About fifty yards ahead, he caught a fleeting glimpse of the man taking the southern line. Tom darted left and found himself on a packed platform.

By the time he’d got halfway along the platform, a train had pulled in and opened its doors. He scanned the crowd quickly, letting them get on the train, moving up the platform in the space behind them. As the doors were about to shut, he caught sight of the man in black getting on about four carriages up. There was a flash of red inside the carriage and Tom jumped aboard just as the heavy metal doors skidded shut.

The train pulled away into the darkness of the tunnel ahead.

With no way through the packed carriage, Tom knew he’d never reach them in the short time he had and he’d lose them at the next station. He looked at the emergency stop handle for an instant, then pulled it.

The train started to screech to a halt, the lights flickering on and off. The crowds began to look around, worry and annoyance more than fear crossing their faces. Slowly, Tom began to move through each cabin. The lights kept flickering as his eyes scanned ahead.

As soon as the train jolted to a stop, Tom’s quarry panicked. He could see Kitty up ahead, but he knew the cops must’ve stopped the train. He scanned down through the carriages. He couldn’t see anything, but he had to go. He had to escape. He couldn’t bear the crowds, the claustrophobia, the police on his tail. He felt sweat pouring down his face as he pushed through the throng to get to the driver’s cab.

Ahead of him, Kitty was rushing through the carriages as fast as she could, terrified now and shouting as she pulled herself through the crowds. She could hear the commotion her attacker was making behind her as she reached the end of the train. She saw the man coming through the last carriage, sweat pouring down his face. The driver’s door was shut and locked. Kitty smashed her flat hand hard against it and started screaming, but the door didn’t open. She rattled the handle and pleaded, but she knew the driver wouldn’t open it. It was against all regulations. He had to sit tight and wait.

As her pursuer approached, Kitty gave up. She turned towards him with her back hard against the driver’s door, slid down the door and pulled herself into a tight little ball. She closed her eyes and bent her head as far as possible into her knees.

The man in black had nowhere to go. He turned and looked back down the train. He could see someone moving towards him, close now. He looked down at Kitty. He had no option. He smashed a window with his heel and clambered out. He hooked himself on to the side wall of the tunnel and moved to the front of the train, dropped down, and sprinted into the darkness.

Tom arrived and knelt by Kitty. ‘You’re okay now,’ he said softly. ‘We’ve got him trapped. He’s out in the tunnel. I’m going after him. You’re safe now.’ Kitty didn’t even open her eyes and Tom climbed out of the broken window. He was less than a minute behind his quarry: near enough to hear his footsteps as he sprinted ahead in the pitch dark. Tom started to run, fearing the live electric rail and trying to find a rhythm on the track.

At the next station, the cops had cleared the crowds from the platform and were waiting, staring into the dark tunnel. They heard footsteps in the tunnel and a man appeared in the opening of the station, running from something or someone. Then Harper appeared behind him.

The man tried to get up on the platform but cops spanned its length, their guns pointing down at him. Panicking, not knowing which way to turn, he turned and rushed straight at Harper.

Harper sidestepped him, caught him by the neck and threw him to the ground. A knife clattered across the rails and the man scrambled away from Harper, his heels digging into the dirt.

‘Who are you?’ said Tom.

The man looked up. ‘I don’t know who I am!’ he shouted. Harper saw the manic look in his eyes and watched as his right arm reached out towards the live rail. If he touched the line, over six hundred volts would course through his body, killing him instantly. Harper grabbed hold of his ankle and tried to pull him back, but it was too dangerous: if the man touched the rail while Harper was holding him they would both die. He looked up. Three officers were staring down their sights at them. Harper didn’t want this killer dead, either punched full of holes or fried on a train line. With one last effort, he threw himself on top of him, caught his right arm and rolled him towards the platform. The two bodies rolled twice and then the killer went limp. There was no fight left in him. Harper turned him in the dirt and stared at his face. The fucking guy was weeping. Harper wanted to break his jaw. He jammed his forearm under his chin and pulled his head up. He had the American Devil in his control on the ground. It felt good. Real good.

‘Who the fuck are you?’ he shouted. ‘Who the fuck are you, you sick bastard?’

The man was crying even harder now. ‘I’m nobody. Nobody at all. I was just following her. I wasn’t going to touch her or hurt her.’

‘I want your name,’ Harper screamed. ‘Your name!’

The man looked up. ‘Carlisle,’ he said. ‘Winston Carlisle.’

Chapter Forty-Seven

East Harlem

November 23, 6.22 p.m.

A few hours after the man in black had been rolled away from certain death, a cavalcade of red and blues screeched across the car park of the desolate halfway house up in East Harlem. The guy wouldn’t tell them where he lived, but they’d run his name through the system and in less than an hour his file came up on a screen at the NYPD database. Winston Carlisle had a record and he’d just been released into an adult housing block. The address was called through directly to Harper. He gave the order and Blue Team set off.

Winston Carlisle had been a patient at Kirby Psychiatric and Manhattan Psychiatric Center. He lived in a halfway house in East Harlem. Things were fitting together. The killings started about a month after he was moved to a non-secured room in MPC. He was free to come and go, and that’s when the killing began: a few weeks after his release from a secure ward.

The quiet parking lot up in the Heights was ripped up by the arrival of Blue Team and the rest of the task force. The halfway house was a low-roofed municipal building. The green barred door was wedged open and a nervous-looking woman sat in reception, eyes wide at the chaos of lights and activity. She’d only been in the job a week - the previous receptionist had died in a traffic accident - and was not yet used to dealing with cops.

Harper led the team through the door. The killer probably went under any number of aliases as he stalked and dated these women. He probably wore disguises. He was probably a lot smarter than he made out.

‘We’re looking for Winston Carlisle’s room,’ said Harper. The receptionist’s arm pointed towards the stairs. ‘Room fifty-two, gentlemen.’

The team made their way up to the second floor and down the corridor to the small room where Winston Carlisle lived. Eddie Kasper was at Tom Harper’s side. They’d spent the last few weeks hunting this man, terrified by his capabilities, and now they were looking at a urine-soaked bed in a six-by-nine room at the end of nowhere street. Winston Carlisle had been right. He was a nobody. A nobody who wanted to be somebody.

The two men looked at the small single bedroom and couldn’t believe that it had all started in that tiny, pathetic space.

‘So this is the home of the American Devil,’ said Kasper.