That Affair Next Door

Originally published in 1897, That Affair Next Door is Anna Katherine Green's 8th book featuring the series-detective, Ebenezer Gryce and the first to feature the society spinster, Amelia Butterworth. Many consider the nosy Miss Butterworth to be the precursor to Agatha Christie's Miss Marple or Patricia Wentworth's Miss Silver.
The story is told from Miss Butterworth's perspective as she relates the story of a murdered young woman and how she sets out to unravel the mystery.