Dumb Witness

Emily Arundel is an old woman with a lot of money and a clear idea of what her relatives think of it. She tells Poirot she is afraid that one of them is trying to kill her, and he takes her seriously enough to persuade her to cut them out of the will. It is not enough. She is poisoned anyway, and the crime hides in the medicine bottle.

The suspects are her own family, which gives the investigation an unpleasant intimacy. Poirot moves through the household collecting the small resentments that pass for normal life in a family waiting on an inheritance, and everyone has an alibi that sounds rehearsed. Her heirs drift through the house, each with a reason to be somewhere else, and the doctor is never far away. And the witness who finally points him the right way is the one nobody thinks to question: the dog. The pet sees everything and tells nobody, which is either a joke or a very quiet tragedy, depending on how you look at it.

Agatha Christie and Douglas Watkinson wrote it, Edward Bennett directed. David Suchet is Poirot and Hugh Fraser is Hastings. Ann Morrish plays Emily Arundel, Patrick Ryecart Charles, Kate Buffery Theresa, Paul Herzberg Jacob, Julia St John Bella, Norma West Wilhemina, Jonathan Newth Dr Grainger and Pauline Jameson Isabel Tripp.

It is a tidy, well-made entry that knows exactly what it is doing, and the dog is the best part of it. Poirot, who usually has to explain everything to people, finally meets a witness who needs no explanation at all. The title is the whole trick, and the series plays it straight. And the episode is a reminder that the most obvious witness is often the one standing right there, and that the best liars forget that some eyes do not blink.