In O’Rawe’s Northern Heist (Melville House, Apr.), James “Ructions” O’Hare and other former Irish Republican Army paramilitaries plan to rob the biggest bank in Belfast.

Where did you get the idea for Northern Heist?

I always thought there was a great novel in the Northern Bank robbery in Belfast in 2004. It almost ended the Good Friday Agreement peace process, because the British and Irish governments said the IRA did it. I have no absolute proof, but the IRA was the only outfit in Ireland who had the expertise to pull off something so intricate. I thought it was a work of art.

What was the thinking behind your use of multiple points of view?

As important as it is to get into Ructions’s mindset, it’s also important to get in the other players’ minds. Ructions isn’t a saint; he’s an out-and-out villain. This is not a victimless crime. This was about real people who were caught up in this maelstrom of criminality and traumatized by it.

What was your experience switching from nonfiction to fiction?

I found the whole process liberating—creating scenarios and saying if this happens, what’s the consequence? Sometimes I wouldn’t get it right. It wouldn’t be unusual to do six rewrites. It was like when I was at Long Kesh prison for political prisoners in Northern Ireland. I was interned there twice without trial. These guys would make Celtic harps, rubbing them down with rough sandpaper and then fine sandpaper until they got a fantastic sheen. Writing to me was like that. You’re always holding it, always making it better. You want every sentence to be unique, like nothing anyone else has read before. In In the Name of the Son, the book I wrote about Gerry Conlon, who was wrongly convicted and imprisoned as an IRA man, I had a few. I was describing his personality. Everybody loved him. He made friends all over the place. So, I wrote, “Gerry Conlon made friends like hillbillies made moonshine.” The night that I wrote that, I got drunk. I love that sort of creative writing in the middle of the story.

Irish writers, by and large, are quite tongue-in-cheek. They see beauty in things that most people don’t—beauty in people’s behavior. Irish writers try to insert humor into the most serious situations. In Northern Heist, I have a character, Ambrose Peoples, coming out onto the street with a lorry load of dough, and a preacher man on the corner says, “The wages of sin is death.” Ambrose says, “I don’t know. The wages of sin are great.”

Correction: Due to an editing error, an earlier version of this article mistakenly referred to Gerry Conlon as a member of the IRA.