.” As US homicide rates continue to fluctuate, the study provides a granular evidence base suggesting that treating homicide as a single public health problem obscures the very distinctions that effective prevention depends on.

Subject of Research: Patterns and precipitating circumstances of single-victim, multi-victim, and mass homicides in the United States

Article Title: Study reveals distinct patterns across single-, multi-, and mass homicides

Article References: Study reveals distinct patterns across single-, multi-, and mass homicides. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: homicide, mass homicide, intimate partner violence, public health, National Violent Death Reporting System, firearms, epidemiology, violence prevention, CDC, Annals of Epidemiology, victim demographics, precipitating circumstances