Dumb Witness by Agatha Christie

Miss Emily Arundell senses danger before her sudden and suspicious death, leaving behind a cryptic letter for Hercule Poirot that arrives too late. As Poirot investigates, he uncovers a web of greedy relatives, hidden resentments, and subtle manipulation. The only silent witness may be her loyal dog, Bob—whose behavior hints at what truly happened. Poirot must piece together overlooked details to expose a carefully concealed crime.