From cartridge cases to spatial patterns: Leveraging NIBIN to identify near-repeat shootings in Detroit

This study uses ballistic evidence entered into the National Integrated Ballistic Information Network (NIBIN) to examine near-repeat shooting patterns in Detroit, Michigan, drawing on 5487 incidents involving the discharge of one or more firearms between January 2021 and October 2022. Conducted within the context of the Detroit Crime Gun Intelligence Center, our study captures a broad view of gun violence, integrates NIBIN linkages to advance understanding of the nature of gun violence, and extends analysis beyond dyads to multi-incident shooting chains. To this end, we applied the Knox test to identify near-repeat patterns and then grouped shooting incidents into chains based on their spatiotemporal proximity. We used multinomial and mixed-effects logistic regression to distinguish between the observed patterns. Our results show that gun violence in Detroit clusters tightly in space and time and is linked to high-risk places as well as circulating, multi-use crime guns. We discuss the implications of these findings for guiding law enforcement in developing integrated strategies that combine place-based and network-focused interventions to prevent and reduce gun violence in communities.