I'm re-reading Agatha Christie since she is one of my favourite authors and her writing is always fun. Colonel Protheroe is a hated figure in the village, so there is no shortage of suspects when he is found dead at the vicarage. Even the vicar thinks the village is better off without Protheroe. Miss Marple is never called to assist the police, but that does not stop her from trying because she likes sleuthing. And as the vicar's wife points out, "That kind of old cat is always right.". And she is right and will solve the crime, obviously.