Elvira Blake

Elvira Blake is the main antagonist of Dame Agatha Christie's 1965 Miss Marple novel, At Bertram's Hotel. She was the daughter of Lord Coniston and Bess Sedgwick. She appeared as an attempted murder victim in the novel, but ended up being discovered as the murderer herself. She was portrayed by Helena Mitchell in the 1987 BBC adaptation and by Emily Beecham in the 2007 adaptation from Agatha Christie's Marple.

In other adpatations
In neither of the film/television adaptation, Elvira had gone free like that in the novel. Both of the adaptations featured Elvira being arrested by the end of the series.

BBC Adaptation
In the 1987 BBC version, most of the characteristics of Elvira remained faithful to the novels. By the end of the film, Marple exposed Elvira's true nature by revealing the latter's diary detailing the plans during her denouement, and Elvira confessed the truth. However, she begged Davy not to reveal the truth as she would lose Malinowski and it didn't matter she went with the police.

Agatha Christie's Marple
In the 2007 adaptation, Elvira's motivation is changed from that in the novel. She and Malinowski were no longer seriously interested in each other, since Malinowski backed off when he realised Elvira is Bess's daughter. Elvira reproached her mother for this, but never mentioned the matter again. Her emotional attachment in the adaption is to her friend, Brigit Milford (based on the novel's Bridget), whose role is expanded.

Several years earlier, Elvira wanted to go swimming in a river; she pressured Brigit into getting in, but backed out from getting in herself. Nevertheless, the river was contaminated, causing Brigit suffered from polio that caused her right hand paralyzed permenantly. Guilt-ridden, Elviratried to make Brigit's life more comfortable where possible. Miss Marple's denouement revealed that Elvira would need a great deal of money to support Brigit to enjoy her life, which meant she had to remove any obstacles in her inheritence.

During the murder of Gorman, Brigit caused the lights to surge by running the bath to flood, so that the hotel guests were moved to the Saloon and had a view of the street. Soon, Brigit disguised as Elvira in a copy of dress and veil before she went out in the public. Elvira hid herself in the corner and fired several missed shots at her friend with sniper rifle. When guests and Gorman came towards Brigit, Elvira shot Gorman dead. After this, Brigit fired several shots at the unseen sniper and then went to the basement. In the meantime, Elvira used the staff stairs while disguising as a maid, and they had a rendevouz.

Besides killing Gorman, Elvira also killed Tilly Rice, an original character added to the adaptation. Turned out, Tilly was blackmailing Elvira about the secret of her mother's first marriage, so Elvira killed her after she killed Gorman. However, Brigit fired with her left hand and when Elvira swapped she fired with her right hand, which caused the problem in their plot.

Trivia

 * Elvira is the second "victim" who was revealed as the true main culprit by the end of a Christie story. The first was the culprit from Peril at End House.