This research investigates the intricate interplay between the moral emotions of shame and guilt, within justice-involved populations, with a special focus on those deemed Not Criminally Responsible (NCR) due to Mental Disorder. Recognizing the pivotal role of offense-related shame and guilt in motivating behavior and influencing psychological functioning, we conducted an extensive investigation to underscore the significance of acknowledging moral injury (MI) and its symptoms within this context. By synthesizing two comprehensive studies, our objective was twofold: to shed light on the prevalence and effects of shame and guilt, and to introduce the concept of moral injury as a fundamental lens for understanding their impact. In the first study, we examined the influence of shame and guilt on motivating behavior and psychological well-being among offending populations. We found that shame consistently relates to adverse outcomes, including defensive behaviors, self-loathing, and externalizing behaviors such as blame-shifting. Contrary to our predictions, guilt was associated with constructive responses, such as self-forgiveness, empathic concern, and assuming responsibility for one's actions. However, both shame and guilt contributed to the risk of recidivism among certain offenders. This study illuminates the intricate dynamics between moral emotions, psychopathology, and recidivism, underscoring the need to acknowledge the differential influences of the moral emotions, shame, and guilt. In the second study, we developed and validated the Moral Injury Screener in the Offending Population NCR (MIO-NCR), a self-report measure that assesses MI in justice-involved individuals, particularly NCR individuals. Through rigorous psychometric analysis, the MIO-NCR demonstrated promising criterion and construct validity. Our findings emphasized the centrality of guilt and betrayal in MI experienced by NCR individuals, aligning with contemporary syndromal definitions. The MIO-NCR, an invaluable tool, enables promising identification of MI within the NCR population. By consolidating these studies, we found that shame and guilt manifest profoundly withinthe justice-involved population, underscoring the value of MI and its core symptoms. The current thesis not only reaffirms the importance of understanding moral emotions but also advances knowledge on MI within this unique context. Our research provides a framework for developing a comprehensive approach to intervention and rehabilitation that recognizes the intricate relations between moral emotions, psychopathology, and recidivism, ultimately fostering healthier outcomes for justice-involved individuals. / Thesis / Master of Science (MSc) / This study delves into moral injury experienced by individuals labelled non-criminally responsible (NCR) due to mental health issues within the criminal justice system. Moral injury captures the emotional turmoil, including guilt and shame, arising from engaging in morally conflicting actions or facing betrayal. Our research explores the influence of moral emotions like shame and guilt on those involved in criminal activities. We discovered shame often leads to negative behaviors and self-disapproval, while guilt promotes self-forgiveness and empathy. Both emotions impact the likelihood of reoffending. We also designed and validated a new tool, the Moral Injury Screener, to grasp moral distress in NCR individuals. This tool revealed that guilt and perceived betrayal are central to their moral struggles. Recognizing these feelings is vital for understanding and addressing moral injury within the criminal justice system.