'The results are pretty conclusive,' said Logan. 'Someone else killed David Reid. The MO's different, the method of disposal's different, and the victim was female rather than male-'

'Fuck.' It was more of a grunt than a word. Insch had reached the part of the form marked 'Probable Cause of Death'.

'And they can't rule out a fall at this stage,' said Logan.

Insch said fuck again and stomped off down the corridor, heading for the coffee machine by the lifts. He punched in the numbers and handed Logan a plastic cup of pungent, brown, watery liquid with a faint scumming of white froth on the top. 'OK,' he said. 'So Chalmers is out of the frame for the Reid kid.'

Logan nodded. 'We've still got a killer out there, preying on little boys.'

Insch slumped against the coffee machine, making it rock alarmingly. He rubbed a hand across his face again. 'What about the bleach?'

'Applied after death: there wasn't any in her stomach or lungs. Possibly trying to get rid of DNA evidence.'

'Successful?'

Logan shrugged. 'Isobel didn't find any seminal fluid.'

The inspector's shoulders sagged. He stared blankly at the file in his hand. 'How could he do something like that? A wee girl…'

Logan didn't say anything. He knew Insch was thinking about his own daughter, trying not to put the two images together.

At last DI Insch straightened his shoulders, his eyes sparkling dark in his round face. 'We're going to nail this bastard to the wall by his balls.'

'But the head injury? If she fell, if it was an accident-'

'We've still got him on concealing a death, getting rid of the body, attempting to pervert the course of justice, maybe even murder. If we can persuade a jury that he pushed her.'

'Think they'll go for it?'

Insch shrugged, sipping suspiciously at his white coffee with extra sugar. 'No. But it's worth a crack. Only fly in the ointment is forensics. So far there's no sign of the girl having ever been in Chalmers's flat. And it's not like the place had been recently cleaned either, the bedroom was your proverbial pigsty. Chalmers says he's got no idea who the girl is. Never seen her before.'

'That's a shock. What's Sandy the Snake saying?'

Insch glowered in the direction of the interview room. 'Same thing the dirty wee shite always says,' he said, mopping the sweat off his head. 'We've got no evidence.'

'What about the receipt?'

'Circumstantial at best. Says the kid could have been stuffed into that bag after it left Chalmers's property.' He sighed. 'And the little sod's right. If we can't find some solid evidence linking Chalmers to the dead girl, we're screwed. Hissing Sid will tear us to pieces. And that's assuming the Procurator Fiscal wants to risk going to trial. Which isn't likely, unless we get something concrete…' He looked up from his coffee. 'Don't suppose his prints were all over the packing tape she was wrapped in?'

'Sorry, sir: wiped clean.'

It was all wrong. Why would someone go to all the trouble of making sure there were no fingerprints on the tape and then just chuck the body in a bag full of his own rubbish?

'Well,' said Insch, straightening up, and staring back down the corridor towards interview room number three, 'I suppose we shall just have to ignore the complete lack of hard evidence and keep Mr Chalmers banged up. But I gotta admit, I'm getting a bad feeling about this one. I don't think we're going to make it stick…' He stopped and shrugged. 'On the bright side: it'll ruin Sandy the Serpent's day. He won't get to strut his stuff in front of a jury.'

'Maybe another death threat would take his mind off his disappointment?'

Insch smiled. 'I'll see what I can do.'

*

Norman Chalmers was formally arrested and sent back to his cell to appear in court on the next lawful day; Sandy Moir-Farquharson went back to his office; DI Insch went to his dress rehearsal. Logan and WPC Watson went to the pub.

Archibald Simpson's had started life as a bank, the large banking floor transformed into the main bar. The ornate ceiling roses and high cornices were blurred above a fug of cigarette smoke, but the crowd were more interested in the cheap drinks than the architectural details.

As the bar was a two-minute walk from Force HQ it was a popular hangout for off-duty police. Most of the search team were in here. They'd been out in the pouring rain all day, some hunting for forensic evidence on the muddy banks of the River Don, the rest looking for Richard Erskine. Today they'd been searching for a missing child. Tomorrow they'd be looking for a dead body. Everyone knew the statistics: if you didn't find an abducted child within six hours, they were probably dead. Just like three-year-old David Reid, or the unknown girl lying on a slab in the morgue, a big Y-shaped scar running the length of her torso where all her insides had been taken out, examined, weighed, slithered into jars, bagged, tagged and handed into evidence.

They'd spent the first third of the evening talking in serious tones about the dead and missing children. The second third had been spent bitching about the Professional Standards investigation into the leaking of information to the press. Changing their name from Complaints and Discipline hadn't made them any more popular.

And the last third getting seriously drunk.

One of the PCs – Logan couldn't remember his name – lurched back to the table with another round of beers. The constable was entering that stage of drunkenness where everything seemed very funny, giggling as half a pint of lager went all over the table and down the leg of a bearded CID man.

Logan had no intention of being the responsible adult tonight, so he grabbed his pint and walked, a little unsteadily, across to the bandits.

There was a small knot of off-duty officers gathered round a quiz machine, shouting and cheering, but Logan walked right past them.

WPC Watson was standing on her own, jabbing away at a bandit. Flashing lights spiralled round and round the machine's face, glittering and bleeping and dinging away. A half-drunk bottle of Budweiser was clutched in her other hand as she stabbed the flickering buttons, sending the tumblers whizzing round again.

'You look happy,' said Logan as two lemons and a castle appeared on the display.

She didn't even look round. 'Not enough bloody evidence!' Watson hammered the nudge button, getting an anchor for her troubles.

'Have to keep looking,' said Logan, taking a swig, enjoying the warm fuzzy feeling spreading out from the middle of his head. 'Forensics didn't find anything at the flat-'

'Forensics couldn't find shite in a septic tank. What about the bloody receipt?' She stuffed another couple of pounds in the slot and smacked her fist down on the Go button.

Logan shrugged and Watson snarled at the pictures: anchor, lemon, bar of gold.

'We all know he's guilty!' she said, sending the tumblers spinning again.

'And now we've got to prove it. But we wouldn't even have him in custody if it wasn't for you.' Logan had a bit of difficulty with the word 'custody', but WPC Watson didn't seem to notice. He leaned forward and poked her gently in the shoulder. 'That receipt was a damn clever catch.'

He could have sworn she almost smiled as she fed another pound into the machine.

'I didn't spot the Clubcard points. You did that.' She didn't take her eyes off the flashing lights.

'And I wouldn't have if you hadn't found the receipt in the first place.' He beamed at her and took another drink.

She took her eyes off the machine's flashing lights to watch him sway slightly, almost in time with the music. 'What happened to "one four times a day, not to be taken with alcohol"?'

Logan winked. 'I won't tell anyone if you don't.'

She smiled at him. 'Babysitting you is going to be a full time job, isn't it?'