Hans clearly had not moved much since they’d last been there. He was bleary-eyed, with his hair sticking out in every direction. He sat on a stool with his computer screen to his side.

‘An iron bullet is rare — a 9mm Parabellum made of sintered iron is extremely rare. Take a look at this.’ Hans brought up a photograph of a bullet with a cartridge. The cartridge was black.

‘Looks like there’s a tux on a bullet,’ said Harper. ‘Like a bullet going to the Oscars.’

Hans laughed. ‘That’s a very good joke, Detective. A good ballistics joke.’

‘Come on, Hans, spill.’

‘So I sent the information across to some people I know, then I put it up on the web and got a hit. They said it might be an antique bullet. Something from the Second World War.’

Harper and Denise felt the thoughts rushing through their heads. ‘Tell us more,’ said Harper.

‘The Parabellum itself was introduced for the German Service revolver, the Luger Pistole. It’s one of the most popular cartridges in the world now. But back then, it was new.’

‘So this is a German bullet?’

‘Oh, yes. Manufactured in Poland, probably.’

‘Go on.’

‘Okay, well, sorry for the history lesson, but the Parabellum originally had a lead core. A better bullet, of course. An iron bullet is too hard. The purpose of a bullet is to cause damage in the flesh. An iron bullet can zip right through the body with no expansion. It is the expansion that brings someone down. However, in about 1942, war-time lead supplies were running low so they started making the Parabellum with an iron core. Miteisenkern. They had stocks of these bullets left over after the war. Quite often, if you try to buy a bullet from that time, it will be an iron-cored bullet.’

‘Always the pragmatists, the Germans.’

‘Yes, indeed. Now, the bullet with the iron core was given a black jacket to differentiate it.’

‘So what more do we know? Why is someone using antique bullets?’

‘Come on, Harper,’ said Denise. ‘They’re not just antique bullets, they’re army supplies. These are Nazi bullets, Harper — original Nazi bullets. He’s playing the whole part, he is the whole part.’

Harper felt the hair on his neck rise.

Apartment, Crown Heights

March 10, 2.10 p.m.

Denise Levene headed off to see Aaron Goldenberg. He was a curator at the Museum of Tolerance. If anyone was going to know how to source Second World War artefacts, it would be him. He had also been working on a couple of other pieces of information. The number on the kidnapper’s note and the words Loyalty and Valiance on the black cards.

Harper found Eddie and headed out to Lukanov’s apartment. He called Swanson and Greco.

‘I’m on my way. Any movement?’

‘No one in or out. He’s probably still sleeping.’

Harper and Eddie drove over. Eddie explained what he’d done so far. He had passed the information about the typewriter to Ratten, who had gone out over eBay and two or three Internet groups asking for a 1934 Torpedo Portable Typewriter. He’d already had two hits. Someone who had one and someone who might have one soon.

‘He’ll have a list of dealers by the time we get back.’

‘Good. But I doubt we’ll be able to trace it. If this guy’s really delusional, he could’ve bought it years ago.’

They turned into the street and saw Swanson and Greco’s car. They pulled up and got out. Greco and Swanson drove up to them.

‘Good luck,’ said Swanson.

‘Which is his room?’ said Harper.

Greco pointed. ‘Third-floor corner.’

Harper stared up. ‘Windows open all night?’

‘Yep. Lights went off at 5.27 a.m.’

‘Strange,’ said Harper.

‘Why?’

‘People close their drapes to sleep.’

‘His bedroom is at the side,’ said Greco.

‘I know,’ said Harper, ‘and the drapes aren’t drawn.’

‘Maybe he sleeps heavy,’ said Swanson.

‘You see anyone come and go?’

‘Not a thing. Just other residents.’

‘How many?’

‘Several. We got pictures, if you want.’

‘You kept an eye on the back entrance?’ Harper asked.

‘Sure. There’s two cops there.’

‘They say they saw anyone come in or out?’

‘Nothing.’

‘Girlfriend?’

‘No.’

‘Anyone else?’ said Harper.

‘A cop.’

‘What cop?’

‘The guys at the back saw him. They didn’t see him go in, but a cop came out with a perp in cuffs this morning.’

‘One cop?’ said Harper.

‘Yeah, one cop. Suppose the second cop was in the car.’

‘You said he was leading a perp?’

‘Yeah.’

‘They get a good look at that perp?’

‘No. He had a hoodie on.’

‘Fuck,’ said Harper.

‘What? It was a cop.’

‘Maybe it was a cop, maybe it was Leo and one of his crew.’

‘No, they were sure it was a cop.’

‘You don’t know that. Let me ask you.’

‘What?’

‘How many cops do you see making arrests from the projects on their own?’ The two detectives shook their heads. ‘Is that never? Or do you want more time?’

‘Hardly ever,’ said Greco.

Harper sighed. ‘Come on, he’s gone. Somehow, he’s fucking gone.’

Harper and Eddie ran up to the house, Swanson and Greco behind them. They entered the building, raced up the stairs to the third floor.

Harper stared at the door. ‘Who’s done this? Who kicked this in?’

‘You did,’ said Swanson.

‘I barged the door. The Crime Scene team bolted the door. It’s been kicked open. Careful, there might be prints.’

Harper pushed open the door. He called out, ‘Police.’

Not a sound came back. They stopped still. Were hit by the smell of urine.

They opened the door fully. ‘Looks like he’s gone,’ said Eddie.

‘How fucked up do we want to be? We lost our one lead,’ shouted Harper. He moved through to the bedroom, pushed open this door in turn. ‘Shit,’ said Harper. ‘I don’t think he’s gone.’

‘What? He’s sleeping?’

Eddie joined Harper. There was Lukanov, lying naked on the bed. Gunshot wound to the head. Feathers everywhere, a pillow marked black with residue. His torso was ripped across with the number 88 in large bloody tracks. A small black and white cat was licking at the wounds. It paused and stared at them.

Harper turned and pushed past the two detectives. ‘They killed him,’ he said. ‘He didn’t come or go, you fucking imbeciles, but someone fucking did.’

‘Who? We were supposed to tail the guy, not fucking nurse him. We weren’t looking for someone going in, were we?’

‘I guess not. Another fucking dead end.’

The body was pale, the blood dried black. Covered with Nazi tattoos from neck to ankle. The red calling card ripped across it.

‘A foot soldier,’ said Harper. ‘Dispensable. Someone they knew had betrayed them.’ He turned to Eddie. ‘We’re getting close.’

‘How do you figure?’

‘Serial killers who attack random victims according to type are difficult to trace because there’s no connection between the motive and the victim. There’s only the unlucky fact that the victim was the type.’

‘I know that.’

‘But this is no random victim — this man was killed because he knew, because he was a threat.’

‘So what?’

‘We’re in his lair, Eddie, we’re right in the heart, in the control center, with links and evidence.’

‘That’s good, right?’

‘Sure, that’s good.’

‘You don’t have the face of a man who thinks it’s good.’

‘No. He’s playing a different game now. Either he’s going to pack up, go quiet, move town and hope we never catch up with him, or…’

‘Or?’

‘Or he’s going to feel our breath on his neck and start enjoying it, like it’s some game, and then things are going to escalate fast. So fast, I’m scared.’

‘Why?’

‘Because, Eddie, these people think they’re right, and if he feels he’s pushed into a corner, if he feels that there’s no way out, he’s going to start thinking about doing some permanent damage, maybe on a different scale.’