In The One I Left Behind, 13-year-old Reggie Dufrane thinks she has lost her mother, Vera, to a serial killer—until, more than two decades later, she discovers Vera is alive.

What inspired this novel?

I was looking at a milk carton one morning and—my mind goes funny places sometimes—I’m like, “Wow, wouldn’t it be really creepy if you just found a milk carton and opened it and there was a hand inside?” And then my mind continued to work, and I thought maybe it’s not just one hand, it’s a whole series of hands. I had that one image and then I asked myself all these questions, like, who’s the killer and who are the women the killer is taking, and I had to start writing to find out.

That’s a pretty frightening image.

I have a friend who calls me the queen of the nightmares because I’ve always had really bad nightmares. I keep a notebook by the side of my bed, so I’ll wake up in the night from a bad dream and my heart’s pounding and I’m really scared, but I write it down, and sometimes I get ideas for books that way. Some people say, “Write what you know.” My thing is, “Write what scares you.”

The book’s dedication to your late mother suggests there’s a lot of her in Vera, the charismatic cipher at its center.

There were definitely bits and pieces. Like Vera, my mom had a lot of secrets. All my life I had this idea that if I could unravel the mystery that was my mother, then I could help save her. But it didn’t really work. We were close, but she struggled with mental illness and alcoholism, and it was rough at times. I think we all have a kind of dark side, and that’s what keeps life—and characters—interesting. That’s one of the things that I’m drawn to write about again and again, the secrets we keep and how they shape us.

How old will your daughter be before you let her read your work?

She’s eight now, and we’re just kind of playing it by ear. Actually, this summer she decided that she was going to write her own novel. She got a notebook, and she used my little label-maker to print a title for it—The Last Time I Saw You. I was like, “Wow, that’s pretty good.” And she started writing and scribbling away. Eventually, she let me see it. She hadn’t gotten very far, but there was a murder on page one. I wasn’t sure if I should be impressed—or really worried!