Hey, maybe this year would be different.

‘You have to be like Caesar’s wife in a case like this,’ said Tulloch half an hour later, when I joined her on Aamir’s doorstep and kicked the snow off my boots. ‘We all do.’

‘Whiter than white?’ I suggested. Tulloch glared and then gestured for me to go ahead.

Aamir’s flat was on the first floor of an early-twentieth-century house. At the top of the stairs, I spotted the crime-scene tape around one of the doors and stepped to one side. Tulloch unlocked the door.

The flat was four good-sized rooms – living, bed, bath and kitchen – and was contemporary and Western in style. It did not seem like the home of a scion of the Chowdhury family. The living space was decorated in shades of oatmeal and ivory. Apart from traces of grey fingerprint powder, it was immaculately tidy.

‘Quite stylish, isn’t it?’ Tulloch said.

‘Feels like the sort of place you would live in,’ I replied, as I stepped further into the room and peered into a gleaming white kitchen. The stark cooking area bore no resemblance to the crowded kitchen at the Chowdhury family home, where every work surface was crowded with implements and exotic ingredients and gleaming copper hung from every inch of ceiling.

‘I wanted you to see it,’ she went on, ‘because of your theory that Aamir might have been seeing a white woman. I admit this does feel to me like the taste of an educated Western woman.’

She was right. I thought briefly of the young women on the list I’d made at the Baileys’ house, the sisters and girlfriends of the suspects, and simply couldn’t see a woman from that background in this flat.

I began a slow prowl around the room. The bookshelf was busy, but the books seemed to be mainly medical textbooks. On the top shelf was something book-shaped wrapped in purple cloth.

‘That’ll be the Koran,’ said Tulloch, who was watching me. ‘There’s also a prayer mat in a bedroom cupboard.

‘Shoplifting incident aside, I’d barely expect someone like Aamir to come on to the radar screen of our five suspects,’ I said. ‘He was educated, a doctor, he obviously had money. It doesn’t make sense.’

‘He spent a lot of time in their neighbourhood,’ said Tulloch. ‘His own family lived close by. A lot of people in the area report seeing him or his car fairly regularly.’

‘Do you burn someone to death because they’ve caught you shoplifting?’

‘Most racist murders I can think of are provoked by much less. Isn’t that the point? It’s about skin colour, not actions.’

I reached the bedroom and paused on the threshold. How exactly, I wondered, had Aamir’s parents felt about the double bed in the room? Weren’t Muslim men supposed to be celibate until marriage? Or, if some level of experimentation were permitted, surely they wouldn’t entertain their partners at home?

‘Anything on the Shahid Karim money-laundering lead?’ I called back over my shoulder.

‘Nothing we can prove so far,’ replied Tulloch. ‘Karim seems to be quite close to Aamir’s older brother. We’re keeping an eye on it.’

On the wall facing me was a large, framed photograph of a modern ballet. Lilac smoke filled a large, empty space in which androgynous figures stretched and twisted their bodies into impossible shapes. In the forefront was a male figure wearing leggings that matched his pale-brown skin so closely he almost looked nude. Both his arms were stretched high, and balanced on his hands in a manner that looked impossible, certainly for any length of time, was a waif-like fair-haired woman with large eyes and a heart-shaped face. There was something about the way she hung in mid-air, head back, hair flowing down, that looked decidedly sensual.

‘That’s unusual,’ said Tulloch, joining me in the doorway. ‘Muslims don’t usually display images of people on their walls. Not even family photographs.’

I remembered the lack of photographs in the Chowdhury home and stepped closer.

‘Obviously a dance fan, though,’ she went on. ‘He had two tickets to see the Rambert Dance Company three days after he died. We have no idea who he was planning to go with.’

‘That’s not the Rambert,’ I said, looking at the printed text in the bottom left-hand corner of the poster, then back up again at the beautiful, slender woman at its centre. ‘London City Ballet. Recent production. Do you think we can find out who she is?’

Tulloch stepped closer and took a photograph of the poster with her phone. ‘I’m sure we can,’ she said.

She turned to leave the room, then looked back at me. ‘What?’ she said.

‘Not sure,’ I replied, still looking at the poster. ‘But there’s been something bothering me about the night Aamir was killed, something I’m missing, and for some reason, being here is making me think of it again.’

‘Something you saw or heard but that didn’t register properly?’

‘Probably. It’s no good, I just can’t think.’

‘So don’t force it.’

I followed her into the living room. ‘Any feminine toiletries in the bathroom?’ I asked.

She shook her head. ‘Just male stuff.’

‘I still think he had a girlfriend,’ I said.

‘Your mysterious woman in black,’ said Tulloch. ‘Did she show up again?’

I told her about my stake-out the previous evening. When I got to the part about the woman foraging in the bin for food, her face took on a sceptical look.

‘Lacey, she sounds like one of the homeless. She probably found the burka in a dustbin somewhere and is wearing it for warmth.’

‘So why’s she hanging around the park?’

‘Same reason anyone else would,’ said Tulloch. ‘Curiosity. To relieve the boredom. On the off-chance someone leaves something valuable behind amongst the tributes.’

I thought back. The woman I’d seen, albeit cloaked in loose black robes, had looked strong and agile. Homeless people tend not to be. I was still in the bedroom doorway and my eyes went back to the ballet poster. Dancers were notoriously strong and fit.

‘Seriously, do you know many men who voluntarily watch modern ballet?’ I asked.

‘Well, not many,’ said Tulloch. ‘But I don’t tend to move in arty circles. And how many sophisticated white women would hang around a crime scene at night in very distinctive fancy dress?’

Fair play, she had a point.

‘If you see her again, by all means bring her in for questioning,’ said Tulloch. ‘I do agree that it’s odd. But what we need is something concrete on some of our suspects, and we won’t get that by hunting ghosts.’

I agreed with her. She was my boss, why wouldn’t I? But as we said goodnight on the doorstep, I was already making plans for a night of ghost-hunting.

14

I WAITED UNTIL the park was closed before slipping in through the broken railing and making my way over the crazy cobweb of prints in the snow to the spot where the flowers lay. The tributes left immediately after Aamir’s death had all shrivelled in the cold, but a solitary red rose lay amongst them. It had been plucked from a garden, one of the rare blooms that cling on in London even into December. Its petals were scorched and limp with frost, but its colour was as vibrant as spilled blood in the moonlight.

She brought this, I thought.

I bent and left my own offering. Not for Aamir, this one, but for the woman who’d loved him and who, I increasingly believed, needed my help. It was a carrier bag of food: sandwiches, fruit juice, chocolate. I’d also left a note, written in three languages with the help of Google Translate. I won’t hurt you, it said, in English, Urdu and Arabic. Trust me. And I’d included my address. With no need to hang around, I went back to my house, climbed to the roof and waited until the woman in black appeared.

I didn’t have to wait long this time. I watched her walk across the snow, bend, open the carrier bag and find my note. She read it and stood up, startled, looking round at the houses that ran close by the park, probably knowing she was being watched.