The caretaker remembered seeing someone, almost certainly Maddy, heading off along the lane towards Crouch Hill, the opposite direction to the one she would have taken if she were going directly home. But then Crouch Hill would have quickly led her down to the Broadway and bars, restaurants and cafes aplenty, where she could either have been meeting someone by arrangement or meaning to have supper or a drink alone. Except that none of the waiters or bar staff recognised Maddy as having been amongst their customers that evening.

So had she been attacked almost immediately after leaving the centre – risky, with others still presumably within earshot – or had she, indeed, walked down to the Broadway and later returned by the same route? And was her attacker some stalker, as yet unknown, someone waiting for her, out there amongst the shadows, waiting for his chance? Or had it been a random act, Maddy's misfortune to be in the wrong place at the wrong time?

Too many questions still unanswered.

'Phone, ma'am,' said one of the office staff, interrupting her train of thought. 'For you.'

'Who is it?'

'A Frank Elder? He's called several times before. Something about Maddy Birch, apparently.'

Karen sighed. It was way past seven already. Staff pulling in overtime. What she wanted was to go home, open a bottle of red and drink the first glass while she soaked in a hot bath.

'Okay.'

Karen perched on the end of a desk, one foot resting on the seat of a chair. Across the room she could see Lee Furness slowly scrolling down through a list of names on the computer.

'Hello, this is DCI Shields.'

'Frank Elder.'

'I believe you've got some information about Maddy Birch.'

'Not information exactly.'

'What then?'

'I worked with her. Maddy. In Lincolnshire.'

'How long ago?'

A pause. 'Eighty-seven, eighty-eight.'

'And you were what? Close? Close colleagues? What?'

'Close, I don't know. Not really. We worked together, that's all. I was just wondering how things were going. The investigation.'

'How things are going? What do you think this is? Crimewatch?'

'I'm sorry, I was given your name…'

'Look, maybe you should talk to the press office. If anyone. Just hold on and I'll get you transferred.'

'No, it's okay. It doesn't matter. I'm sorry to have taken your time.'

Karen heard a click as the phone was replaced.

Just about the last thing she needed, some old geezer with too much time on his hands.

13

'Bloody shame,' Linda Mills had said, when she heard of Maddy's death.

'Shocking,' Trevor Ashley agreed.

'Now we'll never get the chance to talk to her again.'

Ashley looked at her sharply, but kept his counsel.

Things moved slowly on. It was the second week of December, some eight weeks since the inquiry into the Grant shooting had opened, three, give or take, since Maddy Birch's body had been found off Crouch Hill.

Despite the often open hostility of many of those who were interviewed, the inquiry had kept, doggedly, to the rails. Linda, frustrated by their lack of progress, had become grimmer and more short-tempered even as her superior seemed to become more avuncular and benign. But for all of their probing, questioning, reconstruction, after almost two months there was no proof of any wrongdoing, no reprimand, no charge.

That Grant was a major villain was beyond doubt, the presumption that he was close to fleeing the country well-founded, as was the supposition that he would be armed. The logistics of the raid itself left something to be desired and a recommendation to review planning procedures would be attached as a codicil to the final report. At base, however, the facts spoke for themselves: Grant had fatally wounded one officer and if Mallory had not acted as he had there was every reason to believe he would have killed another.

End of story.

Wrap it up, dot the i's and cross the t's, sign your name and leave.

Honour satisfied and justice seen to be done.

When it came down to it, whatever her lingering doubts, Linda Mills would be glad to shake the dust of London off her feet. Ashley had warned her what it would be like, that she would feel isolated and embattled and regarded as the enemy, and he'd been right. The experience, though, had been something she wanted, something to add to her profile, broaden her CV.

'I owe you both a vote of thanks,' the Assistant Commissioner said in his office. 'A difficult task professionally executed.'

'I owe you a slap-up dinner,' Ashley said later, broad grin on his face. 'Prawn cocktail, steak and chips, black forest gateau, the whole bit.'

'You owe me,' Linda told him, 'a sight more than that.'

The day after the final report had been delivered to the printer, the day before the bound copy was delivered to the Assistant Commissioner, she had been sitting on the low steps outside the Portakabin that had remained their temporary home, smoking a longed-for cigarette.

She had scarcely heard Mallory as he crossed the car park, light of foot, only glancing up at the last moment and dropping her cigarette hastily down, like a fourth-former caught behind the legendary bike sheds.

'Don't worry,' Mallory said. 'Your secret's safe with me.'

As she stood up, Linda squashed the smouldering butt beneath her foot.

'We're all guilty of something, big or small,' Mallory said. 'Wouldn't be human, else.' The smile lingered in his eyes. 'Here,' he said, taking a packet of Benson & Hedges from the side pocket of his blazer. Blue blazer and brown trousers. Highly polished shoes. 'Have one of mine.'

'No, thank you, sir.'

Mallory shrugged and produced a lighter. 'I was hoping I might bump into you,' he said, the smoke drifting towards Linda's face.

'Sir?'

'Before you shut up shop and turn tail for Hatfield…'

'Hertford, sir. It's Hertford, actually.'

'Hertford, Hatfield, Hitchin – all the same. Penny-ante little market towns with scarce a pot to piss in. Low-grade drug dealing and a handful of public-order offences of a weekend the best you can hope for.'

Linda nodded noncommittally.

'Always the worry,' Mallory said, 'let one of your kind out of the box and you never know which way they'll jump. Chancy that. Like letting off a firework in the middle of the bonfire, Guy Fawkes Night. Any bloody thing could happen.' Almost imperceptibly, he moved closer towards her. 'Someone could even get burned.'

For a moment, maybe more, his eyes bore into her, before, with a deft smile, he stepped away.

'But you now,' he said, 'no need to worry by all accounts'. Everything by the rules. Light the blue touch-paper and stand well clear.'

'You've seen the report,' Linda said, challenging.

'Place like this, difficult to keep things under wraps.'

'But you have seen it. A copy at least.'

'You think so?'

She knew it. He'd read it, relished and relaxed. Exonerated in Times New Roman, double spaced. Her signature at the bottom.

'You may think,' Mallory said, 'I owe you a favour.'

'Not at all, sir. We did our job, that's all. Just like you said. And I was only the junior officer, after all.'

'Junior, maybe, but always pushing hardest, eager for the truth. Gave poor Maddy Birch a rough ride, from what I hear. Had her up against the ropes. To mix a metaphor or two. Still, no gain having your card marked by a fool and you're no fool.'

A wink and a smile and he was on his way, leaving Linda wondering if there wasn't something crucial that they'd missed.