People with serious mental disorders (PSMDs) are overrepresented both in prison deaths and during fatal encounters with the police in the community (deaths after police contact, DAPC). To identify common factors present across cases of who died during contact with the criminal justice system in Queensland, publicly available coroners reports were analysed (N = 38). The findings of the study indicated psychosis and mood disorders were the most common diagnosis in incarcerated PSMD deaths, and suicide was the most common cause of death for incarcerated PSMDs. Within incarcerated settings, access to healthcare records, medication compliance, risk assessment and monitoring, and safe housing of at-risk prisoners may be potential areas to explore with regard to prevention. Similarly, PSMD DAPCs were more likely to be experiencing mood or psychosis disorders than other forms of mental disorder, and suicide and police shootings were the most common causes of death. In PSMD DAPC, inadequate mental health access, treatment noncompliance and comorbid substance use were included as potential areas that could direct research efforts toward prevention.