This started out as a post in the random silliness thread, but it keeps getting longer and longer, so I thought to bring the conversation here
People other than Police who Solve Murders:[ul][]Private Detectives[]Defense Attorneys[]Reporters[]Pathologists[]Insurance Investigators[]Mystery Writers[]Gentleman Amateurs[]Nosy Little Old Ladies[]Precocious Kids[]The Post-Murder Cleaning Crew[]Psychics[]Criminology ProfessorsGhost of the victim(s)[/ul]
And nuns. Scroll down this page for a list, including Sister Mary Teresa, who featured in 10 novels (with nun-punny names) by the same author as the Father Dowling mysteries.
(I think there are a few plots, especially Sci-Fi, where the murderer kills someone and then gets amnesia, figures it out, and then is wracked with guilt. But I can’t recall any examples)