Grief after suicide or patient-perpetrated homicide can be complex for those involved in the patient’s care. Mental health practitioners with patients who die unexpectedly may be called to assist in the formal investigation processes that follow. The aim of this study was to examine the experience of mental health practitioners called to attend a coroner’s inquest or other forms of formal inquiry. A protocol for a systematic review was prospectively registered on PROSPERO (CRD42023400310). A thematic synthesis of existing literature was conducted. We identified six articles for inclusion and constructed three themes from our analysis: Blame and enduring hostility, In the dark, and Limited learning. We found mental health practitioners may construct narratives of self-blame. These can be reinforced by the investigatory processes that follow. Feedback from inquiries is often delivered haphazardly and may not reflect the realities of clinical work. The support given to assist practitioners through inquiry processes varied—both in amount and how helpful it was. The research conducted on this topic is limited. More qualitative research should be conducted to understand the factors that make this experience more or less difficult as well as well as what support is needed for whom.