Helen moved forward quickly, determined to capitalize on his confusion. Harris spun once more, his eyes scanning the other side of the road.

‘Don’t even think about it, Ethan,’ Helen warned as she continued her approach.

The sound of sirens was growing louder now. Perhaps they were attending the traffic accident or maybe they were coming their way – whichever it was, Helen was prepared to use them to her advantage.

‘You’re a few hundred yards from Southampton Central. We’ve got every officer on the Force heading this way right now, so do the smart thing.’

Harris looked straight at her and Helen was surprised to see that he appeared to be neither panicked nor particularly disappointed by the situation he found himself in. His mind was turning on something, Helen sensed, but what kind of calculation he was making she couldn’t say.

‘I was hoping it would be you,’ he said, casting another half-glance over his shoulder to check on the progress of the uniformed officers. ‘What did you say to me at the hospital: “We’ll get whoever did this to you.” ’

Helen didn’t give Harris the satisfaction of a reply.

‘But are you sure you’re ok, Helen? You look a little off.’

She must have made a pretty sight – blood clinging to the side of her face, her suit battered and torn, but she was determined not to be mocked.

‘All the better for seeing you,’ she countered, wiping the blood from her face with her sleeve. ‘But I’ll be even happier when we’re both in an interview suite.’

‘How did you know I’d be here?’ Harris asked, ignoring Helen’s suggestion.

‘Someone spotted you in Palmerston Park and, well, it’s the obvious place to head for if you need to get away but don’t own a car.’

Harris nodded but said nothing, casting another nervous glance over his shoulder. Helen took a step closer to him, but as she did so Ethan seemed to sense her movement and shifted away. There were only thirty feet between him and the other officers now – time was running out for him, but still he made no move to surrender.

‘I hope you won’t think too badly of me, Helen. I don’t think you liked your folks either, did you?’

Helen said nothing, refusing to get drawn in.

‘Doesn’t leave you with much, does it? If your own flesh and blood despise you. Funny thing is, I used to want their love at first. When they went out – as they did every night – I used to sneak out too. I used to wander the streets looking for them, hoping they’d see me, hoping they’d want me – but it never happened. So after a while I gave up looking, but I continued to walk the streets anyway. I liked the anonymity that darkness gave me. Can you understand that, Helen?’

Helen nodded and took a small step forward. There was no question that Ethan was different – with his soft, Asiatic features, shortened arm and stooped posture – but that would have been fine, Helen thought, if he’d had people who loved him for who he was. His mother clearly hadn’t realized she was pregnant – with a baby she’d never wanted – when she’d been drinking herself under the table every night. But that didn’t excuse her horrendous treatment of her own son, a son she deemed both ill-formed and unwanted. Helen refused to have sympathy for Ethan, given what he’d done, but his pure, aching loneliness struck a chord with her and inwardly she raged at his parents for their casual cruelty and selfishness. They were the true architects of this carnage.

‘I know exactly what you mean. Darkness can be a friend.’

‘I thought you’d understand. But then again you’ve suffered – the whole world knows how you’ve suffered – so perhaps you do know how I feel.’

‘It doesn’t excuse what you’ve done, Ethan. You murdered four people.’

‘If you can call them that.’

‘They were human beings. With husbands, children, friends –’

‘They were evil – all of them. Haters who thought nothing of belittling and abusing others for their own entertainment.’

‘Luke Simms was “evil”?’

‘Well, I guess you had to be there to know what it felt like – the whole school joining in with his taunts. My only regret is that Luke Simms didn’t burn with the rest of his family.’

For a moment Helen was speechless. Under the bridge a train rattled through noisily, its metal wheels grinding unpleasantly against the rails. It was the perfect accompaniment to Helen’s rising anger and anxiety.

‘Agnieszka was no better. She beat me and abused me. Thought a poor, damaged kid like me wouldn’t fight back. Did Naomie tell you I was in the room when she set that bitch on fire?’

‘She told me that and a lot more besides,’ Helen lied.

‘I’m sure she did.’

‘She told me every little detail of your thoughts, your plans. But do you know what the most surprising thing she said was?’

‘I don’t like playing games –’

‘She told me she loved you.’

For once Ethan had no response. Was it Helen’s imagination or did he suddenly look a little less cocksure? The assisting police officers were very close to Ethan now, but he seemed to have forgotten about them, so focused was he on Helen.

‘Which means you’ve got something over me.’ She was keen to press home the advantage. ‘I’ve read your blog, Ethan. I know how you met, how you feel about her. You called her your “angel”.’

‘She is.’

‘Why?’

‘Because she has beauty. And goodness. And serenity. Because she’s the only person I ever met who didn’t dismiss me before I’d even opened my mouth.’

‘I get all that, but here’s the thing. Naomie’s just a stone’s throw away, Ethan. Sitting alone in a police cell. And right now she’s carrying the can for your crimes. I think you owe her a little more than that, don’t you?’

Ethan said nothing in response. Helen watched his face closely for signs of guilt, signs of surrender, as she carried on:

‘She’s lonely, she’s scared, she needs you. So if you value her as much as you say you do, then let’s end this now. You can make the difference, Ethan. Tell the world it was your idea, that you duped her, that you controlled her. You can still be the hero in this story – you can still save her. But you have to come with me. And we have to do this now.’

Underneath the bridge, the passing trains provided a tense, rumbling accompaniment to their confrontation. Helen stared at Ethan for what seemed like an eternity, willing him to respond, then finally he nodded. Helen felt the tension seep from her body and she took a step forward, pulling the cuffs from her belt.

‘Did Naomie tell you how we met?’ he said suddenly.

Helen nodded, taking another small step forward.

‘Did she tell you where we met?’

‘No,’ Helen answered, unnerved by the tone of his voice.

‘Here,’ he said, gesturing to the bridge. ‘And we’ve met here pretty much every night since.’

And now Helen realized that Ethan hadn’t been heading for the train station after all. He’d been heading for this bridge.

‘Ethan, you have to come with me –’

Helen was moving forward quickly, all pretence at caution now gone, but Ethan seemed unconcerned by her approach.

‘Our special place. Our ten o’clock shot.’

Helen could hear the train getting closer and knew exactly what Harris was intending to do. He darted towards the safety barrier and Helen went with him, determined to cut him off before he could jump. With one fluid movement, he swivelled up on to the wall, but just as he flipped himself over the edge, Helen managed to grab hold of his coat. The train was almost upon them, rattling over the tracks at speed, but Helen refused to let go, dragging Harris back from the brink. This was one fight she was not prepared to lose.

Then suddenly it was Helen was who falling backwards. As she hit the kerb, she realized that Harris had slipped out of his coat and was free of her grasp. She made one last, desperate attempt to stop him, but was left clutching at thin air. Seconds later, she heard the dull crunch as his body smashed into the metal tracks and immediately after that the desperate, anguished cry of the train’s horn, as the driver realized too late what was happening.