PW: Why did you combine your two very different series characters, J.P. Beaumont and Sheriff Joanna Brady, in the same book?

JJ: I have some fans who read whatever I write, and some who read one series and not the other. This was a way to bring those fans together. We're also hoping that people who never read my work will read this one. It was fun to write, as it gave me a chance to see Arizona through the eyes of an outsider [Beaumont]. In writing a book, there's a moment when I know it's really going to work. The scene when Joanna and Beau first meet and have a blow-up—that was the moment for me in Partners in Crime.

PW: Will they reappear together?

JJ: I don't know. I don't usually know what the book will be about until I sit down to write.

PW: Your books are set in two very different locales, Seattle and Arizona. How does the setting affect your plots and characters?

JJ: Both are ones I know well. I grew up in Bisbee, Ariz., and I live in Seattle now. That allows me to report the locale—weather, etc.—while paying attention to the characters. If I were inventing the locale at the same time as the characters and plot, it would be much more difficult. That's lazy [a laugh], although I'm not sure saying "I'm lazy" will wash. As of this past March, I've been writing for 20 years. Partners in Crime is my 27th book, and my 28th is written.

PW: To what extent are Beaumont and Brady reflections of your own experience?

JJ: I spent 18 years with a man who died of chronic alcoholism at age 42. I used to wonder why he found the people in the bars more interesting than me. I went to bars and listened to people talk. J.P. Beaumont is now a reformed alcoholic, and I think I do a good job with the male point of view. I lived in Arizona for half my life, I sold insurance, I know what it's like to be a single mother. These are all parts of Joanna Brady's character. Eleanor Lathrop, Joanna's mother, bears a striking resemblance to my mother—and she really likes Eleanor! I also think there's something that's invisible to me that my readers pick up on. I'm much happier now than when I started writing the Beaumont series, and that comes through. The fact that I found happiness again made me believe that Joanna could have a second shot at happiness.

PW:Partners in Crime may be controversial because of the murder weapon, sodium azide, an easily obtained chemical in automobile air bags. How did you learn about it?

JJ: I read about it two years ago in my University of Arizona alumni magazine, an article by an atmospherics professor who took a whiff of sodium azide and passed out cold. Since he started investigating it, he's been the subject of death threats and an investigation by the Justice Department. Sodium azide is deadlier than cyanide, there's no antidote, it's virtually undetectable. They could put a marker in it as they do with nitrates, but the auto industry has no interest in doing that. Either they have to put markers in sodium azide or, when cars are junked, the airbags have to be deployed.