I lost my balance and fell across the leather armchair. When I stood up and pulled back the door, gasping at the scented air, the man had gone. Feet sounded unevenly down the stairs, the limping gait of someone with a fractured kneecap. Another door slammed, but when I went to the sitting-room window the car park and gardens were silent.

I drew the curtains and opened the windows, then sat in the armchair and waited for the intruder’s scent to disperse. I assumed that I had been so awed by my father’s flat that I had forgotten to close the front door after me when I arrived. The visitor with the truncheon had behaved more like a housebreaker or a private detective than a neighbour calling to offer his sympathies.

When I left for my appointment with Sergeant Falconer, I found the ‘truncheon’ on the floor beside the door. I picked it up, unrolling a heavy magazine, a copy of the Journal of Paediatric Surgery.

‘I’VE THOUGHT OF IT,’ I said to Sergeant Mary Falconer. ‘Cyclops . . .’

‘Is that his name?’ She spoke slowly, as if trying to calm one of her dimmer prisoners. ‘The man in your father’s flat?’

‘No.’ I pointed through the canteen window at the roof of the Metro-Centre. ‘I meant the shopping mall. It’s a monster—it makes us seem so small.’

Without looking up from her notes, she said: ‘That’s probably the idea.’

‘Really? Why, Sergeant?’

‘So we buy things to make us grow again.’

‘That’s interesting. It’s almost a slogan. You should be working for the Metro-Centre.’

‘I hope not.’

‘I take it you don’t do your shopping there?’

‘Not if I can help it.’ Sergeant Falconer glanced into her pocket mirror, permanently to hand beside her files, and threaded a loose blonde hair into its tight braid. ‘I’d keep away from the place, Mr Pearson.’

‘I will. I wish my father had taken your advice.’

‘We all do. That was a terrible tragedy. Superintendent Leighton asked me to convey his . . .’

I waited for the sergeant to complete her sentence, but her mind had drifted away. She turned to the window, her eyes avoiding the Metro-Centre. A fast-tracked graduate entry, she was clearly destined for higher things than consoling bereaved relatives, not an ideal role for a steely but oddly vulnerable woman. She seemed unsure of me, and nervous of herself, forever glancing at her fingernails and checking her make-up, as if pieces of an elaborate disguise were in danger of falling apart. Much of her appearance was an obvious fake—the immaculate beauty-salon make-up, the breakfast TV accent, but was this part of a double bluff? In the interview room I explained that I had hardly known my father, and she listened sympathetically, though keen to get off the subject of his death. In an effort to reduce the tension, she opened her mouth and smiled at me in a surprisingly full-lipped way, almost a come-on, then retreated behind her most formal manner.

She tapped her notebook with a well-chewed pencil. ‘This man you say attacked you . . . ?’

‘No. He didn’t attack me. I attacked him. In fact, I probably injured him. He may be a doctor. You could check the local hospital.’

‘What exactly happened?’

‘I was drawing the curtains, looked round, and he was there, holding a kind of club.’ I rolled up the paediatric journal and raised it across the table, as if about to strike Sergeant Falconer on the head, then let her take it from me. ‘I probably overreacted. It’s a fault of mine.’

‘Why is that?’ The sergeant stared at me for a few seconds. ‘Do you know?’

‘I can guess.’ Something about this attractive but quirky policewoman made me want to talk. ‘My mother never remarried. I always felt I had to stick up for her. If the doctor complains, say I’ve been under a lot of stress.’

‘That’s true. Sadly, it won’t end for some time. Prepare yourself, Mr Pearson.’ In a matter-of-fact tone, as if reciting a bus timetable, she said: ‘This afternoon the accused will be brought back to Brooklands from Richmond police station. He’ll be held here overnight and appear before the magistrates tomorrow.’

‘Full marks to the police. Who is he?’

‘Duncan Christie. Aged twenty-five, white, a Brooklands resident. He’s already been charged with the murder of your father and two other victims. We expect he will be sent for trial at Guildford Crown Court.’ Sergeant Falconer pointed sternly to my bruised hands. ‘It’s important that nothing prejudices the hearing, Mr Pearson. You’ll attend court tomorrow?’

‘I’m not sure. I don’t know whether I can trust myself.’

‘I understand. The trial may not be for six months. By then . . .’

‘I’ll have calmed down? Guildford Crown Court . . . I take it he’ll be found guilty?’

‘We can’t say. I interviewed three witnesses who are certain they saw Christie with the weapon.’

‘All the same, he got away. No one stopped him.’

‘There was chaos, a complete stampede. The paramedics had to fight their way into the Metro-Centre. Four thousand people fled to the exits. Hundreds were injured trying to get out. There’s a moral there, Mr Pearson.’

‘And my father paid the price.’ Without thinking, I took her hand, surprised by its hot palm. ‘Why shoot an old man?’

‘Your father wasn’t the target, Mr Pearson.’ Quietly, she withdrew her hand, and let it lie limply on the table like an exhibit. ‘The sniper fired at random into the crowd.’

‘Insane . . . This Christie fellow, some sort of mental patient. Why was he allowed onto the streets?’

‘He was on day release from Northfield Hospital. The doctors felt he was ready to see his wife and child. It was a judgement call.’

‘You sound doubtful.’

‘We’re not psychiatrists, Mr Pearson. Christie was well known in Brooklands. He was always campaigning against the Metro-Centre.’

‘Quite a target to pick.’

Sergeant Falconer closed her files. I expected a display of passion from her, a denunciation of this psychopathic misfit, but her tone was as neutral as ice. ‘His daughter was injured by a contractor’s lorry. Some steel rails rolled off during one of his demos. The company offered compensation but he refused. He kept breaking the terms of his probation and was sectioned.’

‘Good. They got something right.’

‘It was a way of keeping him out of prison. At the time he had a lot of support.’

‘Support?’ I digested this slowly, trying not to look Sergeant Falconer in the eyes. Despite the neutral tone, I felt that she was trying to tell me something, and had invited me for coffee in the canteen so that she could address the real purpose behind our meeting. I said, calmly: ‘Sergeant? Go on.’

‘Not everyone likes the Metro-Centre. I can’t give you any names, but they think it encourages people in the wrong way. Everyone wants more and more, and if they don’t get it they’re ready to be . . .’

‘Violent? Here, in leafy Surrey? The consumer paradise? It’s hard to believe. Still, you can’t miss the banners and flags, the men in St George’s shirts.’

‘Team leaders. They help us control the crowds. Or that’s what Superintendent Leighton likes to think.’ The sergeant gazed warily at the ceiling. ‘Be careful if you go out at night, Mr Pearson.’

She sat back, turning her face in profile. The mask of the policewoman had slipped, revealing the emotional flatness of a strong-willed but insecure graduate. In her left-handed way she wanted my help. I remembered that not once had she criticized Duncan Christie, despite the pain and tragedy he had wrought.

I said: ‘Right . . . You hate the Metro-Centre, Sergeant?’

‘Not really. In a last-Thursday-of-the-month kind of way. Not hate, exactly.’

‘And the Brooklands area?’

Her shoulders eased, and she put away her pocket mirror, as if she realized that self-vigilance would never be enough. ‘I’ve applied for a transfer.’