Why did you become an attorney?

I was very public-service—oriented from a young age. My father had had a pretty difficult childhood and really raised me to feel that I was fortunate to have the opportunities that I did. I felt I had something to contribute and knew early on that I wanted to go to law school. My father's work with prisoners developed in me a real fascination with crime, which led me to become a prosecutor.

What surprised you the most about being a prosecutor?

How happy the defendants were, up until the time they were caught. I was doing very high-level narcotics cases. These weren't people who committed crimes because they had no other options. They made millions of dollars, at a minimum. There wasn't a lot of angst. I also became aware of the real limits that prosecutors and cops have in the real world, contrary to popular perceptions, and the whole concept of limited resources is one that I've incorporated into both my books.

What led to your decision to switch careers and become a writer?

I loved my work so much, but the all-consuming nature of the job became difficult in the long run because I was a mother—that's another theme that runs through my Melanie Vargas stories. My writing was the product of a long, tortured struggle over whether I would continue to be a federal prosecutor. When my older son was five and my younger son was a year old, I was trying a big home-invasion case charged under the racketeering statute. The defendants were pretty scary, and I was under a lot of stress, giving me terrible nightmares, and I had a dream that became the opening sequence of my first novel, Most Wanted, involving a home invasion. So, I got the idea of writing a book about that theme and became frustrated that I had no time to write. That led me to feel much more comfortable leaving this job that I loved so much and going in new directions.

Was it harder to write your second novel, The Finishing School?

It was actually a lot easier; I had established [Melanie Vargas's] universe—I knew who the characters were, who she dealt with every day. They came much more easily for me on the second go-round. I actually struggled more with the first one, both because the characters were new to me and because I had never written book-length fiction before. The whole experience of just sitting there and waiting for the words to come had been new to me. I changed the plot structure somewhat; in my first book it's pretty clear who did the actual murder. This time, I wanted the reader to be investigating the case along with Melanie, even though in real life there usually isn't much of a whodunit aspect about the work that prosecutors do.