That seems like such a perverse impulse to me.

The alternative is to not engage with it, which would make it more frightening. I worked on a script about the Green River Killer. And I spent a lot of time in that world. No matter what aspects of it you look at, it’s about really horrible, life-denying things: destruction and grief and sadness and loss. And there is nothing romantic about it. I suppose that’s the danger with a lot of this sort of stuff is that it can make evil seem somehow attractive.

In “Prodigal Son,” is there some romance around the idea of the killer’s being so much smarter than everyone else?

Well, I liked the challenge of playing someone who seems very likable, sort of charming. He uses that disguise like animals do: bright colors to lure prey. If you’re a hunter, what you want is to be able to disguise yourself as something that will bring your prey to you. And so I came at it from that point of view — maybe this is me just rationalizing with myself, but this is genuinely what I found interesting about it — rather than looking at the character as someone who falls into that trope of the genius serial killer. So it’s less about him being smart, and more about him being dazzling.

Do you have a sense of why people are drawn to the show?

On the one hand, you’ve got a procedural aspect to it every week. And then on the other hand, you’ve got something that’s a bit more like shows you might see on streaming platforms that are threaded through. You can’t just come in and watch a single episode and get it. It’s got the police, a serial killer and also a domestic drama: What if Hannibal Lecter were Clarice’s dad?

Why does Martin kill?

Well, that’s what the show is about. He represents himself and what he’s done in a totally unreliable way. It’s always squalid reasons. It’s always furtive, secretive, shameful reasons based on trauma.

What’s it like to live with all of that in your head?

When I was doing the Green River Killer stuff, I remember getting to the last page of the first draft and I sort of fell apart for a little while after. And that was just from working on the script. In a lot of our representations of that kind of world, it seems sort of exciting and exhilarating and frightening and titillating. But the real world of it is just depressing.