This time, there was more than just a desire to have sex, although this came high on the list. I was attracted to Carla in a way I'm not used to. The last time I'd had a feeling like this was when I'd started going out with Danny's sister, and that had been a long time back.

She stayed for about another twenty minutes. I was desperate to go to the toilet for most of the conversation but held back, not wanting to give her an excuse to realize that she ought to be on her way home. We chatted about this and that, mainly to do with our respective jobs, and I found her an interesting and intelligent talker. She was single as well, which helped. Divorced with no kids, she said that most of the time she was married to her work. I told her I knew the feeling.

I kept looking for an opportune moment to ask her out but one never came, or maybe it's more accurate to say that my nerve let me down. I mean, she was a serious career woman with an air of authority about her more suited to a politician than to social services, and I was like a schoolboy in love for the first time with feelings that were more seventeen than thirty-seven.

When she'd finished her drink, she stood up and offered me a hand to shake. 'I really must be going, Mr Milne. It's been very pleasant, it's just a pity that the reason we've been brought together is so tragic.'

I stood up and shook, squeezing her hand tightly. 'Unfortunately, that's the way it goes sometimes. Well, it was nice to talk to you, Ms Graham.'

'You may as well call me Carla.'

'Well then, I insist you call me Dennis.' It sounded a really shite name when I said it like that. Really unsophisticated. Like Wayne, or Eric. For a moment I wondered why I'd never changed it to something better. Even Zeke would have been an improvement.

She smiled. 'Well, Dennis, I hope the investigation goes well.'

That was my opportune moment, but I bottled it. 'I'm sure it will. I'll be in touch if there's anything else we need. And obviously, as I said earlier-'

'I'll definitely let you know if any of the girls goes missing, but, as I told you, it does happen a lot, and there's usually an innocent explanation, if I can use a word like that.'

'Sure, I understand.' I finished my drink. 'Let me walk you to your car.'

'There's no need. It's only parked round the corner. I'd offer you a lift but I've got a very early start.'

'No problem, I understand.' At least my bladder would thank me.

I sat back down and she turned to go, then turned back again. 'Oh, one last thing. Tell me, how did you get Anne to go back to the hostel?'

'I bribed her.'

'With what?'

I felt a bit sheepish admitting what I'd done, but did it anyway. 'I paid her to go back. I gave her some money in lieu of any earnings she would have got by staying out there.'

I wasn't sure if this would please her or not. Probably not. But, surprisingly, she looked at me with what I thought was a measure of respect. 'You are a sensitive soul, Dennis.' She smiled. 'I'm almost certain it was a futile gesture. Girls like Anne aren't going to be redeemed suddenly, but I appreciate your concern.'

'Thanks,' I said, and watched her as she disappeared out of the door.

It was ten past nine and I was tired, a long way from home, and desperate for a piss. The evening's events had at least given me some insight into the type of world these girls inhabited, and the type of people out there preying on them. But whether it helped move the case on or not, I wasn't sure.

'We're going to charge the pimp,' Malik said excitedly as I walked into the incident room at a quarter to nine the next morning.

The place was buzzing, as is always the case when you've had a result, and most of the detectives who'd been involved were sitting about looking pretty pleased with themselves, although I couldn't see Welland anywhere, and Knox wasn't in his office. Charging Mark Wells and convicting him were two different things, of course, but it sounded like there was definitely room for a lot of optimism. Clearly there'd been some sort of significant breakthrough in the past few hours.

'You missed all the action, Dennis,' DS Capper said loudly. 'Where were you?' Capper was at his desk along with two of his DC cronies, one of whom was my last sexual conquest – if you can count two faked orgasms as a conquest.

I stopped in front of them. 'What happened, then? Did he confess?'

'He will do. Now that we've got the shirt he was wearing when he killed her. Covered in her blood.'

Capper looked far too self-satisfied for my liking. It was hard enough speaking to him when he was having a bad day, well nigh impossible when he was having a good one. I said to the room in general that it was a piece of very good news, smiled as if I'd just been told I had a really big cock, and sat down at my desk. Malik followed me and seated himself on the other side.

I looked at him with surprise. 'Shit, that all happened fast. When did you hear about it?'

'I saw it on Teletext first thing this morning and came straight in. That was a couple of hours ago.'

'Who found the shirt, then?'

'We got a tip-off. Apparently one of Wells's girls called in last night and said that Wells had admitted to her that he'd killed Miriam Fox and dumped the clothes nearby. They did another search of the area and found the shirt. It went off to forensics in the early hours of this morning. The preliminary tests show an exact match between the blood on the shirt and Miriam Fox's blood.'

'That was quick.'

'Time's of the essence, isn't it? By lunchtime we'll have already had him for twenty-four hours.'

'So it's not a done thing yet?'

'No, but it looks like it's going to go that way. It's definitely the murderer's shirt and we've got a good link between it and Wells.'

'Who was the caller? Did she give a name?'

Malik shook his head. 'No, but you can't blame her, can you? She's not going to want any publicity.'

I nodded slowly and lit a cigarette. It was a fair point.

'What's up, Sarge? You don't look totally convinced.'

I yawned. 'Nah, I'm just tired. I didn't sleep too well last night.' I had a bit of a hangover as well. I'd left the pub shortly after Carla had gone but had stopped off at the Chinaman on the way home for a quick one. Unfortunately it had turned into a slow three. 'You wouldn't do an old man a favour, would you?'

'That old man being you?'

'That's right.'

'What is it you want?'

'A bacon sandwich and a nice cup of tea.' He gave me a dirty look. 'Please, Asif, I wouldn't ask if it wasn't an emergency.'

'You've got to change your diet, Sarge. You eat nothing but crap.'

'Well, get me an apple as well.' I fished into the pocket of my suit and brought out two pound coins. 'Please. Call it a personal favour. I won't ask again, I promise.'

He took the money reluctantly, checking that no-one was watching, and got up. 'This is a one-off, Sarge. Remember that. It's only because you look so bloody rough that I'm agreeing.'

'Your pity will be rewarded,' I told him piously.

When he'd gone, I started to think about this new development. I hadn't slept well because I'd been thinking about my conversation with Anne and the possibility that there was some sort of serial killer on the loose targeting underage prostitutes. It was a flight-of-fancy theory, really. Though they make ideal fictional villains and endless fodder for real-life documentaries, in reality serial killers are as rare as dinosaur turds. If there were more than two operating in this whole country of close to sixty million people at any one time, I'd be extremely surprised. But I suppose these things do occasionally happen, and if such a man was at work he'd picked the right sort of place and the right sort of victims to keep himself concealed. The only thing was, if Molly Hagger and any other girls had fallen victim to this man, where were the bodies? And why was Miriam Fox's left in such an obvious location?