Blood, guts and a nice line in serial killers

She may look like an Avon lady, but Kathy Reichs spends her time cutting up dead bodies. Ann Treneman meets the pathologist turned bestselling thriller writer.

Kathy Reichs spends her life minutely examining corpses to expose foul play, and she is only too happy to explain what happens to our bodies after we no longer need them. For example, to clean away rotting flesh and allow a closer examination of a skeleton she recommends immersing it in Spic and Span - the Canadian version of Flash. Apparently you should never boil-wash, the process works best at a slightly lower temperature! Kathy Reichs relishes passing on these tricks of her trade in a very matter- of-fact way - she also has a book to promote.

There was a time when nobody wanted to hear about what she did at the office; now she is the centre of attention at parties. Her novel Deja Dead has already spent two weeks as Britain's bestselling hardback, emulating its success in America and Canada.

Deja Dead is a thriller based on 15 years working for the Laboratoire de Sciences Judiciaire et de Medecine Legale in the province of Quebec. What Patricia Cornwell writes about, she does for real. She writes about her workspace where "the antiseptic gleam of the stainless steel never really eradicates the images of human carnage. The fans and disinfectant never quite win over the smell of ripened death."

"I am normally quite clinical," explains Ms Reichs. "I have observations and measurements to make. There is a report to be written too. Although I never want to dehumanise and become totally detached." Yet with her statistical analysis of bone lengths, taking microscopic sections and counting bone cells to age adults, she makes her job seem more like solving a puzzle. "You need to know the context of a find. Was it on the surface, was it buried? Was it in the water, how acidic was the soil? Did you have scavenging animals? If I have information along those lines I can date the body. However, once all the tissues are gone it is harder to tell whether it is 10 years or 30 years old."

Her tone is always that of a scientist. "I have a case at the moment, we know who it is, when she died and how. There are six bullet holes in her head. She was dismembered and thrown in a lake. The question here is what kind of tool was used. I will be focusing on the traces left by the knife or the saw."

I was surprised to discover that Ms Reichs has not yet decided whether there is life after death. Amazingly enough, someone who has to take all her street clothes off and wear surgical scrubs so that she does not reek of her most decayed customers seems never to have given the topic even passing consideration. When I ask if she thinks the previous owners of the bodies she is piecing back together might be looking down and watching as she works, Ms Reichs looks at me if as if I have arrived from another planet.

What, then, drives her to continue with what must be some very unsavoury cases: "I get a lot of satisfaction out of contributing to giving somebody an identity. To giving a family closure - your missing daughter is here, we've identified her. I hate to ever let somebody be buried as a Jane Doe. I also like going to court and testifying so a serial murderer can be got off the streets."

Her book brings this passion to life much better than she can ever convey face to face. Although there are moments when the plot creeks as she finds ways of bringing her forensic anthropologist character out of the laboratory and into the action, her writing is good. The great strength is that Ms Reichs knows her subject-matter inside out. "I testified on a serial case which gave me a theme for the book. The killer, who is now serving three life sentences, was arrested for one murder and admitted killing another woman two years earlier. He dismembered her body and buried it in plastic sacks in five different locations."

I wonder how she feels sitting in the witness box after she has spent hours and hours sifting through their gruesome handiwork. "I usually feel totally underwhelmed. You look at this nondescript little guy who could be your uncle."

Not all of her work involves foul play, she has been analysing the bones of a woman called Jeanne le Ber who died in 1714 and has been proposed for sainthood. "When she was 18 she went into seclusion and stayed there until she died in her fifties. She did two things: praying and weaving tapestries." They knew where she was buried but needed to know which remains belonged to Jeanne le Ber and which to her family. Kathy Reichs' job has been to make the identification. "The priests and nuns supervised the exhumation and we brought her to the lab. When you kneel a lot you hyper-flex your toes; we found the right arthritic pattern and a flattened heel. She also had lovely grooves in both her upper and lower incisors from year after year of pulling the thread through her teeth. By also establishing the age and sex, I had a positive identification."

There has been a cultural shift. We are not just fascinated by gory crimes but we want to get even closer to reality and be able to smell the rotting flesh. We want to overdose on all the authentic details from professionals who have witnessed everything. Is this a sign we are becoming an even sicker society or perhaps that we are at last prepared to be honest and look death in the eye? I hope it is the latter. Dying should not be taboo - after all, none of us is going to live for ever.

`Deja Dead' is published by Heinemann at pounds 10