Smart kid, Peroni thought, then yelled out into the airy, pregnant darkness, lit now by nothing more than the silvery light tumbling down the oculus.

“Listen, mister, I’m armed. I’m a cop. And you’re not going anywhere near this kid, not unless you come straight through me. And that’s not gonna happen. Understand?”

Then, just for form, “Best give yourself up now. Or climb out the window and curl up in the cold somewhere. You hear me?”

It was just a laugh. The kind of laugh you got in the movies-hard-edged, nasal, knowing. Foreign too, somehow, because Italians didn’t laugh like that, they didn’t know how to make such a shapeless, wordless sound become a figure of speech in itself, full of meaning, brimming with malevolence.

All the same, a man couldn’t scare you just by laughing. Not even this guy, with his magic scalpel and his skilful fixation on shapes.

No. Peroni knew why the sound made him shrink inside himself, shivering, wondering which way to look. It was the way the laughter echoed symmetrically around the hidden axes of the building, the way it ran along some hidden geometric path, crossing and recrossing the empty interior, time and time again, almost as if the man who made the noise planned it that way, rolled his own voice into some mystic complex of ley lines until it floated upwards and out of the ancient dead eye, out towards the moon.

Peroni flipped the safety catch on his service pistol and tried to remember the last time the weapon had been fired in anger.

“LAURA LEE? Who the hell is Laura Lee?”

Emily Deacon had an answer already. She just wanted to make him earn it.

“Let’s take this one step at a time. Decode the first message before anything else. Remember, this is three days after Kaspar has killed my dad in Beijing. Can that be a coincidence?”

Anything could be a coincidence, Costa thought. You could ruin an entire investigation by reading too much into shreds of half-related information like this.

“Maybe.”

“No! Think about it. Kaspar’s reached right into the heart of the US diplomatic service here. He’s murdered a military attaché. He knows, as sure as hell, there’ll be all kinds of people on his back. So what do these guys chasing him do?”

It could be true. He saw the logic. “You think they sent him this message?”

“Damn right I do. Maybe it’s us. Maybe the CIA. I don’t know. But someone from our side is dialing into his private line. And they’re telling him, ”We know who you are, we know where you’ve been, we know what you’ve done. Time to call it a day, Bill K, before you get hurt too.“ ”

Costa wondered about the implications of that idea. “They seem very forgiving, considering the circumstances.”

“You noticed?” she replied with a brief, icy scowl.

“And Leapman?”

She cast him a sideways glance.

“Have you talked this through with him?”

“Do you really think that would be wise right now? If he doesn’t know already, he’ll go ballistic when he discovers how I found out. And if he does…”

Leapman knew. At least that’s what she suspected. Costa thought about the way the FBI agent had acted ever since that first unexpected meeting in the Pantheon. Some unspoken knowledge seemed to underpin everything he did.

“And the ziggurat?”

She keyed up something on the computer: a page full of technical archaeological jargon and three photos of a mound-like site.

“A ziggurat’s a kind of ancient temple in Iraq. My guess is it’s what Kaspar used as a base for his mission. There’s nothing in any of the official records, of course. But a UN archaeological inspection team was sent into Iraq last summer to try to assess the damage to historical monuments caused by two wars and the Saddam regime. I found this…”

The page was about a temple close to a place called Shiltagh, near the banks of the Euphrates between Al Hillah and Karbala, slap in the middle of ancient Mesopotamia. It was less well known-or, as the report put it, less well documented-than the famous ziggurat at Ur. But it had been damaged during the first Gulf War. What must once have been a low, stepped pyramid was now a crumbling, wrecked mound, its original outline only faintly discernible. Mortar craters pockmarked the broad ceremonial staircase entrance.

“Looks like it must have been a hell of a battle,” he murmured.

“Exactly,” she agreed. “This isn’t collateral damage. It’s not aerial bombardment either. There was one big, vicious firefight here and the report dates the damage to 1991.”

“So why’s this place special?”

“For two reasons. The allied troops never got this far in 1991. There couldn’t have been a pitched battle between conventional soldiers here.”

“All the same-”

She hit a key and said, interrupting him, “Look at the pattern, Nic. The sacred cut. It’s everywhere. This is where he gets it from.”

She keyed up a photo of what he assumed was the subterranean interior of the ziggurat. The walls were peppered with bullet marks. Huge chunks had been carved out of the masonry around the door as if someone had tried to fight off an entering attacker. But the pattern was unmistakable: carved stucco on the walls, repeating itself in every direction. And elsewhere too. There were what looked like spent munitions boxes, wrecked equipment. At the centre was a pile of dark material, clumped together in a heap.

She hit the zoom key on the photo. The material became clearer: bales of ancient camouflage webbing.

“This has the pattern too,” she said. “They’d probably use it for making sleeping quarters, getting a little privacy. It’s just a coincidence, of course. The webbing’s got that shape because that’s how it’s made. Maybe it makes it strong, I don’t know. But, what with the walls and the webbing, I imagine that’s all he saw when they came for him, when he watched the rest of his team getting taken, killed, all around him. On the walls. In the quarters they’d made for themselves. Can you imagine what that must have been like?”

The floor, the low, curving ceiling, reminded Nic of what he’d seen painted in blood in the tiny apartment that stank of meat, just a few hours ago.

“I imagine it wouldn’t leave you. Ever.”

“Right,” she agreed. “So what do you do? You live that nightmare over and over again until you understand what caused it. You get free. You hunt people down in the same kind of sacred places and see if that same pattern gives you any answers.”

She looked into his eyes, not flinching. “Do you think he’s found some answers? Do you think he’s even close?”

He thought of the single word written in blood in the dead woman’s apartment. “Not close enough. When he killed that woman he wrote something, over and over, underneath the pattern. A question. ”Who?“ ”

It didn’t seem to make any sense to her either.

“He’s been killing people he knew,” she said. “Why would he ask that?”

“I don’t know. You said they’d all been strangled with a cord?”

“That’s right,” she agreed.

“No, it’s not. He didn’t use cord. At least not in the Pantheon. It was this stuff. Webbing, wrapped up into a ligature. Teresa held that information back. Leapman is going wild. It was the same with the woman we found today. Teresa got positive ID back from forensic on the first sample. This is US military issue webbing. You can’t buy it retail. And it’s not from years ago either. This particular type wasn’t manufactured until last year. As far as we can work out, the only place it’s been used in the field is Iraq.”

“Whoa.” She sighed. “Now you’re the one who’s going too fast.”

He had to ask. “If this man is that consistent, surely he would have used it on the others? Did he?”

“I don’t know.”

Costa said nothing.

She squinted at him, then pointed at the computer. “You think I’m holding out on you? After this?”