Tess Gerritsen, trained as a medical doctor, doesn't believe in anything she can't see or touch. But she grew up in a household enlivened by her China-born mother's belief in ghosts and necromancers. "She brought home some very strange dinner guests — psychics and people who really believed in the paranormal," said the best-selling author. "So naturally I became a skeptic."

Yet Gerritsen wrote a book based on ancient texts in which are described the Nephilim, a race of evil semi-people descended from unholy unions between women and angels.

The reasons for her supernatural foray are many. As a history buff, she wanted to write a crime novel in which history provided an important club.

With an undergraduate degree in anthropology, she has always been interested in ancient man's beliefs — "this whole idea of gods or heavenly beings coming down and just kind of wreaking havoc in the lives of human beings. That theme comes back again and again," she said.

It is one way that people explain the inexplicable — madmen like Vlad the Impaler or Adolf Hitler or any number of tyrants and murderers.

It interests her that myths, legends and folk tales of the supernatural sometimes turn out to have an underpinning in scientific fact. We may not believe in a tainted strain of humanity born to do evil, but we have learned that an extra Y chromosome seems to predispose people to violence, and we may yet learn that there is further genetic predisposition to certain behaviors. Who can say?

In the end, Gerritsen is wise enough as a writer to leave the questions in her book open: Was the killer Nephilim? Or are those who believe in Nephilim just nuts? She doesn't know, and neither do we as we close her latest best-seller, "The Mephisto Club" (Ballantine Books, $25.95), which debuted at No. 3 on the New York Times best-seller list and is a main selection of the Doubleday Book Club, Literary Guild and Mystery Guilds.

As an Asian-American who writes mystery thrillers, Gerritsen is a rarity. She suspects her Chinese background does play out in her career in one way: She believes firmly in a tenet set out in a 10th-century literary movement in China that rejected flowery conventions in favor of the simplest and most straightforward storytelling. They believed that writers who used too many embellishments were being dishonest, attempting to disguise that they had no story to tell.

"I deplore writing in which style is foremost and plot and character fall by the wayside," Gerritsen said in a phone interview from a hotel room during her current book tour.

Certainly, she keeps both of these at the forefront in her novels — a scribbler from the age of 7, she's written 19 published novels, of which 10 are thrillers, many of them featuring detective Jane Rizzoli, a stubborn fighter of a woman who never gives up, and who, like Gerritsen, doesn't believe anything without proof. In "Mephisto Club," in which a group of scholars attempts to thwart the work of a vengeful killer, Jane's often wrong-headed attempts to get at the truth, and her frustration at the way the story ends, represent Gerritsen's own discomfort with the subject.

Gerritsen said Rizzoli represents something else: The way a well-built character can take over the story, guiding it where they wish it to go.

First introduced in "The Surgeon" (2001), Rizzoli was supposed to die at the end. But Gerritsen couldn't make her do it: The scenes in which the detective was killed just didn't work.

Gerritsen is a straight-ahead writer who doesn't plot or outline but just sits down with a blank sheet of paper and a pen and writes a first draft full-tilt (she does use a computer for second drafts).

"I just start writing and see what happens and that means you end up down a lot of blind alleys. In every single book I've written, I've come to a place where I can't make progress and I stop writing," she said. At this point, she takes a long drive or spends time away from her office and, thankfully, "during this non-creative period, my subconcious is telling me, you're not writing because the story has gone off the rails, and this is how." Later, she's able to resume writing.

Rizzoli in the morgue was one of those blind alleys. "And she ended up with a series," said Gerritsen of the character who has returned in four books.

The author says that her satisfaction comes from bringing forth the voices within her that want to tell their stories — "being able to entertain and to indulge my imagination."

Reach Wanda A. Adams at wadams@honoluluadvertiser.com.