Jacob Tanios

In the novel Dumb Witness, Dr Jacob Tanios is Bella's husband. He is a physician, of Greek descent, practicing in Smyrna.

Dr Tanios and Bella have two children, Edward and Mary Tanios. They live in Smyrna, but are visiting England during the events of the novel.

Dr Tanios is described as a "big-bearded jolly-looking man". He is rotund, and has brown hair and eyes. He has a beard, which is a "modest brown affair", which Hastings thinks makes him look like an artist.

Dr Tanios is very charming, and is said to be very able in his profession. He speaks English perfectly, and his voice has a pleasant timbre.

Miss Arundell disapproved of Bella's marriage to Dr Tanios, as in her mind "a Greek was almost as bad as an Argentine or a Turk".

When Dr Tanios and his wife first arrive at LIttle Green House at the beginning of the novel, he talks to Miss Arundell about the advantage of an English education, and how he regrets that he cannot afford to give such an education to his children. He then asks Bella to ask Miss Arundell for money. Bella tells him that she does not want to, but he points out that it is not for her, but for the children, and that their investments had been unlucky. Dr Tanios tells Bella that he thinks she will do what he asks, and that she usually does.

After Miss Arundell falls down the stairs, Dr Tanios carries her up to her bedroom and attends to her. He and Bella come to Little Green House again the following weekend, to check on her. Dt Tanios also visited on the weekend before Miss Arundell's final illness.

After Miss Arundell's death, Dr Tanios tells Poirot that he is of the opinion that her will was made when she was not responsible for what she was doing. He expresses the opinion that Miss Lawson did not like him, and that she had tried to prevent him from returning to Little Green House on the weekend after Miss Arundell fell down the stairs.

Dr Tanios later calls on Poirot, saying that he is worried about his wife, and that she is suffering from persecution mania. He tells Poirot that any stories his wife might tell of being in danger from him are untrue. Dr Tanios asks Poirot to let him know at once if Bella comes to him, as he wants to take her to an institution to receive treatment. He is unable to find Bella, as she has left him, and taken the children with her.

Bella later dies from an overdose of a sleeping draught. It is revealed that she did not fear her husband, but she disliked him. As time went on, she could not conceal her dislike towards him, which was why he sensed that her manner towards him had changed.