Study: 86% of Mass Shooters Signal Intent Before Attacks
A new study found that nearly 86% of mass shooters communicated violent intentions before attacking — but those warning signs were scattered, making them hard to act on.
COLUMBUS, OHIO — Most people who carry out mass public shootings display observable warning signs well before an attack, but those signals are typically scattered among different people and institutions, making them hard to connect in time to prevent violence, according to a new study released by the Regional Gun Violence Research Consortium at the Rockefeller Institute of Government.
The nonpartisan public policy think tank analyzed a sample of 171 mass public shootings in the United States between 1999 and 2024, covering attacks at workplaces, schools and shopping malls. Researchers concluded that these events are rarely sudden or unpredictable.
Warning Signs Often Visible But Fragmented
Nearly 86% of perpetrators communicated violent thoughts or intentions to at least one other person before carrying out an attack, a behavior pattern researchers describe as “leakage.” Those disclosures typically occurred through in-person conversations or text messages, and were most often shared with people in the perpetrator’s immediate social circle, including friends, family members and coworkers.
On average, warning signs were spread across more than two different groups of observers, meaning no single person held a complete picture of the escalating threat, according to the report. Researchers describe the attacks not as spontaneous acts but as the result of cumulative stressors, concerning behaviors and communications of intent that, if connected, could have created opportunities for earlier intervention.
Stressors and Behavioral Patterns
The study found that perpetrators tended to experience multiple overlapping stressors rather than a single triggering event in the period leading up to an attack. These stressors, combined with escalating warning signs spread across different people and institutions, formed a pattern that researchers say could be identified if information were shared more effectively.
Because warning signs were distributed across friends, family, coworkers and institutions, no one individual was positioned to recognize the full scope of the threat. Researchers framed this fragmentation as a key challenge for prevention efforts, suggesting that better systems for connecting these dispersed signals could offer earlier intervention opportunities.
Implications for Prevention
The Rockefeller Institute of Government study points to the period before an attack as a window during which intervention may be possible, given that the vast majority of perpetrators communicate their intentions in some form. The report’s findings are based on analysis of shootings over a 25-year span, from 1999 through 2024, providing one of the broader looks at warning sign patterns across mass public shooting cases in the United States.
The Regional Gun Violence Research Consortium is housed at the Rockefeller Institute of Government, a nonpartisan public policy research organization. The full report is available through the institute’s website.
