In Boris Akunin's Sister Pelagia and the White Bulldog, a Russian bishop sends a bumbling nun to investigate the poisoning of his great-aunt Marya's beloved and rare white bulldog.
Three, if you count the dog.
A father and son are beheaded and dumped in the river.
Details of provincial Russian life add to this character-driven mystery, which extends far beyond the murder of a fat, cosseted pet. A-