Soon enough, exhaust fumes started to fill the space and he began to cough. He jumped out of the truck. This was the way forward. This was much more efficient.

North Manhattan Homicide

March 13, 9.56 p.m.

Denise Levene sat at her desk. There was something more to the killings than she had been able to understand in the last few hours that she’d been researching. She was reading through the remaining diaries and looking through the photographs. Gerry Ratten was trying to find Lucy Steller’s online details. Although the killer had taken her PC, many people posted photographs online, kept blogs online, even stored their whole PC backup online. He just needed a breakthrough, but at the moment, there was nothing.

Harper was already out at Union Square Park with half the police in the city. Every time Denise called, he seemed more wired and angry. She called him again. ‘How is it?’ she asked.

‘We’ve got a few thousand people in the square. The face recognition has picked up half a dozen known offenders, but no Heming. It seems smaller than we imagined it would be. We’ve got hundreds of men on the ground and no traffic coming in from any direction, so we’ve done what we can. We just have to hope that he was lying or that we get lucky. What else have you got on Lucy?’

‘Nothing yet,’ said Denise. ‘But I’m going to call Lucy’s friends. They might know something.’

‘Anything more on Sturbe?’

‘I’ve been in touch with Dr Goldenberg. He’s sourced two possible ways forward. The first is a news report from fifteen years ago. A man called Edward Sturgeon was accused of being Sturbe. He lived in Boston. It may be that our killer had some Boston connection, but I can’t find anything linking Heming and Boston.’

‘What’s the other way forward?’

‘There was a book written about Sturbe. It had a very small circulation — in fact, it only went to specialist libraries, or libraries in Jewish areas. Dr Goldenberg has found a copy and guess what?’

‘I don’t want to guess.’

‘This killer is copying his approach almost to the letter. The barbed wire was something Sturbe started in Warsaw. He captured Jews in the ghetto then allowed them to escape through barbed wire or get shot. They dragged themselves through the barbed wire until they got so caught up, they died there. He drowned others. And there’s the rings. He cut victims’ fingers off to get their gold. Our killer seems to have read this book.’

‘Any way of finding a link?’

‘Heming has lived his whole life in Brooklyn. This biography of Sturbe was held in fifteen libraries in the country. The Brooklyn Library had two copies. They had a special Jewish History section.’

‘Is there any record of who took out the book?’

‘We’re going to check.’

‘Anything else?’ asked Harper.

‘I’ll keep you updated,’ she said. ‘I’m not sure how useful this information is.’

‘Well, keep going. If he’s copying this Nazi, then there might be something that leads us to him. For example, what kind of crimes hasn’t he committed yet?’

Union Square Park

March 13, 11.41 p.m.

The vigil was almost entirely peaceful. The NYPD Command Truck was parked across the entrance to the square on the south side. Harper and Eddie Kasper arrived back from their seventh tour around the square and went inside.

‘Update?’ called Harper to Lafayette.

Lafayette was sitting at one of the seats with headphones around his neck. ‘All are negatives. Nothing but complaints of infringements on human rights.’

‘How many searches have they done?’

‘Not got the numbers. Thousands, though.’

‘No calls or emails?’

‘Nothing. What’s the mood like?’

‘Peaceful,’ said Harper. ‘Everyone just wants to remember the dead. The park’s ablaze with candlelight. It’s moving. Really moving.’

There were four other men in the Command Truck monitoring their teams and liaising with the huge media operation. Harper stood at the door and stared across at their compound.

‘If the killer doesn’t show,’ he said, ‘they’re going to have a lot of footage about the vigil.’

‘Let’s hope that’s all they’ve got,’ said Lafayette. ‘We could do without another horror story.’

‘I hear you,’ said Eddie. ‘The city’s had enough tragedy.’

Harper nodded and made his way outside again. ‘Another tour, Eddie?’

‘Damn,’ said Eddie. ‘I thought you’d never ask.’

The two cops moved back out into the darkness. The police compound took up the whole of the southern end of the park. Hundreds of police vehicles stretched out. Cops everywhere, sitting around, patrolling, and catching a bite to eat.

Harper and Eddie moved back into the park. The choppers that circled overhead were useless. This was a one-man operation. The most difficult kind of perp to catch: a man who no longer cared for his own safety. It could have been any one of the thousands of men in the park.

They walked up past the media center. The reporters were wrapped up warm, sitting on the steps of AV trucks sipping coffee from paper cups. Everyone was waiting for something to happen, but no one wanted it to. A strange mood of uncertainty pervaded the press pack. They weren’t their usual eager selves. Placards declared the need for peace and remembrance. Written messages told of someone’s deep love for a person they had lost. Flowers and tributes grew throughout the evening.

The police operation was vast, but once in the park itself it was almost invisible. There were patrol cops everywhere, but many more non-uniformed officers from the NYPD, Counter-Terrorism and the FBI. There were units at every entrance with sniffer dogs and Geiger counters, doing checks and searches. They wanted to prevent any atrocities, and individual searches were the only way.

So far, they’d confiscated drugs and nothing much else. All around the park, sitting in tight groups in the semi-darkness, were several Rapid Response Units from all parties. Counter-Terrorism’s Hercules Teams sat in blacked-out sedans at each corner of the park, waiting for orders. The NYPD’s ESU SWAT teams were stationed in big black armored Bearcats, tooled up and ready.

As they walked through the crowds of people who were singing, talking, praying and crying, it looked like whatever it was, it wasn’t going to happen.

Union Square Park

March 13, 11.56 p.m.

Crowds were still filtering in, some finding it hard to move through the streets towards the vigil. The killer stopped at the roadside and watched the people lining up and walking along with candles lit for the dead.

The crowds were different now. They were not the earlier enthusiasts or the serious mourners; these were groups of people coming out of bars and restaurants. They were probably a little drunk and looking for more excitement. And as they wandered the streets, they got caught up in the sound and mood of the all-night vigil.

The killer observed them with a sense of disgust. Revelers, unconcerned about what was happening to his city, to the country. They were mourning the loss of people who didn’t deserve to be alive, people who were part of the problem. The killer took a cigarette from a pack on the seat and lit up. His anger had lessened since he’d snatched Lucy. She was his now and he felt good about that. It gave him a strong feeling of calm to know that she was his and his alone.

He sat in his truck and watched the groups move past. He needed to find the right group. He needed to choose the right profile. It amused him to think of all the effort being expended by the cops in trying to write his profile. He could write it in two words. Pissed off.