Swinson introduces a damaged, damned protagonist, Frank Marr, in The Second Girl (LB/Mulholland, June).

From the time I was 17, I always thought I’d be a writer, but after college, I got caught up with a whole mess of life experiences, from owning a record store in Seal Beach, Calif., to booking and promoting punk rock and alternative music in Long Beach, Calif. My last stop was joining the Metropolitan Police Department in Washington, D.C., where I grew up. Eight months in the academy and then a badge and a gun. A lot of my friends thought I was crazy, but it wasn’t such a drastic leap. I went from booking bands to booking bad guys... and a few bad gals.

I made detective quickly. Maybe it was a romantic notion—the writer in me had this naive idea that it would be great adventure, solving big cases, something I’d do for a few years, then write about it after. But the job got into my blood. It became something more than just a career. Over time, it changed me and how I looked at everything. It allowed me to see humanity at its best and its absolute worst. Something I never would have otherwise realized. Ever.

I was turned into a man of rules and procedure. I became the guy you didn’t want to watch certain crime shows or movies with. “That’s not how it’s done! There is no way a cop would go into that dark building chasing an armed suspect without backup! Keep your finger off the trigger, you fool!”

Eventually, my first novel, A Detailed Man, came into my head. It took a few years to write, longer to get published, but it found a home with an indie press. Several years later, after I retired, I got an idea for a character. Not a book. Not a story. Just a compelling character: Frank Marr. I spent about a year taking notes before I could start writing. And when I did, Frank freed me as a writer, because even though he’s a former police detective turned PI, he is not a man of rules and procedure, but he’s still a cop at heart, so he has a code. That’s why I had so much fun writing The Second Girl. Marr allowed me to get outside of myself. So much of what I had written before had too much of me in it. Frank Marr is not me, even though, sometimes, I would like to be him. He did come from my experiences, though, and all those years on the department, catching great cases, some tough cases, but mostly interviewing witnesses, and interrogating and debriefing prisoners. Their world was opened up to me.

I am grateful Frank Marr entered my life, but more grateful for all the years I served on the police department, because Frank would not exist otherwise.