Sleeping Murder is a 1976 novel by Agatha Christie.
The setting is some time between the accession of King George VI in 1936 and the beginning of World War II in 1939. Gwenda Halladay Reed is a young bride from New Zealand who is setting in England with her husband Giles. Gwenda, looking for a house, finds a nice one on the south coast. The house seems oddly familiar, although Gwenda can't say why.
Suddenly a terrible memory from when she was a small child comes rushing back to her after seeing a performance of The Duchess of Malfi. The line "Cover her face; mine eyes dazzle; she died young" causes Gwenda to remember witnessing a man murder a woman named Helen, while saying that very line, in the house where Gwenda lives now. Gwenda feels compelled to find out if she really did see a murder when she was a small girl. She's helped in investigating this mystery by none other than Miss Jane Marple, who is a friend of a friend.
This is the 12th and last Miss Marple novel, and in fact the last Agatha Christie novel ever published, in October 1976, nine months after her death. However it was not the last novel Christie wrote. Christie wrote the novel in 1940 and put it aside, and the book waited 36 years for publication.
- Brother–Sister Incest: The killer is Helen's brother Dr. James Kennedy. His obsessive overprotectiveness of his sister is strongly implied to contain an element of lust for her. Miss Marple describes Kennedy's feelings for his sister as "possessive and unwholesome." and seeing as it led to his murdering her...
- Chekhov's Gun: When she first moves in to the new house Gwenda loves it, but she thinks it odd that the bushes hide the view of the ocean. The bushes were planted to obscure the spot where Helen Halliday was buried.
- Childhood Home Rediscovery: Gwenda Reed finds that the house she has moved into is where she lived as a toddler, though she had had no conscious recollection of it.
- Contrived Coincidence: Gwenda buys the very house that she lived in when she was a toddler. Justified when it's suggested that she subconsciously remembered it and that was why she bought it.
- "Dear John" Letter: The main reason why the police believed that Helen had left town alive 18 years ago was the "Dear John" Letter found in the house, in which she told Kelvan she was leaving him.
- Death by Recognition: Poor Lily Kimble meets her fate this way while alone in the woods.Lily Kimble: My, you did give me a start! I wasn't expecting to meet you here.Murderer: Gave you a surprise, did I? I've got another surprise for you.
- Driven to Suicide: It seems that guilt over his belief that he killed his wife led Kelvan Halliday to kill himself, which is why Gwenda was orphaned at the age of five.
- Finally Found the Body: Miss Marple finally figures out where Helen Halliday has been for the last 18 years: resting quietly under the bushes in back of the house.
- Foreshadowing: After Dr. Kennedy is revealed to be the killer, Miss Marple berates herself for not recognizing the significance of the quote from The Duchess of Malfi—a line uttered by a vengeful brother who brings about the death of his sister.
- Gossipy Hens: "Old ladies are supposed to be inquisitive," says Miss Marple, and she uses this trait to glean information from some of the old women in the town.
- Have a Gay Old Time: While "gay" appears in its original meaning of "cheerful", the phrase "mustard-cum-biscuit shade of wall paint" will probably raise a few eyebrows.
- Leaning on the Fourth Wall: Once Gwenda's buried memory resurfaces, Giles pronounces it "a first-class murder mystery." When she says he just likes detective stories, he says "it is a detective story."
- Never One Murder: Christie used this trope a lot and she uses it here. Lily Kimble, a maid in the employ of Helen and Kelvin 18 years ago, is murdered before she can reveal what she knows.
- Shout-Out: The Reeds go to see a performance of The Duchess of Malfi, starring John Gielgud.
- The Summation: As always, Miss Marple explains everything in the last chapter. Why did the handwriting experts judge Helen's letter from France to be authentic, when she was already dead? Because Dr. Kennedy also forged the supposedly authentic example the letter was compared to.
- Switching P.O.V.: The majority of the novel follows Gwenda, but a few chapters follow Miss Marple on her investigation, and two chapters are from the POV of Lily Kemble, a servant who was a crucial witness of what happened 18 years ago.
- Title Drop: When Miss Marple tells her friend Dr. Haydock about the mystery of the woman who may have been murdered long ago, he pronounces it "sleeping murder". He advises that one should let sleeping murder lie as one would let sleeping dogs lie.
- Who Murdered the Asshole: Subverted. Despite what we are led to believe, the victim wasn't a slut or a terrible wife. The only person who has led us to believe this—the only person left who knew her really well—has been misleading us because he killed her (and he is not exactly the picture of sanity himself).
- Your Tomcat Is Pregnant: After remembering the murder Gwenda starts remembering other things from when she lived in the house, like how she had a cat named Thomas who surprised her by birthing a litter of kittens.