Nick was too tired to pretend. ‘Bret liked looking at porn. He’s not the first guy to do that and it’s not against the law.’

‘Did he ever share his stash with you?’

It was so hard to get a handle on Royce. One minute he was aloof, a prick with a badge – the next he was trying to be your big brother.

‘I had a girlfriend.’

Royce looked unimpressed. ‘Did you see what he was looking at?’

‘Tried not to.’

Royce leaned closer. ‘Why? Was it really bad?’

‘No. Just…’

‘Did Bret ever talk about it?’

He never shut up. ‘Sometimes, I guess.’

‘Did you ever hear him mention underage girls?’

That took Nick by surprise. He did his best to let his shock show while his mind raced. There were no black-and-white answers where Bret was concerned, only sludgy shades of grey. But even he had limits.

‘Bret would never have done anything illegal.’

‘You admitted yourself he was a drug abuser. If he was still alive we could have gotten him for possession with intent, with all the pot we found in your apartment.’

‘What are you-’

Royce pushed back his chair, almost knocking over the video camera. He spread his arms and leaned over the table. The flaps of his suit jacket stretched behind him like wings. ‘Bret’s death wasn’t an accident. Someone tied him to that chair and killed him because they wanted him dead. At this stage in our investigation we don’t need to look too fucking far to find a motive.’

Nick said nothing. Royce was trying to pen him in, confirm his prejudices.

‘I don’t think you’re right,’ he said at last. ‘I told you what happened. The killer must have broken into the apartment and tied Bret up. Then they got him to call me to get me home. He only killed Bret when he realised I’d seen him on the webcam.’

‘Did you do that often? Spy on Bret?’

It was like talking to a ten-year-old. They heard what you said but took a completely different meaning.

‘I never spied on Bret. He told me to Buzz him.’

‘Excuse me?’ Royce sounded perplexed, though his expression said he knew exactly what Nick was going to say.

‘Buzz is a communications interface – software. It’s sort of instant messaging, Internet video and voice calling all in the same package.’

‘Sounds great.’ Royce switched again. ‘We’d like you to unencrypt the contents of your computer.’

‘I can’t do that. My contract with the FBI-’

‘Forget it. We can get a warrant, but it’ll look better if you cooperate.’

Nick stared at him. ‘Look better to who? I came down here to answer your questions. Am I under arrest?’

‘No.’ Royce pulled back. ‘You’re just giving us a statement. Everything’s cool.’ He glanced at the video camera. Had he slipped up? Nick began to wish he’d brought a lawyer with him.

‘Look at it from my point of view,’ Royce said, more reasonable now. ‘We’ve got the gun that killed Bret and it’s got your fingerprints all over it. We’re still waiting on the samples from your hands for gunpowder traces.’

Gunpowder traces? Did they think he’d fired the gun? Could it have got on his hands when he picked it up?

‘We’ve got witnesses who place you at the scene of the crime-’

‘Of course I was at the scene of the crime.’ Nick was almost shouting. ‘It’s where I fucking live.’

‘And you’re giving me this – frankly – incredible story about some masked guy who chased you onto the roof with a gun, then changed his mind and vanished into the night. Leaving the gun behind for you.’ Royce rested his hands on the back of the chair and leaned forward. ‘I want to believe you, Nick. Really, I do. But you’re not making it easy for me.’

Nick’s mind raced, trying to think of something that would exonerate him.

‘Max.’

‘What?’

‘Max. The kid across the hall. He was talking to me when Bret got shot. He’ll tell you I had nothing to do with it.’

For the first time that morning, Royce looked uncertain. He excused himself and left the room. When he came back, he slumped into the chair.

‘We haven’t interviewed the kid yet. His mom says he’s in shock, won’t let us near him.’

That sounded right. Max’s mother was a force-five hurricane of a woman who made up for never seeing her son by being ferociously protective of him. If he tripped on his shoelaces she’d probably have sued the sneaker manufacturer.

‘Did the kid see the gunman?’

‘I don’t know. It all happened so fast.’ Nick cleared his throat. His mouth was dry as bone. ‘I’d like to go now. Can I do that?’

XIV

Upper Rhine, 1432

The traveller walked his horse to the bluff and looked out over the valley. What did he see? The river below him, of course, quickening as it squeezed around the promontory, then easing out again into a smooth ribbon between the wooded hills. Fish basked in the shallows near the bank, flitting among the weeds that writhed like smoke in the water. Dragonflies hummed over the surface, and golden sunlight warmed the sandy bottom.

Just behind the promontory, the river lapped into a shallow bay where a tributary joined it, young and lithe in comparison to the stately Rhine. Looking down, the traveller would have seen a clearing near where the lesser river flowed out, and – if the sun was not in his eyes – a crude hut made of branches and mud. In front of it, where the shore sloped down, a table with two of its legs sawn off tilted steeply towards the water. Planks had been nailed across it in a series of ridges, like steps. The whole structure glistened with wet mud. Beside it, a hollowed-out tree trunk formed a crude trough.

The traveller twitched the bridle and guided his mount back into the trees. The path was steep, but not treacherous. Dappled sunlight brushed the forest floor; the woods hummed with the buzz of bees and insects, gradually giving way to the rush of flowing water. Soon enough, he arrived at the bank of the tributary river. It looked deeper than he had thought. He slid down from the saddle, looped the bridle around a branch and strode out into the water a few paces to check the ford.

The strong current tugged at his legs as he tried to balance on the slippery stones underfoot. Downstream, a forlorn pile of boulders marked the remains of an attempt to make a breakwater. The river had broken through, and the stones meant to stem the flow now urged it on, drawing it through the gap. Still, the traveller thought, his horse should manage it.

As he turned to go back, a beam of sunlight flashed through the trees and struck his eyes. He threw up a hand to block it, but that unbalanced him; he lunged to keep his footing, but the rock that held his weight betrayed him and toppled over. With a splash, he pitched headlong into the river.

The current seized him immediately, propelling him forward towards the channel in the broken dam. He lashed out, but the river was too strong. It spun him around like a twig. He felt himself sucked under, swallowed a mouthful of water and rose gasping to the surface. Then his head dashed against a boulder and the world went dark.

Out in the bay where the two rivers joined, a dark speck broke the silver sheen on the water. An observer from the bluffs above would have taken it for nothing, a ripple or perhaps the shadow of a hovering hawk. Closer to, however, the shadow resolved itself into something like a man. He was a wild sight. His hair reached down to his shoulders, his beard almost to his chest: both were matted with so much grime you could hardly tell the colour. He stood waist deep in the water, swaying easily in the current, his feet planted in the ooze where eels and weeds twined themselves around his legs. He scooped mud from the riverbed into a cracked wooden bucket. When the bucket was mostly full, he half-carried, half-floated it back to the shore and clambered out.