Almost 200 years after she died, Jane Austen's early death at the age of just 41 has been attributed to many things, from cancer to Addison's disease. Now sleuthing from a crime novelist has uncovered a new possibility: arsenic poisoning.

Author Lindsay Ashford moved to Austen's village of Chawton three years ago, and began writing her new crime novel in the library of the novelist's brother Edward's former home, Chawton House. She soon became engrossed in old volumes of Austen's letters, and one morning spotted a sentence Austen wrote just a few months before she died: "I am considerably better now and am recovering my looks a little, which have been bad enough, black and white and every wrong colour."

Having researched modern forensic techniques and poisons for her crime novels, Ashford immediately realised the symptoms could be ascribed to arsenic poisoning, which can cause "raindrop" pigmentation, where patches of skin go brown or black, and other areas go white.

Shortly afterwards she met the former president of the Jane Austen Society of North America, who told her that the lock of Austen's hair on display at a nearby museum had been tested for arsenic by the now deceased American couple who bought it an auction in 1948, coming up positive.

Ashford says that chronic arsenic poisoning gives all the symptoms Austen wrote about in her letters, unlike other possibilities which have been put forward for her death, from Addison's disease, to the cancer Hodgkin's disease and the auto-immune disease lupus. Arsenic was also widely available at the time, handed out in the form of Fowler's Solution as a treatment for everything from rheumatism – something Austen complained of in her letters – to syphilis.

"After all my research I think it's highly likely she was given a medicine containing arsenic. When you look at her list of symptoms and compare them to the list of arsenic symptoms, there is an amazing correlation," Ashford told the Guardian. "I'm quite surprised no one has thought of it before, but I don't think people realise quite how often arsenic was used as a medicine. [But] as a crime writer I've done a lot of research into arsenic, and I think it was just a bit of serendipity, that someone like me came to look at her letters with a very different eye to the eye most people cast on Jane Austen. It's just luck I have this knowledge, which most Austen academics wouldn't."

Although Ashford thinks that, based on her symptoms and on the fact arsenic was so widespread, it is "highly likely" that Austen was suffering from arsenic poisoning after being prescribed it by a doctor for another disease, she explores the possibility that the novelist was murdered with arsenic in her new novel, The Mysterious Death of Miss Austen. "I don't think murder is out of the question," she said. "Having delved into her family background, there was a lot going on that has never been revealed and there could have been a motive for murder. In the early 19th century a lot of people were getting away with murder with arsenic as a weapon, because it wasn't until the Marsh test was developed in 1836 that human remains could be analysed for the presence of arsenic."

Professor Janet Todd, editor for the Cambridge edition of Jane Austen, said that murder was implausible. "I doubt very much she would have been poisoned intentionally. I think it's very unlikely. But the possibility she had arsenic for rheumatism, say, is quite likely," she said. "It's certainly odd that she died quite so young. [But] in the absence of digging her up and finding out, which would not be appreciated, nobody knows what she died of."

Although Ashford would be keen to see Austen's bones disinterred for modern forensic analysis, she accepts this is unlikely to happen. "I can quite understand that people would be outraged by the idea," she said.