In the novel Mrs McGinty's Dead, Mrs Sheelagh Rendell is the second wife of Dr Rendell, with whom she lives in a house in Broadhinny named Crossways. She is a thin fair-haired pale woman with very pale blue eyes, which was also described as a tongue-tied, apprehensive woman--indeed, when Hercule Poirot first visited her, she appeared to be "startled out speaking". She tells Poirot "she heard of him being in Broadhinny, but she did not know--" and then she stopped waiting for her husband's signal to keep talking.
Poirot later interviewed Mrs Wetherby, who told him Mrs Rendell had just telephoned saying that a private investigator was in the village. Some time after that, her appoximate age is given--roughly thirty years old. Superintendent Spence said that she was one of the women in Broadhinny which had the right age to be Lily Gamboll or, alternatively, Eva Kane's daughter: Mrs Rendell, Eve Carpenter and Deirdre Henderson. Poirot remarks that Mrs Rendell is afraid of something but would not say what. Spence believed that could be significant, and thought that Poirot was suggesting she was Lily Gamboll.
When someone attempted to kill Poirot by pushing him under a train, Dr Rendell was having a surgery operation, and Mrs Rendell was at Crossways "listening to her wireless"--however this was not confirmed. At a party, Ariadne Oliver indeed did accuse Dr Rendell of having murdered Mrs McGinty and of almost killing Poirot--but this was not confirmed or denied until the end of the novel. Sheelagh Rendell described Deirdre Henderson as being pathetic. She also believed heredity was a direct consequence of the environment people live in, and Laura Upward said environment was only a secondary circumstance, a "veneer" and no more.
Later that night everyone who attended to the party tried to give their alibis for Mrs McGinty's murder, if they remembered. That night, Mrs Rendell had come to Mrs Upward's house to keep her company, while her son Robin was off. However she could not make Laura Upward hear, who had a headache and went early to sleep. The day after Mrs McGinty was killed, she said to herself that she could have encountered the killer in the dark without realizing, because at first everyone believed the culprit was a tramp who broke in.
When Poirot was lodging at Long Meadows as a paying guest, Mrs Rendell had visited him and accused him of using Mrs McGinty's death as a pretext to investigate the lives of the people in Broadhinny. She later changed topic and started to talk about anonymous letters. She asked Poirot if they were always lies, and he replied that some times they are, but he wouldn't say they were all untrue. Mrs Rendell broke down and described them as cowardly, treacherous, mean things, which Poirot agreed.
Poirot asked himself if Sheelagh could be Lily Gamboll, a girl who had murdered her aunt when she was twelve. Lily Gamboll was last heard in Ireland. Dr Rendell could have married his wife there, ignoring her past--but this was just theories and not real facts. There was one thing that seemed to confirm that theory, that Lily Gamboll was trained as a stenographer and it was easy for a stenographer to cross paths with a doctor.
Some days later, Laura Upward was strangled with a silk scarf. At the time Mrs Rendell was probably sitting at home. It later turns out that Mrs Upward rang up three women before her death: all three had the right age to be Lily Gamboll. Those were Eve Carpenter, Deirdre Henderson and Mrs Rendell. Deirdre was not considered for the part of the child killer because she had a background. Sheelagh was telephoned at around six o' clock, and her housekeeper Mrs Scott took the message.
Eve Carpenter behaved like the culprit. She paid her domestic servants to say she was at home, and they denied. Mrs Rendell seemed nervous, but she usually was a nervous type, so no one could judge by that. Sheelagh Rendell was willing to go to Mrs Upward's, but she fell asleep.
Hercule Poirot visited her again, and had the same impression he had of her at first: wary, oh her guard, and frightened of him. She told him about the telephone call, but she did not tell the police about it since she thought it didn't matter--she did not go there.
The end of the novel gives a plausible explanation regarding Mrs Rendell's fear and strange behaviour. Dr Rendell's first wife died in Leeds some years before, and the police of that city received several anonymous letters saying that he had poisoned her. There was no evidence of this, except for a detail: before her death, they both mutually insured their lives in favour of each other. Mrs Rendell probably received those letters as well, which explained the fact that she believed that Poirot's inquest of Mrs McGinty's death was just an inquest. That explained the last question: it was Doctor Rendell who tried to push Poirot under a train that night.
Poirot and Spence did not take action, but told to themselves that Sheelagh should be cautious on insuring her life in favour of her husband.
Portrayals[]
Mrs Rendell was portrayed by Amanda Root in the TV adaptation which formed part of the series Agatha Christie's Poirot. Here Dr Rendell preformed euthanasia and there was no mention of a first wife. It is Mrs Rendell and not Dr Rendell here who may have attempted to push Poirot under a train.
In Mademoiselle Mac Ginty est morte, the France Télévisions adaptation of the novel, the parallel character is Deborah Santini, wife of a psychoanalyst Leopold Santini.