I checked my watch. Under normal circumstances, a ten-year-old boy would be on his way to bed, but I somehow doubted this was what we were going to find. I pressed the buzzer for the flat.

‘It’s bust,’ the boy yelled. ‘Just pull the door.’

‘Thanks.’ I yanked the handle and entered the building, Dan behind me. The lobby was in darkness, except for a weak light which seemed to be flickering from a doorway along a short corridor. I switched on the torch on my phone, aware that we should probably call for back-up, and wait for it to arrive. But we’d wasted so much time already, I pushed the thought from my mind. ‘Flat 286a must be where the light’s coming from,’ I said to Dan over my shoulder. ‘It corresponds with where that kid pointed.’ As we made our way along the corridor, the stench of filth and skunk hit me.

The flat door was loose on its hinges and was propped open by a broken chair. The doorway opened onto a tiny hall, and beyond that, there was a room which had been stripped and had no electricity. Inside, black bin liners had been taped over the windows to keep out the draught. Concrete floors were partially covered with board, and several people were sitting on the floor. It had probably been someone’s lounge. Now it was a squat.

Dan and I entered the room.

‘We’re looking for Ali Kousa,’ I said.

‘He ain’t here.’ A tall figure on the floor growled the words. His voice was older than the boys outside, and his attention was glued to the screen of a mobile phone.

My eyes were struggling to make out who was where. ‘How about you boys help us out? No-one’s going anywhere. Back-up is waiting for the word from me.’

‘Hey, Paki. It’s you they’re after so you speak to them.’ The tall youth on the floor stood up and hauled a boy to his feet. It was Ali. He shoved him in my direction. ‘And piss off out of here. Bringing them filthy feds here.’ He slumped back down to the ground.

I grabbed hold of Ali. ‘You’re not going anywhere. Where’s your brother?’

‘Who?’

Hadn’t Sophie said that Riad’s surname was ‘Farzat’? ‘He’s not your brother, is he?’

No answer.

‘Ali, who’s that?’ I gestured to the youth on the ground, who was muttering, swearing and fidgeting, presumably off his head on something.

‘Come on, buddy.’ Dan was beside Ali now. ‘Do yourself a favour and answer the question.’ He was eyeballing the chap on the floor.

‘Ali?’ I spoke gently, aware that Dan’s Australian accent and booming male voice sounded intimidating.

‘Let me go,’ Ali shouted. ‘He kill me if I talk to you. He fucking kill me. And all of us.’

‘Who?’