Evaluation of the Milwaukee Police Department’s Crime Gun Intelligence Center

By Christopher Koper | Heather Vovak | Brett Cowell 

This study presents an evaluation of the Crime Gun Intelligence Center (CGIC) initiative in Milwaukee conducted by a research partner team from the National Police Foundation and George Mason University. The report covers the operations and impacts of the CGIC program from 2014 through 2017. The first part of the report documents the CGIC program as it operated during the study period. The heart of the CGIC initiative involves systematic collection and analysis of ballistics evidence collected from both crime scenes and test fires of recovered firearms. This ballistics evidence is scanned into the National Integrated Ballistics Information Network (NIBIN) administered by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF). Scanning ballistics evidence into NIBIN enables analysts to compare images of ballistics evidence across cases nationwide to identify gun crimes that may have involved the same firearm (based on unique markings that firearms make on fired shell casings and bullets). This helps investigators to identify crimes that are likely to have been committed by the same offender or by offenders who used the same firearm. Teams of detectives, analysts, and other staff from MPD, ATF, and other partner agencies use these leads to prioritize, inform, and target gun crime investigations and prosecutions. The second part of the report presents three series of analyses conducted by the Milwaukee CGIC’s research partners to assess the potential and actual impacts of the CGIC initiative on gun-related investigations and gun crime in Milwaukee. All of these analyses focus in particular on the outcomes of NIBIN testing and the value of NIBIN-related evidence in solving gun-related investigations and reducing gun crime. The first set of analyses examined the scope and nature of interconnected gun crimes in Milwaukee. The CGIC program targets repeat shooters and networks of offenders responsible for multiple gunfire incidents through the sharing of firearms. As a first step in evaluating the impacts of the program, the research team sought to determine how much of Milwaukee’s gun violence is attributable to such offenders using data from CGIC case files and the MPD’s records management system (RMS). This portion of the study helped to define the scope of the problem targeted by the CGIC program and illuminate the program’s strategic value as a tool for improving gun crime investigations and reducing gun crime. It also illustrates the value of NIBIN testing as an analytical tool to improve the understanding of gun crime in the city. The next series of analyses examined the impact of NIBIN testing on the outcomes of gun-related investigations in Milwaukee. In principle, the CGIC program, and NIBIN testing in particular, should produce leads that help investigators solve gunfire-related crimes that might otherwise go unsolved. The research team thus examined the outcomes of NIBIN-related investigations and the role that NIBIN evidence played in these investigations using information extracted from NIBIN-related case files. In addition, the research team used data from MPD’s RMS to examine  whether the CGIC program has improved overall case closure rates for gunfire-related crimes since its major launch in 2014. Finally, the third set of analyses investigated whether NIBIN-related enforcement activity has reduced gun crime in Milwaukee. If the CGIC program is successful in targeting the most active shooters and networks in the city, then the program could produce significant incapacitation and deterrence effects that reduce the city’s overall level of shooting incidents. This was examined through a time series analysis of trends in NIBIN-related arrests and shootings (fatal and nonfatal) across Milwaukee’s police districts from 2011 through 2017. In summary, the evaluation suggests that the CGIC program in Milwaukee has high strategic value in targeting the city’s gun violence prevention efforts. Ballistics evidence generated through NIBIN testing is helping the MPD focus on repeat shooters and networks of active offenders who account for roughly half of fatal and non-fatal shootings in Milwaukee. Hence, the CGIC program has a high ceiling for its potential to reduce gun crime. NIBIN-related evidence is also helping investigators identify and apprehend more suspects in gun crime investigations. This does not mean that NIBIN evidence is a cure-all for investigating gun crime; cases with NIBIN links do not always produce arrests, nor is NIBIN evidence always critical to closing cases when it is available. Greater coordination and effort focused on NIBIN-related cases have also contributed to better outcomes for these investigations. On balance, nonetheless, systematic collection and analysis of ballistics evidence appears to be a useful strategy for solving cases and illuminating active shooters for further investigation. NIBIN-related evidence and the CGIC investigative process appear to have been particularly helpful for improving the investigation of non-fatal shootings. After an initial decline in clearances for these crimes in 2014 (due likely to a surge in gun violence throughout the city), they have been increasing during the years of the CGIC initiative. By some measures, clearances for nonfatal shootings in 2017 (the last year studied) were better than those before the program, even though gun violence levels were considerably lower during the pre-program years. Further, these recent improvements have been due specifically to improvements in clearances of cases with NIBIN-related evidence. Finally, the study provides tentative indications that NIBIN-related arrests have reduced shootings. These findings were not definitive. However, it was difficult to conduct a rigorous assessment of the program’s impacts on shootings given the lack of comparison areas for study (the program was implemented citywide, so it was not possible to compare areas with and without the program). A general rise in gun violence in Milwaukee that coincided with the implementation of the program also complicated efforts to judge the program’s impacts. In light of these findings, a longer-term study of Milwaukee’s CGIC program would seem valuable. The program’s effects may well become stronger over time as the MPD’s ballistics evidence database grows. Indeed, the rate of matches and leads from recovered ballistics evidence has grown notably during the life of the program. Hence, the research team recommends additional follow-up studies to assess the program’s longer-term impact on shooting investigations and gun crime. If impacts on gun crime can be determined more conclusively, cost-benefit analyses could also be conducted to quantify the program’s financial benefits. 

Washington, DC: National Police Foundation. 2019.. 51p.