I didn’t say much on the drive back. I knew it was very possible that Katy Devlin’s killer was sulking in the back seat of the car, and I wasn’t sure how I felt about this. In a lot of ways, of course, I would have loved him to be our guy: he had been getting right up my nose, and if it was him then we could get rid of this eerie, dicey case almost before it began. It could be over that afternoon; I could put the old file back in the basement—Mark, who in 1984 had been about five and living somewhere very far from Dublin, was not a viable suspect—collect my pat on the back from O’Kelly, take back the taxi-rank wankers from Quigley, and forget all about Knocknaree. And yet, somehow, that felt all wrong. Partly it was the crashing, embarrassing anticlimax of the idea—I had spent much of the past twenty-four hours trying to prepare myself for wherever this case might take me, and I had expected something a lot more dramatic than one interrogation and an arrest. It was more than that, though. I am not superstitious, but if the call had come in a few minutes earlier or later, after all, or if Cassie and I hadn’t just discovered Worms, or if we had wanted a smoke, this case would have gone to Costello or someone, never to us, and it seemed impossible that so powerful and heady a thing could be coincidence. I had a sense of things stirring, rearranging themselves in some imperceptible but crucial way, tiny unseen cogs beginning to shift. Deep down, I think—ironic as it may seem—a part of me couldn’t wait to see what would happen next. 6

By the time we got back to work, Cassie had managed to extract the information that bulldozers were used only in emergencies because they destroy valuable archaeological evidence and that the Time Team were a bunch of unprofessional hacks, as well as the end of a rollie Mark had made her, which meant that if necessary we could match his DNA to the butts from the clearing without getting a warrant. It was pretty clear who was going to be the good cop today. I frisked Mark (clench-jawed, shaking his head) and put him in an interview room, while Cassie left our Satan-Free Knocknaree list on O’Kelly’s desk.

We let Mark simmer for a few minutes—he slouched in his chair and drummed an increasingly irritable riff on the table with his index fingers—

before we went in. “Hi again,” said Cassie cheerfully. “Do you want tea or coffee?”

“No. I want to get back to my job.”

“Detectives Maddox and Ryan, interviewing Mark Conor Hanly,”

Cassie told the video camera, high up in a corner. Mark whipped round, startled; then he grimaced at the camera and eased back into his slump. I pulled up a chair, threw a sheaf of crime-scene shots on the table and ignored them. “You are not obliged to say anything unless you wish to do so, but anything you do say will be taken down in writing and may be used in evidence. Got it?”