For Susan Parry, a background in science - including cutting-edge forensics - was ideal training for writing a crime novel. She talks to Sarah Foster about her passion for sleuthing, in real life and in fiction.

AS a little girl, Susan Parry loved reading, devouring tales of Sherlock Holmes at the age of nine. She also loved to write, composing stories for her own amusement. Then as she progressed through school, she found herself torn. "I was very keen to continue with English but education then meant you chose to do either arts or science," says Susan, now 56. "Once I decided I liked chemistry I had to give up English, but I've always been an avid reader - particularly of crime."

Following this momentous choice, Susan's career path was set. She threw herself into science, finding she excelled at it, and gained a degree in industrial chemistry. As a new graduate, she thought her future was in this field - then things took a different turn.

"I actually got a job in a university," says Susan, who lives in Surrey. "I was researching minerals - looking at rocks on the earth that are very similar to those on the moon. By looking at these and comparing them with moon rocks, you are able to tell the difference between how the moon and earth were formed."

The work so interested her that her employer, Imperial College London, convinced her to stay on as a lecturer. This led her into more specialist research. "My interest was finding new ways of looking at trace elements of metals in the environment," says Susan. "I had a very strong interest in looking at platinum. That's because cars have catalytic converters in them, which have platinum in them. I was tracing that in the environment to see whether there were any potential health problems. In fact, there's no evidence that there's any health risk associated with platinum emission."

It was while working on this project that Susan, by now an eminent professor, met another respected scientist, Dr Kym Jarvis. The pair hit it off immediately - and decided to set up a consultancy.

"We found that we worked very well as a team, so we formed a business partnership called Viridian," says Susan. "We act as consultants in all kinds of scientific problems, particularly related to the measurement of very low levels of metals. We do work with the Environment Agency and the Food Standards Agency, looking at the safety of food."

Through links with another company, which prepares evidence for lawyers, much of the partners' business comes from court cases. "We look at the fingerprints of metals in soils and fragments of bullets. All the time we are being asked to look at different types of things - for example, the inks on bank notes," says Susan.

With forensics increasingly being used to point to innocence or guilt, Kym and Susan's findings can be crucial. "We were involved in a very high-profile case in Suffolk," says Susan. "There was very little evidence and the accused had 11 grains of soil in his Porsche that were matched to a ditch where the body of a murdered girl was found. Interestingly, our part in that was to look at soil that was taken from the field where the accused went for football practice, and we were able to show that soil from that area also matched the 11 grains in his car."

The man was vindicated, delighting the defence and proving Kim and Susan's worth. In another case, Susan tested a sample of the victim's hair to find that arsenic was present.

Perhaps inevitably, this sleuthing experience merged with her love of fiction to spark the idea for a novel. "I think I'd always wanted to write a book," says Susan. "I decided to give it a try and normally, if I decide I want to do something, I do it. I thoroughly enjoyed it, despite the fact that it meant fitting it in on evenings and weekends. Quite a bit of it was written on trains."

She describes the end result - Corpse Way - as "a sort of cosy cottage detective story". As well as focusing on crime, it uses Susan's knowledge of the scenery of Swaledale. "My husband Mark and I have been coming up to Yorkshire since before we were married over 20 years ago," she says. "We used to come up to various parts of the Dales but very quickly homed in on Swaledale. I think we've stayed in every holiday cottage and when we had exhausted them, we decided to buy our own farmhouse."

While the story's central village is fictional, it draws heavily on the local landscape, with Reeth among the places characters visit. In ancient times, Corpse Way - a track from Keld to Grinton church - was used to carry the dead for burial.

"I love Swaledale and the lead mining that's gone on there has left an interesting heritage," says Susan, adding mischievously: "It also provides the kind of calm environment where murders might take place."

Surprisingly, she says she didn't set out to showcase her forensic expertise. "While I was writing the book, I really didn't think about it at all," she says. "There is some analysis, but I didn't set out to use it - it just crept in."

With the final draft complete, her thoughts turned to publishing. As Viridian had already published science books, taking on Corpse Way seemed a natural step.

Susan explains: "As well as the consultancy work, both Kym and I had published text books on our particular areas of science. When those books went out of print, we decided that we would continue paperback versions so that our students could get hold of them. Since then, Viridian Publishing has published a number of text books. When I had written Corpse Way, we decided we would publish it. It seemed the obvious thing to do."

Now truly bitten by the writing bug, Susan is already onto her next novel, also set in the Yorkshire Dales. Having learned from the first book, she says this one will draw more heavily on forensics. "It's very obvious that in future, this will play a more significant part in my writing," she says.

While her dream of retiring to her Swaledale bolthole may be distant, Susan is content to spend her leisure time there, walking on the moors with her husband, daughters Elspeth and Alice, and dog Elvis. For the first time since her childhood, she feels she can have the best of all worlds.

"I'm spending less time at the university now and making more time for the consultancy and my writing," she says. "They feed on each other, and I would like to think that I would be able to carry on a nice balance between my science and my writing."

* Corpse Way by Susan Parry (Viridian Publishing, £6.99) is available from book shops or direct from the publisher at PO Box 746, Woking, Surrey GU24 0AZ, www.viridian-publishing.co.uk