Except, without substantial cause to search flats, the police had to play it safe and potentially evidence was lost. The resulting investigation went on for years. Nobody wanted a repeat of that. We just had to hope that the evidence was there and that, in the coming days, it would rise to the surface.

5

IT WASN’T, AND it didn’t. The best and most careful scientific brains in the country couldn’t find any physical evidence that established a direct link between the five suspects and the crime. Tulloch had no choice, once the ninety-six hours had passed, but to release them.

As November grew old and the last month of the year champed at its heels, the threat of violence hung over London like the sour wind that precedes a plague. The five suspects, named on the internet if not in British newspapers, lived in a state of siege, with windows broken, walls graffitied, even a car torched. We had to give each of them police protection, which did nothing to increase our popularity in the city. Our officers were harangued on the streets. Retaliations started. A pig’s head was left on the minaret of a mosque. A veiled woman was pushed on to the line of an underground train. Luckily, she was pulled off again before she came to any harm.

As for me, well, I still hadn’t been reassigned following the big case, so I drifted on to the Chowdhury investigation and no one objected. We talked to the victim’s immediate family and his extended one. We talked to his friends and his colleagues. We found fresh suspects and brought them in: other young men in the area with a history of violence. We combed their bodies and their flats for a droplet of petrol, a discarded match-head. We compared footprints in the mud of the park to shoes we found in cupboards. We checked alibis and then we checked them again. For ten days we threw resources at the case. We got nowhere.

In the meantime, London pulled its Santa Claus outfit from the box in the loft and its citizens started asking each other how preparations for Christmas were going. The night sky above Regent Street was hung with vast crystal cobwebs, whilst statues, which could have been carved from diamonds, appeared on rooftops and peered down at us. At street level, icicles gleamed from window ledges and you had to get close and watch for drips to know whether they were real or not.

The daily castigation of the Metropolitan Police went on. The attack had been our fault, because we’d fostered a climate in which society believed black lives meant little; the failure to bring justice to the Chowdhury family was similarly our fault.

And throughout it all, I couldn’t help feeling that the blame lay primarily with me. That there’d been some detail I’d missed: a scar, a tattoo, a distinctive item of clothing. Something I’d heard, something I’d seen. Anything that would provide a direct link between what I’d witnessed that night and those who were suspected of the crime. It didn’t help that I had a feeling at the back of my mind that there really was something; but at the back was where it was staying.

There were two people I could have talked to about it. One was on remand in Holloway prison, waiting for a trial that would probably result in a twenty-year prison sentence for multiple murder. The other was in a hospital bed, trying to recover from a near-fatal bullet wound. Two very tricky sets of circumstances, both entirely my fault.

So it was just me, alone, with some very disturbing pictures in my head. And then, one Monday night, some ten days after the attack, I saw the woman in black.

6

ALL DAY, YELLOW clouds had mustered over London, getting thicker, heavier and lower with each hour that passed. Some time in the afternoon, the canopy had collapsed under the strain. It didn’t so much splinter into a million tiny fragments of white as burst open and release the waiting onslaught. For the following few hours, snow fell like fog, thick and all-encompassing, masking everything. People who ventured out did so with heads down and eyes half closed. Offices closed early. Traffic slowed, cars skidded, buses relentlessly turned the snow to brown slush.

By early evening, the onslaught had calmed, but there were several inches of snow on the ground. I was in the top flat of a house in my street, interviewing the elderly couple who lived there in the hope that they’d seen something on the night in question. I wasn’t overly hopeful, because they’d been interviewed once already and memories fade with every passing day. On the other hand, their back windows directly overlooked the park. Had they been so inclined, they could have had a ringside view.

Twenty minutes in, it wasn’t going well. They’d argued that visibility at the back of the house was very poor, especially at night, and said that neither of them had great eyesight. I’d maintained that if they’d switched off the lights they’d have had a close-to-perfect view, and pointed out that they both wore spectacles. They humoured me by switching the lights off. Ah, yes, they agreed, a very good view, and didn’t London look lovely in the snow? But, you see, they never walked round their flat in the dark, and on winter evenings they always drew the curtains.

It was hopeless. I thanked them for their time. They turned away, the man to switch the lights back on, the woman to answer the piercing call of the kettle she’d insisted on filling. I remained at the window for one last second.

And there she was. Unmistakable against the backdrop of white. A solitary figure in the park, wearing long, loose robes of black, on the exact spot where the man had died. I only saw her for a few seconds before the lights flicked on, but I could tell that she was both tall and slim, and, even standing statue-still, she gave the impression of both poise and grace. At the same time, her bowed head, her clenched hands, spoke of terrible sadness.

I don’t believe in ghosts. The world we know has more than enough to scare us, without us conjuring up imaginary fears of our own. But there was something about the sight of her that struck me hard, causing an almost physical reaction. I was conscious of a constriction in my chest, a trembling in my hands, the slightest feeling of breathlessness.

I made my excuses to the elderly couple and ran back down to the street. Whilst I had no real reason to connect the woman in the park with the crime, something about the graceful but slightly shapeless way the robes had hung around her body had made me think of the burka. And her head had been indistinct, as though a loose headscarf covered it. I was pretty certain she was a Muslim woman come to grieve alone at the spot where someone close to her had died. And that might not go well.

Just over a week after the murder, the public mood remained highly volatile. There had been several racially tainted incidents, insignificant in themselves, but worrying in their number. Flowers had been left at the park for the man who’d died. And those same flowers had been pissed on by the less sympathetic. I really didn’t fancy the chances of a Muslim woman on her own, confronted by a few of our local yobs. I stopped at the park gates. After the murder, the Parks Department had increased security to the tune of two heavy-duty chains, secured with padlocks, around the gates. They were still in place.

So how had my quarry got in? Climbing railings wasn’t too tricky – I was about to do it myself – but in an ankle-length robe? And, more to the point, how had she got out? Because she wasn’t there any more.

I stepped closer, almost touching the cellophane-wrapped flowers that lined the railings. Still no sign of her. I found a crossbar on the gates that would give me enough height and scrambled up, swung both legs over and dropped to the ground.