A Comprehensive Assessment of Leakage, Threats, Public Reporting, and Responses to Reports among Public, Family, and Felony Mass Shootings

This study provides a comprehensive assessment of leakage, threats, public reporting, and criminal justice responses to reports among all U.S. mass shootings in which four or more victims were killed from 2000 to 2023 ( N = 483). Based on available evidence, our findings indicate that leakage and threats both appear more common among public mass shooters than family or felony shooters. Criminal propensity, “cry for help,” and attention-seeking theories may explain why perpetrators often reveal their violent intent. The public appears to report leakage and threats less consistently than the criminal justice system responds to such reports; however, important opportunities for improvement exist in both areas. Multiple factors help explain variation in reporting rates, but public uncertainty about individuals’ dangerousness may be the greatest barrier, rather than fears of retribution. Based on these findings and others, we offer recommendations for improving mass shooting prevention.