The Evidence Is In on Patricia Cornwell : Novelist: The protagonist of her mysteries is a medical examiner inspired by the Va. doctor who is her boss.

Edgar Allan Poe, from whom all mystery fiction is thought to flow, made scientific deduction one of its ingredients. Sir Arthur Conan Doyle, inventing Sherlock Holmes’ celebrated monograph on cigar ashes, made the great detective a kind of one-man amateur crime lab (although he also occasionally used science as a bluff to induce miscreants to confess).

Lately, forensic medicine--including the profiling of psychopathic types featured in Thomas Harris’ “The Silence of the Lambs”--is enjoying a freshened and ever more specific vogue. It has indeed launched the mystery-writing career of Patricia Cornwell, who has been working in the Chief Medical Examiner’s office in Richmond, Va., and is thus able to write with uncommon knowledgeability.

Cornwell’s first novel, “Postmortem,” published in 1990, was very well-reviewed and, as first mystery novels go, a commercial success. It went so well that her publisher, Scribner’s, sent her on the road with her just-out second novel, “Body of Evidence.” The author tour has been an infrequent phenomenon for mystery writers, but crime-writing generally is on a rising wave of popularity and Cornwell’s recent cross-country visitations (“If it’s Thursday, this must be L.A.”) are a response to the renewed interest.

Her protagonist is a medical examiner named Kay Scarpetta, who was inspired by Dr. Marcella Fiero, who is indeed a medical examiner in Richmond, and with whom Cornwell has been working for five years. (Cornwell’s third novel is already with her editor, and it is not clear how long she can juggle her two careers.)

Cornwell, a brisk, petite woman who is Patsy to her friends, grew up in North Carolina, not far from Billy Graham, and her first book was a biography of Graham’s wife, Ruth. Cornwell had joined the Charlotte Observer just out of Davidson College.

“I started out as a clerk, and begged for stories to write. After six months they hired me as a reporter and very shortly after that the police beat opened up and they said, ‘Guess what?’ And I was horrified. I’d never even read murder mysteries.”

But “the innocent lamb,” as she thinks of herself in those days, went at the job obsessively. “I’d go out and do a lot of things I wouldn’t ever do now. Interview prostitutes and pimps and climb onto rooftops to interview snipers. At that age, you think you’ll live forever.”

Her then-husband moved them to Richmond so he could attend graduate school and she wrote the Ruth Graham biography there. She then bought some Agatha Christie and P.D. James novels and wrote three mysteries of her own, none of which sold and none of which should have sold, she now realizes. “Poor imitations.” Like most overnight successes, hers wasn’t. “I had a long road of failure,” she says.

She realized, not least, her baleful ignorance about criminal investigation. “If you’re a police reporter, you never get beyond the yellow tape.”

In 1984, she went to the medical examiner’s office for research and soon found herself a job there. She worked a 40-hour week and also became a volunteer police officer. “I did three years of police work, riding with homicide detectives at least once a week, if not twice, on their midnight shifts. I don’t know how I did it. I don’t think I’d have the energy anymore.”

But it was invaluable for a writer. “It exposed me to everything writers would not ordinarily see. It made me feel comfortable walking around in my characters’ shoes.”

The three unsold mysteries were painful. “It’s that terrible feeling when you’re writing something and you have to stop at every paragraph and think, ‘Well, what would he do now?’ I mean, would the medical examiner be wearing a lab coat or surgical greens, or gloves, when she comes to a scene? They’re like speed bumps you keep hitting, when you’ve got to stop to ask, ‘What would this look like.’ You can’t invent it.

“Now the best part of all this is that I don’t have that problem anymore. Now the biggest problem is, simply, making the plot work and the characters work. But I’m free of all the little technological brier patches.”

Her experience as a police reporter and then in the morgue where she spent much of her 40-hour week persuaded her of the banality of most crime. “The most heartless and frightening thing of all is simply that what causes bad things to happen to people is usually so random and mundane.”

The best crime writing in the country now, like Cornwell’s, is inevitably a reflection of the society. “It’s a microcosm,” she says, “whether it’s the way homeless people look in the downtown streets, or the problem with violence. We live in the most violent country in the world, and I don’t know what the answer to that is. We have forensic pathologists from Great Britain who come to Richmond to study gunshot wounds in our office. They stay a month and they’ll see more gunshot wounds in that month than they’ll see the rest of their lives back home.”

Dr. Fiero, Cornwell’s inspiration, is delighted by the books and continues to be the author’s consultant and good friend. The forensics community generally seems pleased by the respectful attention, and last year the National Assn. of Medical Examiners, convening in Denver, invited Cornwell to be its luncheon speaker.

Cornwell says she doesn’t read many mysteries these days. “Sometimes, after reading some of the books on the market, I just sit and feel dirty when I get to the end. When I finish a book, even if it’s dealing with a hard reality, a lot of violence, I want to feel that there’s something redeeming out of it.”