G.K. Chesterton’s excellent Father Brown series is a collection of short stories that are superficially mystery tales, but often contain fairly deep social and religious commentary. For example, I think one of the early Father Brown tales – “The Invisible Man” – is one of the most profound short stories in English literature.
In the tale “The Vampire of the Village” the mystery hinges on the demeanor of a priest, and while I won’t give away the ending, I am going to quote from Father Brown’s explanation of how he realized the truth behind a murder: