Unseen Guardian

Create a detective story where the investigator, after being killed early in the story, continues their work as a ghost to solve their own murder.

This unique prompt blurs the lines between supernatural and criminology. How does our detective come to terms with their death and navigate this unseen world? Is their interaction limited to just their case, or can they interact with the living too? The theme of desperation and justice planted against the backdrop of supernatural elements is an interesting premise to delve into.