‘Whitestone heard from Salman Khan’s lawyer,’ Wren told me. ‘Khan’s not coming in.’

‘He’s not coming in today?’

I could hear her breathing.

‘Max, Khan’s never coming in.’

Salman Khan’s beautiful home had burned for most of the night and the wealthy street stank of smoke and death. A body had been recovered and taken away before I arrived.

Where the house had stood on the leafy St John’s Wood avenue there was now a blackened husk, sodden and steaming – a five-million-pound monument to ruin. The great pyre had collapsed in on itself at some point, taking the roof with it, and among the wreckage you could just make out what had once been the subterranean swimming pool, now heaped with collapsed brick, bent steel, burned wood.

Fire Officer Mike Truman stood between two fire engines and watched his men carefully picking their way through the ruin. DI Gane and I were with him, Gane taking notes, while beyond the police tape uniformed officers kept back a small crowd wielding camera phones. They seemed to be mostly hired help walking dogs to the park or children to school. You didn’t see the locals walking about round here.

‘There’s evidence of some kind of accelerant,’ Truman said. ‘A petroleum distillate like diesel fuel or gasoline. But we also found a small motorbike – a child’s motorbike, if you can believe that – at the foot of the staircase, so that could explain the traces of accelerant.’

Gane said, ‘That’s the fire’s point of origin?’

Truman nodded. ‘Looks like it.’

‘But how did he die?’ I said.

‘You mean was it the fire or the smoke that killed him?’

Gane was staring at me. ‘No. DC Wolfe’s asking, did someone cut his throat?’

I had never seen a burned corpse before. I had never seen how death by fire seems to coat a body in a black substance that comes from the very centre of the earth. I had never experienced the double shock of seeing what a fire takes away, and what it leaves behind.

Every inch of living flesh on Salman Khan’s body had been replaced by something that resembled a rough black overcoat yet you could clearly see his ribcage, his teeth and the fine bones of his hands, the fingers now long and tapered with all the flesh burned away, like the fingers of a concert pianist.

The fire took away everything but left the shadow of some unimaginable pain. His mouth was open, as if crying out in agony, and his elegant hands were placed over his heart and genitalia, as if protecting himself in the last instant of life.

Whitestone and I were in a viewing room at the Iain West Forensic Suite watching on CCTV as Elsa Olsen examined Khan’s charred remains.