In Swanson’s The Kind Worth Killing, an angry husband meets an enigmatic woman who offers to help him kill his adulterous wife.

What role did Patricia Highsmith’s Strangers on a Train play in your creation of this novel?

It didn’t play much of a role. The idea came from a conversation I overheard when I was about 12 years old. A friend told my parents how he met a woman on a plane and she got drunk and told him her entire life story, including all her secrets. The story stuck with me. It eventually evolved into an idea for a book, and as soon as that happened, I thought, well, I better make sure it’s not too similar to Strangers on a Train. No swapping murders, and less guilt.

What writers have influenced you in tackling the topic of revenge?

True Grit, the 1968 novel by Charles Portis, is one of my favorite revenge novels. The narrator is Mattie Ross, a 14-year-old girl on a mission to avenge her father’s death. I love her voice, how practical and commonsense she is, even as she’s determined to seek justice for her father. I also love the character of Parker in Donald Westlake’s The Hunter. Parker is a bad man, but he’s been double-crossed by worse men, and he’s absolutely merciless in his determination to get his revenge. Both protagonists have zero doubts about what they are doing; it’s a good trait to have if you’re in the revenge business.

Do you feel childhood and adolescent trauma justifies sociopathic behavior?

I don’t think any of the morally suspect characters in the book had a traumatic childhood, exactly. They certainly didn’t have good childhoods, but plenty of non-murderers can make that claim.

Which character did you find most challenging to portray and why?

Probably Ted Severson, the angry husband. His motives are murkier than the women’s. He actually doesn’t have a good sense of himself. He has a dark streak, but he’ll stop short of actually doing some of the dark deeds he fantasizes about. Miranda, the wife, was probably the easiest to write about because she knows herself so well. She goes after, and usually gets, what she wants.

How did you arrive at the three-part structure with alternating point-of-view chapters?

I knew from the very beginning that I wanted to write a book that would tell a story from the alternating perspectives of two different narrators, that it would be a he-said, she-said kind of book. And I knew that this man and woman would meet on an airplane, or, as it turned out, in an airport bar. I later realized that I could put another voice in the mix, and that’s how I came up with the idea for the second part. Then, in the middle of writing the second part, I decided to include one more voice, and part three happened. I was very happy with the result.