‘Ian Peck,’ Wren said. ‘Multiple convictions. The first one ten years ago for possession of class C drugs – anabolic steroids – and class B – cannabis. Peck was buying in Amsterdam and mailing the stuff to his home address with the name of the previous occupant on the package.’

‘That old trick,’ somebody said.

Wren dropped into her seat.

‘Twelve months suspended,’ she said, scrolling down. She shook her head. ‘Four – no, five convictions for domestic violence against his girlfriend. She has a restraining order. Peck’s a freelance software consultant. After the split with his girlfriend he moved back home with Mum and Dad.’

Wren turned to look at the chief super.

‘And that’s Bob the Butcher,’ she said.

Swire’s mouth twisted with triumph. ‘Well done, everybody. Start making your preparations. We’ll lift him at dawn.’

‘A man who beats women?’ I said. ‘You really think that our perp is a man who beats up women?’

I was looking at Dr Stephen. He had his hands stuffed deep inside his pockets. I believed that he could see it too.

‘The perp doesn’t attack women,’ I said.

Dr Stephen still wasn’t looking at me.

‘What did you say, Dr Stephen? Honour. Power. Control.’ I gestured at the face that stared at us from the screen.

They were all looking at me.

Swire was very calm.

‘Did you ever hear of a copper called George Oldfield?’ she said.

I nodded. Everybody had heard of Assistant Chief Constable George Oldfield. He was the head of the hunt for the Yorkshire Ripper. Letters and a tape claiming ‘I’m Jack’ had Oldfield searching the north-east while Peter Sutcliffe was killing women in other parts of the country.

‘I’m not going to play the part of George Oldfield here,’ Swire said. ‘I’m not letting our killer slip through my hands.’

She brushed past me as MIR-1 burst into activity.

But I stayed where I was, looking at the face on the screen.

Honour. Power. Control.

A man who hits women, I thought. Where’s the honour in that?

In the first light of the new day we gathered on a suburban street of modest terraced houses and all I could hear was the sound of my blood. It sounds like the sea, a red rushing sound, when it’s pumped hard enough. And as we crouched below a little garden wall and fiddled with our kit in those last few seconds – adjusting the straps on Kevlars, the firearms officers checking their safety catches, listening to the subdued murmurs of the Airwave radios – that is what mine sounded like.

It told me what was at stake. A young woman’s life. The jobs of all of us who had let her slip away. And something else, something more personal. Because you never know what is on the other side of that door, and what it will do to you.