Janice Steinberg's return to Judaism began with a fictional murder.

A mystery writer who'd penned four books about public- radio reporter and sleuth Margo Simon, Steinberg decided to set her fifth novel in Israel.

Although Steinberg was disconnected from Judaism at the time, her brother lived in Tel Aviv, and Steinberg knew she'd have a place to stay while researching the book.

As she planned her 1995 trip, Steinberg recalls, "I started thinking about what the book would be about, and I wrote myself a note: `What about Safed. Isn't that the birthplace of a minor branch of Judaism?'"

That "minor branch" of Judaism was, of course, Kabbalah. While researching "Death in a City of Mystics," Steinberg — who will appear at 12:30 p.m. Saturday at M is for Mystery in San Mateo — read all of Rabbi Lawrence Kushner's books. They illuminated a side of Judaism she hadn't seen in her childhood Reform synagogue in Milwaukee.

"I grew up with the typical Reform Judaism of the '50s and '60s," she says by phone from her San Diego home.

"I had a wonderful grounding in tikkun olam. The social justice message came across beautifully. The idea that Judaism was a rich, spiritual tradition didn't come across."

While attending the University of Wisconsin and U.C. Irvine, she avoided synagogue but got involved in the anti-war movement and the effort to create alternative schools.

Social activism "seemed like a logical extension of everything I had learned in Judaism," she says.

Margo Simon, the main character in Steinberg's books, is an assimilated Jew, but her mother, Alice, has rediscovered Judaism. In "Death in a City of Mystics," Alice goes to Israel and falls in love with Safed. After mistakenly drinking a poisonous herb tea, she falls down Ma'alot Olei HaGardom, the long, hillside stairway that divides the Jewish and Arab quarters there. Her detective daughter comes to help her heal but finds herself sleuthing again.

The book has a contemporary feel, even touching on the current tensions between Orthodox and non-Orthodox Jews. Alice's Kabbalah teacher is a controversial woman named Batsheva who on Erev Lag B'Omer dies under suspicious circumstances — which is the primary mystery of the book.

Steinberg's own spiritual search took a major turn when she made the research trip to Israel. Prior to the visit, she had explored Eastern religion, women's ceremonies and Unitarian Universalism.

"Safed was so magical," says Steinberg, who's now a member of a Reconstructionist synagogue, Dor Hadash, in San Diego. "The place itself really cast a spell. So, I think that precipitated my starting to do a great deal of reading [about Judaism].

"People have different paths back. Mine was committing a fictional murder.

The increasing influence of women in Judaism also drew Steinberg back. Attending her niece's bat mitzvah in Seattle in 1994 was a revelation.

"On the bimah with her was her grandmother, her aunt, and the rabbi, Vicki Hollander. It was all women. It was so profound for me. I'd just never seen that before."

Reading Judith Plaskow's "Standing Again at Sinai" further inspired her.

"I found it really meaningful that she was questioning all the things that I was, but she was remaining within Judaism and insisting that Judaism has a lot of richness.

"In the time that I had nothing to do with Judaism, she and a number of other feminists had been raising the really important questions and making a lot of changes," Steinberg adds. "It was a different religion from the one I had left."

At 48, Steinberg is now studying for her bat mitzvah and is active in planning women's Rosh Chodesh ceremonies at her synagogue.

Like fellow Jewish mystery writers Faye Kellerman and Rochelle Krich — Steinberg has found that the religion meshes well with the genre. Justice, she says, is the unifying theme.

"Questions of good and evil. One of the things that I really enjoyed in doing the research on this book was learning about the yetzer ha tov [impulse for good] and the yetzer harah, [impulse for evil], the idea that they really are in a dynamic balance. You don't try to get rid of the yetzer harah. You'd be in trouble if you did. It's so necessary for life to continue."

Sleuthing isn't so different from Torah study says Steinberg, who appeared earlier this week at the Jewish Book Fair at the Contra Costa Jewish Community Center in Walnut Creek and at M.C. Newburn Books in Albany. "When I go to Torah study now, that's what we do with the text. That process of questioning everything is a very Jewish kind of process."

Kellerman and Krich each have characters who discover they are Jewish later in life. Though Steinberg's character of Margo Simon knew she was Jewish, the author sees a parallel.

"Her family made such an effort to blend in, to be Americans like everyone else; they lost a lot of the richness."

Steinberg will appear at 12:30 p.m. Saturday at M is for Mystery, 74 E. Third Ave., San Mateo. Information: (650) 401-8077.

"Death in a City of Mystics" by Janice Steinberg (268 pages, Berkeley Prime Crime, $5.99).