One of the first independent criminal profilers, John Philpin is an internationally recognized expert on violent behavior and criminal investigation. Philpin is a frequent consultant to law enforcement and the media. He has been a guest commentator on Court TV, 20/20 Downtown, Unsolved Mysteries, America's Most Wanted, Inside Edition, Chronicle, The Geoff Metcalf Show, The Jim Bohannon Show, Northwest Afternoon, and CBC's As It Happens. A retired psychologist, he has authored and co-written seven books and numerous articles, and the featured character in an eighth, drawing on his experience.

Patricia Sierra is an award and competition-winning writer whose poetry and stories have appeared in a variety of literary magazines. Her first publication was at age 17, when a national magazine purchased her short story. She is the author of an array of books for both young adult and adult readers, including One-Way Romance, A Boy I Never Knew, Echoes in the Grove, The Prettiest Feathers, and Tunnel of Night. Other titles include ghost-written books and independently published works. In addition to writing, Sierra had a brief moonlighting career as a private investigator. Before becoming a full-time writer, she was a radio personality and hostess of a daily television show. She and her family live in Ohio.