One of legendary crime novelist Agatha Christie's most enduring mysteries may have finally been solved.

Famous for creating fictional detectives Hercule Poirot and Miss Marple, Agatha Christie's murder mystery novels are overshadowed by one particularly enduring mystery about her own life.

On December 3, 1926, Christie, who was 36 at the time, left her home in Sunningdale and drove towards Surrey. Her car was found abandoned the next morning with her driver's license inside.

Her disappearance soon became headline news and a nationwide manhunt was organized involving over 1,000 police officers and 15,000 volunteers who scoured the country for her whereabouts.

She was found alive and well after 11 days at a hotel in Harrogate. She later insisted that she had suffered from a bout of amnesia and couldn't remember what had happened to her.

Now though, more than 90 years later, biographer Andrew Wilson believes that he may have finally unravelled the mystery of what Christie had been doing during those missing days.

In his new book A Talent for Murder, he outlines his belief that Christie had actually left with the intention of taking her own life. After being overcome by her Christian belief that suicide was a sin however she felt so ashamed that she decided to blame her disappearance on memory loss.

"After her mother's death she suffered a depression that was deepened by the onset of a host of other 'private troubles, into which I would rather not enter' - troubles we now know to involve her husband," Wilson wrote.

"She suffered from insomnia, she ate less, and she felt confused, lonely and desperately unhappy."