At shortly after 9.30 p.m. on Friday 3 December 1926, Agatha Christie got up from her armchair and climbed the stairs of her Berkshire home.
She kissed her sleeping daughter Rosalind, aged seven, goodnight and made her way back downstairs again. Then she climbed into her Morris Cowley and drove off into the night.
She would not be seen again for eleven days.
Her disappearance would spark one of the largest manhunts ever mounted. Agatha Christie was already a famous writer and more than one thousand policemen were assigned to the case, along with hundreds of civilians.
For the first time, aeroplanes were also involved in the search.
The Home Secretary, William Joynson-Hicks, urged the police to make faster progress in finding her.
Two of Britain’s most famous crime writers, Sir Arthur Conan Doyle, creator of Sherlock Holmes, and Dorothy L. Sayers, author of the Lord Peter Wimsey series, were drawn into the search. Their specialist knowledge, it was hoped, would help find the missing writer.
It didn’t take long for the police to locate her car. It was found abandoned on a steep slope at Newlands Corner near Guildford.
But there was no sign of Agatha Christie herself and nor was there any evidence that she’d been involved in an accident.
As the first day of investigations progressed into the second and third – and there was still no sign of her – speculation began to mount.
The press had a field day, inventing ever more lurid theories as to what might have happened.
It was the perfect tabloid story, with all the elements of an Agatha Christie whodunnit. Close to the scene of the car accident was a natural spring known as the Silent Pool, where two young children were reputed to have died.
Some journalists ventured to suggest that the novelist had deliberately drowned herself.
Yet her body was nowhere to be found and suicide seemed unlikely, for her professional life had never looked so optimistic. Her sixth novel, The Murder of Roger Ackroyd, was selling well and she was already a household name.
Some said the incident was nothing more than a publicity stunt, a clever ruse to promote her new book.
Others hinted at a far more sinister turn of events. There were rumours that she’d been murdered by her husband, Archie Christie, a former First World War pilot and serial philanderer. He was known to have a mistress.
Arthur Conan Doyle, a keen occultist, tried using paranormal powers to solve the mystery. He took one of Christie’s gloves to a celebrated medium in the hope that it would provide answers. It did not.
Dorothy Sayers visited the scene of the writer’s disappearance to search for possible clues. This proved no less futile.
By the second week of the search, the news had spread around the world. It even made the front page of the New York Times.
Not until 14 December, fully eleven days after she disappeared, was Agatha Christie finally located.
She was found safe and well in a hotel in Harrogate, but in circumstances so strange that they raised more questions than they solved.
Christie herself was unable to provide any clues to what had happened. She remembered nothing. It was left to the police to piece together what might have taken place.