Sentinel event reviews were developed in the medical, military, and aviation fields and involve systematic assessment of the processes that resulted in a critical event such as an unexpected death of a patient or an airplane crash. The sentinel event review is intended to identify system weaknesses that resulted in the negative outcome and to inform corrective actions. Sentinel event reviews have rarely been used in the criminal justice system, although recent years have witnessed experimentation in the use of review processes to examine negative outcomes such as domestic violence homicides and drug overdoses. This study examined the development and implementation of sentinel event review processes in three midwestern cities. The sentinel event reviews built upon existing reviews of shooting incidents and extended those reviews through a systematic approach that involved deeper investigation into specific critical incidents. The research involved participant observation, review of the materials related to the sentinel event reviews, and a small number of key actor interviews. The results suggest that the reviews hold promise for informing decision makers on system weaknesses and for improving criminal justice practices. Yet, they also revealed obstacles to effective implementation and utilization of sentinel event reviews in criminal justice settings.