I became a mystery writer because of a cold case. The crime was pretty low-profile, even prosaic: the bludgeoning of a housewife in her suburban garage one hot Saturday in June 1973. Her husband was arrested, but just before trial the charges were dropped. The family moved on - scattered, really, across the country - and the case went cold. Thirty years later, it became the subject of my first mystery, Quiet Time.

What's the case?

Betty Frye's murder was personal because I was about to marry her son. The morning she was killed, she called our flat. Hours later her killer - my soon-to-be-father-in-law - paid us a surprise visit in clothes too hot for the weather and with a bruise on his forehead. His claim that he was looking for a venue for our wedding dinner became his alibi. And there it sat till I wrote Quiet Time.

I'd remarried, but Betty's murder continued to haunt me. Back in 1973, she'd been unhappy about me marrying her son, and I'd feared the wedding was the catalyst. So when my new husband suggested looking into why the case was dropped, I went to the courthouse and got the old case file. The lead investigator's grand jury transcript gave me a snapshot of the evidence and a bungler of a cop to hang a mystery on. I gave Quiet Time what Betty's murder lacked. The killer was nabbed and justice prevailed.

Life isn't so simple.

Four years after Quiet Time came out, the killer's sister saw me talking about it on a late-night rerun of a public TV show. She came forward with a confession he'd made. By then I'd published three legal thrillers, but they were no help when the killer's lawyers turned their guns on Quiet Time and me. In 1973 I'd been invisible, but now everything about the day Betty was killed was under a microscope.

If the essence of mystery is not knowing, a cold case is the ultimate mystery because nothing is resolved. Did my marriage to Betty's son play a role in her murder? (Turns out, it did.) Is it better to be haunted by your worst fears than to know the truth? In real life, what happened and why have all-too-real consequences. A cold case is hell because without those answers, you can't move on.

For the decade the cold case dragged on, I completely shut down. Under continued threat of a subpoena for my drafts and notes, all I wrote was grocery lists. The case travelled the appellate courts, and witnesses died. When it was over, I obtained the official files from 1973and the cold case and tried to write what I'd wanted Quiet Time to be. But now I knew too much. The voices were no longer in my head; now they were on audiotape. The autopsy froze Betty's life at the moment of her death. Crime scene photos made the explosion in the garage real.

But the record's who and how still weren't enough. The why came from Betty's surviving sisters, forensic and cold case experts, and the old homicide cop who hadn't bungled the case after all. Then it was my job to face my role in her murder and find meaning in the brutal act. The result is Cold Case Story, the book I'd always wanted to write.

My involvement in a real crime had another consequence: it brought me back to writing mysteries. Stories that end with who, how and why but leave it to readers to find the meaning. So they, too can turn the page.

Mystery Readers Journal