Mystery over whodunnits finally solved

Julia McKenzie as Agatha Christie's Miss Marple. Photo / Supplied

Scientists find simple formula to unlock Agatha Christie’s best-selling crime novels

A panel of scientists has discovered a mathematical formula that can solve Agatha Christie's murder mysteries.

Her whodunnits have confounded millions of armchair detectives, leading them through a literary maze, before a supersleuth finally unmasks the culprit.

But scientists who have studied some of Christie's best-selling crime novels claim they can be solved with a simple formula based on the language she uses, the murder weapon, the setting and even the type of vehicle being driven.

A panel of experts analysed 26 of the author's most famous books, including Death on the Nile, Murder on the Orient Express and The Murder of Roger Ackroyd, and concluded that certain plot structures can help the reader identify the killer some time before he or she is dramatically revealed.

The panel, led by Dr Dominique Jeannerod, senior research fellow at the Institute for Collaborative Research in the Humanities at Queen's University, Belfast, found that the culprit was always introduced within the first half of the book and was likely to be emotionally involved with the victim, most being spouses or blood relations. The panel said that if there were several land vehicles in the story, the killer was likely to be female. Similarly, a prevalence of nautical vehicles suggests they were more likely to be male.

If the victim is strangled, the perpetrator is more likely to be male and if the setting is a country house, there is a 75 per cent chance they will be female.

Christie's language tends to be more negative when concerned with female killers, who are normally discovered due to a domestic item, they said. By comparison, men are normally caught using information or logic.

The panel found that if Hercule Poirot, the eccentric Belgian detective, took charge of the investigation and the cause of death was stabbing, the killer will be mentioned more frequently at the beginning of the book. If Miss Marple is the detective, and the motive for the murder is money or an affair, the killer will be mentioned more often in the later stages of the novel.

The experts also found that Christie tended to include a "main clue" revealed about halfway through the text and usually "highlighted as it appears in the text", so the reader is likely to remember it and not feel cheated by its later revelation as a clue. They said a key feature of the author's writing style was simplicity, using middle-range language and repetition.

The panel also found that the structure of a Christie novel could be reduced to a list of key events: the body will be found early on, a closed group will be presented to the reader, the detective will then be introduced and a series of red herrings will follow and finally, after it is solved, the story will be wrapped up quickly and efficiently, leaving the reader satisfied. The research was commissioned by UKTV channel Drama.

Adrian Wills, the general manager of Drama at UKTV, said: "Agatha Christie is the best-selling novelist of all time ... Given her ongoing popularity, we wanted to know her formula for success."

The research was commissioned to mark the 125th anniversary of Christie's birth.