'What is it?' DI Insch.

Logan risked a sniff at the open evidence bag. 'Unless I'm verysmuch mistaken, it's a wankerchief. Your man probably stood here to watch the place burn, listen to them scream as they died, tossing himself off to the smell of roasting human flesh.'

Insch wrinkled his nose. 'PC Jacobs was right: you are a morbid bastard.'

The woman next door was drunk again. Out in her back garden with the radio blaring Northsound One, staggering about in time to the music, swigging from a bottle of wine, not caring that it was pouring with rain. She just wasn't right in the head, that much had been clear from the moment they'd moved in: her and her strange, pointy-faced boyfriend and their huge black Labrador. He was a lovely dog, a great slobbery lump of affection, but there had been no sign of him for nearly two weeks. The woman said he'd probably run away. That he was an ungrateful bastard and didn't deserve a home.

She said the same thing about her boyfriend.

Shaking her head, Ailsa Cruickshank turned away from the window and finished making the bed. The woman next door didn't care that her dog was missing, so it had been up to Ailsa to make up little laminated posters and fix them to the lampposts and shop windows all over Westhill. Never let it be said that she didn't do her bit.

Outside, the noise got even worse as the woman started singing along with some rap 'song' with the swearwords bleeped out. Only the woman next door wasn't censored like the,radio; she roared out the obscenities at the top of her voice. Shuddering, Ailsa went through to the lounge and turned her own television up loud. The woman wasn't right in the head: everyone knew it – she was on tablets. Abusive, drunken, violent; she was every neighbour's worst nightmare. How were Ailsa and Gavin supposed to start a family with that harpy screeching and yelling next door? Gavin and the woman were at loggerheads the whole time, arguing over the noise, the language, calling the police… Ailsa shook her head sadly, watching as her neighbour slipped on the rain soaked grass, clanged her head off the whirly washing line and lay there crying for a minute, before swearing and screaming, hurling her wine bottle to explode against the fence. Ailsa shivered: she was going to end up hurting someone; she just knew it.

Union Grove looked a lot more posh than it actually was: a long avenue of granite tenements branching off Holburn Street in the city's west end, lined with parked cars and the occasional tree. Brooding in the rain. The address they had for Graham Kennedy was a top-floor flat in one of the grubbier buildings, the communal front door caked with layers of blue and green blistered paint. The street was empty, except for a trio of small kids standing in a doorway across the road eating crisps, watching the police with interest. A patrol car, Alpha Four Six, was already sitting out front as PC Steve parked Insch's Range Rover half a mile from the kerb, getting an earful from the inspector for his efforts. Blushing furiously he shoogled the car forwards and backwards until the pavement was within walking distance. He was told to stay behind and watch the spaniel.

On the inspector's orders Alpha Four Six had brought a family liaison officer, a nervous young man with a permanently runny nose and two left feet. After a damp handshake he hurried after Insch and Logan into the building, out of the rain, confessing on the way that this was his first case. Insch took pity on the man and gave him a fruit pastille, for which he was obscenely grateful. The stairs up to the top floor were covered in a shabby, threadbare carpet, the walls in peeling flock wallpaper. Everything had that unmistakable, stinging reek of cat piss. Flat number five: brown door, fading brass number screwed to the wood and a plaque bearing the legend 'Mr amp; Mrs Kennedy'.

'Right,' said Insch, offering round the fruit pastilles again, 'this is how it works: we go in, I announce the death.' He pointed the packet of sweets at Logan. 'DS McRae has a bit of a poke about while the family are still in shock.' The pastilles came round to point at Mr Runny Nose. 'You make the tea.' The young man looked as if he was about to complain at being relegated to tea-boy, but Insch cut him off at the pass. 'You'll get to use all that touchy-feely crap they taught you once we've gone. Till then: I take milk, two sugars and DS McRae's just milk. OK?'

The family liaison officer mumbled 'OK' as Logan rang the bell. And then they waited. And waited. And waited…

Finally a light blossomed in the fanlight above the door.

Sounds of shuffling and an old lady's voice saying, 'Who is it?'

'Mrs Kennedy?' Insch held his warrant card up in front of the spy hole. 'Can we come in please?' The chain rattled and the door opened a crack, revealing a weather-beaten face with big glasses and a grey perm. She eyed the policemen on her doorstep with concern. There had been a lot of break ins in the street over the last couple of years – one old lady had ended up in hospital. The inspector handed her his warrant card and she held it at arm's length, peering at it over the top of her spectacles. The inspector's voice was soft: 'Please, it's important.'

The door closed, there was some rattling and then it opened all the way, exposing a grubby hallway that ran right to le t, peppered with seventies-style plywood doors. She led them into a large lounge done up in faded-yellow wallpaper with orange and red roses on it. A pair of rickety couches sat in the middle of a swirly-patterned carpet, wood and fabric groaning alarmingly as Insch sat down and the old lady fussed over a large orange tabby cat the size of a beach ball.

'Mrs Kennedy,' said Insch as the huge cat hopped up onto the coffee table and started licking its bum. 'I'm afraid I have some bad news for you: it's your grandson, Graham. He was one of the people who died in the fire on Monday night.

I'm sorry.'

'Oh my God…' She clutched at the cat, dragging it away from its ablutions. It sagged into her lap, legs stuck out at right angles, like an over-inflated set of ginger bagpipes.

'Mrs Kennedy, do you know anyone who might have wanted to hurt your grandson?'

She shook her head, her eyes filling up with tears. 'Oh God, Graham… You shouldn't have to bury your grandchildren!'

The family liaison officer was dispatched to make the tea while Logan surreptitiously excused himself and had a quick look round the flat. It was a big place, shabby, but nothing a couple of coats of paint wouldn't fix. He poked from room to room, peering under beds, into wardrobes and drawers. All the time the muted tones of DI Insch and the sobbing woman leaked through the closed lounge door.

Kitchen, bathroom, spare room, Mrs Kennedy's bedroom with its certificates of merit and group photographs of school children… Only one of the doors leading off the hallway was locked: from the look of things the stairs up to the attic, but Graham's room was open, the bed made, the clothes all neatly folded and put away, all the socks paired off, not so much as a porn mag under the bed. It didn't fit the image Logan had of Graham Kennedy from reading his criminal record. Minor assault, breaking and entering, possession with intent… Small stuff mostly, but it all added up. He got back to the living room just in time to hear DI Insch say, 'We'll let ourselves out.' Leaving the family liaison officer behind.

They stopped at the communal front door, looking out at the rain drumming on the car roofs. 'Well?' asked Insch.

'Nothing. Place is clean as a whistle. If he kept any gear, he wasn't doing it at granny's house.'

Insch nodded and pulled out the last of the fruit pastilles, munching sadly. 'Poor cow: she raised him pretty much single-handed. Graham's parents died when he was three, then her husband snuffs it a year later.' He sighed. 'That's her whole family gone now.'