Q. Your books resonate beyond their particular plots and the characters; your fiction comments on the distressed conditions that currently exist in Ireland. How does Broken Harbor express concerns about your adopted country?

I think if you write mystery, you’re going to end up, at some level, focusing on your society’s priorities and tensions and deepest fears. You’re writing about murder, the biggest fear of all—and the way that fear expresses itself is obviously going to be shaped by its time and place. Take the flood of serial–killer books in the 80s and 90s: I figure those were a response to the growing sense of isolation and anonymity in cities, where the threat isn’t your nearest and dearest any more, the way it is in small–town Agatha Christie; it’s some faceless, nameless stranger. So, while Broken Harbor was never intended to be an “issue book” or anything like that, I was writing it in Ireland from 2009 through 2011, and that seeped in.

Ireland is an epic mess. That’s the mildest way I can put it. And it’s my generation, the thirty–somethings, who are taking the brunt of it. Not me and my husband personally, or most of our friends—we were broke actors for most of the boom, so we couldn’t afford to buy a dog kennel in the middle of nowhere, never mind an actual home. That upset me at the time, but it turned out to have a silver lining in the end. Now a solid proportion of our generation are stuck on half–built, half–occupied, abandoned estates with open sewage pits and no street lighting, miles from any friends or family, and many of their houses are falling to pieces. They’re unemployed or being taxed to the point where they can’t pay their mortgages, and no one’s ever going to buy their houses so they can move on. And their belief in a sane world, a world where they have any control over their own lives, has been smashed.

That haunts me. It should never have happened; it didn’t need to happen. And because Ireland is my home and I love it, I get seriously passionate and seriously angry about terrible things that are done to, and by, this country. That ended up shaping the book.

Q. Some of the worst villains in Broken Harbor are invisible and unassailable—not just the animal in the Spains’ attic, but also the financiers and real estate promoters. What do you think about their culpability in the events of Broken Harbor?

Don’t forget the politicians. For reasons made up of a hellish brew of stupidity, cronyism, and corruption, they were right in there with the property developers and the banks, frantically urging my generation to spend ten times our income on unbuilt houses in the middle of nowhere. Our then-Prime Minister said, charmingly, that anyone who didn’t believe the property boom could last forever should kill themselves.

I don’t believe that the people who fell for the hype are innocent victims. They were grown adults, they signed the contracts, no one forced them; there are plenty of people who said no, and they had the choice to do the same. But at the same time. These are people who were trying their absolute best to do everything right. Everything and everyone around them told them that this was the right thing to do, so they did it. And I think it would be ludicrous to say that the people who urged them on are guiltless.

Psychological mystery is a natural place to explore that whole area - the ambiguity of guilt. There are other mysteries where culpability is a straightforward thing: X killed Y because X is a bad person, the end. And they’re wonderfully satisfying and necessary books, because it’s very cathartic to place and contain evil within one person, with the implication that once that person’s in jail, evil has been purged and the world of the book is safe again. But psychological mystery is a lot less at home with the idea of evil being neatly bounded and simple to confine. In psychological mystery, evil is often a facet of a lot of the characters, not just the killer, and the most evil actions don’t necessarily come from the most evil people - and so, while the justice system punishes the evil action, sometimes the truly evil people do in fact walk away, unassailable.

Q. That animal in the attic is one of the strangest touches in your story. It’s a little like the beast in Lord of the Flies. How did you hit upon it as a plot device?

That’s actually where the whole book began! One night a few years ago, I went into the kitchen, and before I could switch the light on, I half–saw something leap out from behind the toaster, zip across the counter and vanish. I jumped about three feet, but I couldn’t find any sign of anything, and my now–husband gave me a dubious look and gently mentioned my overactive imagination. I was a bit miffed, and a bit wary around the kitchen, but it wasn’t a big deal. And a couple of nights later my husband was the one who went into the kitchen, and he turned on the light in time to see a mouse doing a runner down behind the cooker.

We got some traps and a new toaster, I managed not to say “Told you so,” and that was the end of that—except that something stayed in my mind: the frightening sense of dislocation that comes when your inner reality and your outer reality get out of synch; when what you know to be true and what others see aren’t the same thing. I started thinking about what it would be like if the half–seen something had zipped past someone whose home and marriage were already under threat from outside forces; what it would be like if the mouse didn’t show up on Day 3, if this guy went on hearing his home being invaded by an animal that no one else could hear . . . And a couple of years later, that fit together in my mind with what was happening to people around the economic boom and crash—the utter dislocation between the obvious reality and what we were being told, between what people believed and what was happening all around them. Basically, Broken Harbor was written because we had mice.

Q. Your ongoing fascination with flawed heroes with tortured pasts reminds us very strongly of Greek tragedy. Does your experience with staged drama influence your writing of fiction?

I’ve never taken a creative writing course or anything like that; my equivalent, my writing training, was my time as an actor. Just about everything I learned about acting, except maybe “Never take a bite of cake just before your line,” translates to writing.

Here’s one of the things I learned: a character who’s everything he wants to be, and has everything he wants to have, isn’t interesting. Dramatically, that’s the equivalent of watching some guy sit on his sofa eating Doritos and playing Xbox for a couple of hours: yeah, he’s happy, so what? This is going nowhere. What’s interesting is a character who’s struggling towards something high–stakes, and getting held back by obstacles both outside and inside himself.

In a murder mystery, the external stakes are automatically right up there; stakes don’t get much higher than life, death, truth and justice. The internal stakes are the reason why all my narrators have been damaged, whether temporarily or permanently. Most people are, in one way or another; they’re finding ways to deal with that damage, whether by fighting it or assimilating it or suppressing it. And my books are about the cases that force the narrators to come face to face with the damage—’the cases that mean they can’t keep it under wraps and try to work around it any more, they have to confront it and either move past it or be defined by it forever.

Rob Ryan in In the Woods doesn’t manage to move beyond the damage done by his childhood friends’ disappearance; in The Likeness, Cassie Maddox is traumatized by the events of In the Woods, but through the events of the book she starts to heal; in Faithful Place, Frank Mackey’s whole perception of himself and his life is changed as he finds out the truth about his first love’s disappearance, and he ends up freed, to some extent, from his old scars. And Broken Harbor is about the case that breaks down Scorcher’s belief in an orderly world governed by reason and the law of cause and effect—the belief that’s been holding him together since childhood. Without that prop, he has to find a new and different way to live.

Or, to put it more concisely: when in doubt, mess with your character’s head.

Q. There’s a lot of thoughtful material in Broken Harbor dealing with male friendship, both between Scorcher and Richie and between Pat and Conor. As a woman, did you find it challenging make these relationships come to life on the page?

Friendship has always been hugely important to me. Probably this is obvious from the books—In the Woods and The Likeness both have friendship at their hearts. I think of it as an essential of life, like water; you can be a perfectly happy, fulfilled person without a partner, or without kids, but I’m not sure it can be done without friends. And when friendship or the capacity for friendship is under attack—because of someone’s own internal damage, like in Scorcher’s case, or because of outside pressures, like in Pat and Conor’s—it strikes right at the core of you, just as powerfully and painfully as when romantic love is under attack. If Scorcher and Richie were able to find their way, that last step to a real friendship, this book would end very differently for both of them.

At its heart, friendship is the same crucial thing whether it’s between men or women. The differences lie in the ways it’s expressed—and when you come down to it, those differences depend on who the individual people are, far more than on whether they’re men or women. I stick to focusing on the specific characters, trying to capture the ways their friendships take shape, the small trivial details that show the underlying layers of trust and love much more clearly than any amount of hugs and deep conversation. Whether the characters are men or women is a factor, sure—and luckily I’ve always had plenty of guy friends, so I’ve seen lots of male friendships in action—but it’s not the only factor, or even the most important one.

Q. Some of the childhoods you portray in Broken Harbor are deeply troubling times. What are your thoughts about childhood in general?

I was lucky: I had a happy childhood. But one thing that’s true of every childhood, happy or unhappy, is that it’s incredibly intense. You don’t have room for the levels of ambivalence and complexity that adults can manage; you’re whole–hearted. And you take in everything. I think you spend your first twenty years learning absolutely everything you’re exposed to, and the next ten or twenty years trying to unlearn the bad bits. Whatever’s in a child’s life, the child assumes it’s a universal truth.

Scorcher learned things that children shouldn’t: that the responsibility for the world rests on his shoulders; and that even the tiniest loss of control can lead to chaos. Those have been built into him, and they take their toll.

Q. Your novel is extremely frank in its confrontation of madness and the ways in which mental illness can fracture lives. Why do you think the theme of madness is so especially interesting in a police procedural novel?

That theme wasn’t deliberate. This will sound bizarre, but I didn’t even realize until a few weeks ago, when someone pointed it out to me, that almost every character in the book is mentally unstable, to some degree; that madness permeates the whole book. It’s very weird to realize just how much of a book is written by your subconscious.

I do think the theme of madness is a natural match for a police procedural—not just in criminal terms, but in psychological ones—which is probably why it shows up relatively often. Procedurals are all about order and control. Murder is the ultimate attack on that order, both societally and psychologically, and it’s up to the detectives to fight off the chaos and turn it back into some kind of order so that we have a society we can live in. Madness is the opposite journey—order fragmenting into chaos, the laws of cause and effect breaking down. The clash between those two, and what it does to a detective caught in the middle, is natural territory for a book.

Q. Your characters in Broken Harbor deal with madness—and suspicions of madness—in radically different ways, with different results. Are there lessons to be learned here?

Definitely no lessons to be learned. I don’t do those. I’m in no position to be giving anyone lessons about anything—specially mental illness, since I’ve been lucky enough, touch wood, that it hasn’t played much of a role in my life. When I write a book that touches on something as big as madness (or murder, for that matter), I’m not trying to teach anyone about it—I don’t think that’s my job, and I wouldn’t be qualified if it were. I’m just trying to understand it, even the smallest bit.

I think the theme of madness was basically inevitable when I started writing a book set in a ghost estate. Those ghost estates were created out of Irish national madness; they’re insanity made solid. There was an overwhelming cultural push towards the idea that, as long as you believe something hard enough, it automatically becomes true: if you keep believing that the boom will last forever, then of course it will, and if you doubt that, well then, it’ll be your fault if it all goes wrong! The actual facts were irrelevant and unpatriotic. There was a national–level fracture between reality and perception; perception wasn’t expected to have any link to reality.

Obviously all experience is subjective, to some extent. But when you start believing that your personal perception is all that matters, that outside reality doesn’t need to be taken into account, then you’re taking a huge leap down the path towards madness. Every form of madness, as far as I can tell, is based on that disconnect in some way or other.

One thing I’ve noticed, since someone pointed out to me what this book’s about: the characters who survive with the least psychological damage are probably Richie, Scorcher’s partner; Conor, the man who’s been spying on the Spains from an abandoned house; and Fiona, Jennifer Spain’s sister. I’m not saying they come out unscathed—they definitely don’t—but, at their cores, they retain some kind of wholeness; under all the devastation, they’re still themselves. And those three are the ones who pay most attention to what’s outside themselves. They really listen to other people; they really watch what’s going on around them; they have, or gain, an awareness that other people’s lives are as real as their own, that reality exists outside of them as well as inside. Again, this wasn’t intentional, and it’s not a lesson or anything, but it does fit with the way I see madness: that dangerous dismissal of outside reality.

Q. More than once, the tragic center of your detective plot has fallen upon a question of inadmissible evidence. Do you have anything to say to someone who might read your books and say, “There, you see? Another perfectly provable case ruined by these stupid constitutional safeguards! We’d have more justice without them”?

The fact is that the system is human, and humans are flawed. Because of that, we absolutely need safeguards, to protect innocent people and to protect justice; but inevitably, those very safeguards sometimes go wrong and end up jeopardizing the exact things they’re meant to protect—releasing a killer to kill again, for example. This is one of the many things about detectives that leaves me awestruck: their job is to navigate that Mobius strip, and to try and come as close as possible to justice within it.

Every now and then, the truth and the rules turn into the two halves of a vice grip, squashing the detective and the case between them—and some part of the detective is inevitably going to get crushed. Either he has to stand by and bite his tongue while justice gets thrown out the window, or he has to break the rules that are there for excellent and crucial reasons—and either way, a part of his integrity is sacrificed.

That’s what happens to Scorcher. His whole view of the world gets crushed in that vice–grip by the events of the book. By the end, he’s had to sacrifice his idea of who he is, and of what his life is going to be, in order to hold onto something that will make the world a recognizable, and bearable, place.

I don’t know how detectives do it.

Q. We were a bit surprised that Frank doesn’t come back for a cameo in Broken Harbor. His relationship with Scorcher in your previous book was so heavily charged.

This is one of the things I enjoy about writing linked books with a different narrator each time: you get to explore that subjectivity that I was talking about earlier, how two people can see the same person or event in two completely different lights. Frank sees his relationship with Scorcher as heavily charged—but that’s mainly because, when Scorcher resurfaces in his life, Frank’s just found out that his first love was murdered, and that the narrative that was the basis for his whole adult life isn’t true. He needs an enemy; he needs someone to fight against. Until he finds out who the killer is, Scorcher—partly because he’s so attached to the rules, which really aren’t Frank’s thing—will do nicely.

But Scorcher doesn’t really see Frank the same way. To Scorcher, Frank isn’t particularly important, at least not at this point in his life—because he doesn’t need Frank, either as an enemy or as an ally. He’s already got more than he can cope with on both fronts. Whoever killed the Spains, plus the bits of Scorcher’s past that the murder churns up, adds up to plenty of enemy for anyone, especially someone as focused and single–minded as Scorcher. As far as allies go, he’s got Richie—who may not seem like much of an ally, considering how young and how new he is, but Scorcher’s not used to having allies at all; he’s used to flying solo, and he doesn’t have an easy time wrapping his head around the idea that he’s starting to see Richie as a partner. So there wasn’t really any room for Frank in his world, or in the book.

Q. What are you working on now?

I’m partway through my fifth book, which is currently called The Secret Place. The narrator this time is Stephen Moran, Frank’s young sidekick from Faithful Place. Frank’s daughter, Holly, now sixteen, shows up at Stephen’s work with a postcard she found on the noticeboard where girls in her school can post their secrets anonymously —a postcard with a photo of a murdered teenage boy, and the caption “I KNOW WHO KILLED HIM.”

And this time Frank does come back!