Lycra padded cycling shorts, black tights and brightly coloured long-sleeved jerseys, headphones clamped to his ears listening to a menagerie of bands like Foals and The Geese, to say that he and Mike Ramsden were several lifestyles apart would be no exaggeration. Karen would like to have considered herself midway between, but she wasn’t sure of that either. Sometimes conversations with Costello beyond police work made her feel as if she were taking classes in how another world lives and failing.

Back in the dead days following New Year and their discovery of Petru Andronic’s identity, the temperatures low, the skies intent on giving new meanings to the word grey, there’d been a glimmer of a breakthrough in the Walthamstow shooting. The bullets taken from the dead youth’s body had been linked to a haul of illegally imported arms and ammunition seized during a raid by officers from the Central Task Force on a warehouse in Deptford. While those officers continued to probe into the identities of those who had both imported the arms and sold them on, Tim Costello was liaising with members of the Met’s Forensic Intelligence Team to trace a possible pattern from other shootings in which guns and ammo from the warehouse had been used.

As for the Wood Green stabbing, it was still a case of speculation and blame. The victim, a youth of fifteen, Derroll Palmer, had no known gang connections, but both of the young men previously arrested and then grudgingly released were members of the Bruce Castle Kings, one of the sets of the Tottenham Mandem gang, and were known to Operation Trident; both had records for minor crime, including assault, yet their alibis had been difficult to break down. One youth had admitted under questioning to being present at the scene, an admission almost immediately withdrawn, his solicitor asserting that the statement had been coerced in an atmosphere of fear and intimidation.

Tell that to the kid laying dead, Karen thought, killed for speaking up when another youth had called his girlfriend, whom he was walking home, a skanky whore.

And of Wayne Simon, missing since the Holloway murders, there was still no clear sign. A possible sighting in Gateshead, nothing more. If the reports were right, farther and farther north. Soon, Karen thought, he’d run out of ground.

She was busy finagling her responses to the latest set of quarterly crime figures that had filtered down from on high, when Ramsden knocked on her door and breezed through.

Sod’s law, a SIM card been found in the last but one bag of gubbins from the Andronic crime scene to be methodically searched, sorted and labelled; missed on a first, preliminary sortie, it had been buried inside a sodden wedge of shredded newspaper, along with rotting sweet wrappers, flattened cigarette butts, a smear of dog shit and a toddler’s missing sock. The original location was noted as the undergrowth to the eastern edge of the pond.

‘We know it’s his? Andronic’s?’

‘Not exactly.’

‘Meaning?’

‘Sent through to Telecommunications Intel. Couple of days back.’

‘And?’

‘Pay as you go.’

Karen shook her head. The problems with pay as you go from her point of view were legion: little or nothing was straightforward, cash sales and so no bills, to say nothing of the possibility of bogus names, bogus addresses, trails that could easily become meaningless when tracing owners. T. Rex now living in Nirvana. Bollocks like that.

‘Any luck,’ she asked, ‘with the registration?’

Ramdsen grinned. ‘Radu Rebeja. Some trumped-up London address.’

‘What’s so funny?’

‘Google him, the guy from Intel said, laughing up his sleeve. Radu Rebeja, the most capped soccer player in Moldovan history. Played most of his career for FC Moscow. Currently Vice President of the Football Association of Moldova. Resident of Chisnau.’

‘Probably not his phone, then?’

‘No. But Andronic aside, how many other Moldovan soccer fans do we think might have been on Hampstead Heath that night, that exact location?’

‘There’s a record of calls?’

‘Intel still working on it. No promises when, snowed under, the usual. So, you know, don’t-’

‘Don’t hold my breath.’

It could lead somewhere, Karen thought, or it could send them up a zillion blind alleys. Too much information sometimes as defeating as too little. She forced herself to concentrate on her paperwork, one eye on the clock, one ear cocked towards the phone, which failed to ring. By the end of the day, there was nothing further about the SIM card, either way.

It was dark out, had been for the best part of three hours already, the false dark you find in big cities; everything shot through with shop lights, car lights, clouds like a stage set, painted on, the sky an unreal blue, like day for night, the horizon washed in an unreal orange glow.

On a whim she stopped off at Ottolenghi on the way home and picked up a portion of roast chicken with chilli and basil, another of mushrooms with cinnamon, and some pear and cranberry upside-down cake for dessert. Treat yourself, girl, and to hell with the expense.

Back at the flat, she poured herself a generous glass of wine, arranged the food on a tray and settled down to watch one of the Swedish Wallandersshe’d recorded from BBC4. Angst and murder on the shores of the Baltic. As long as she could divorce it from reality, her reality — and here the subtitles really helped — she could enjoy the somewhat ramshackle way in which the Ystad police were able, week in week out, to wrap up a case within a mere ninety minutes. And her feelings about Wallander himself, or, rather, the actor who played him, Krister Henriksson, had gone from sheer exasperation — as head of a murder squad he could be about as organised as a sack of kittens — to a resigned pleasure in the way he moved from anger and confusion towards a kind of resolution.

Except where his love life was concerned.

There, she knew how he felt.

A night’s clubbing, a fit body, a good-looking face in a crowded bar, the slip and slither that moved from the dance floor to the taxi to the final fuck, slow and generous or quick and hard, that was no longer enough. As if, since she’d been in her teens and early twenties, it ever really was.

She pushed away the tray, drank down the last of the glass, switched off the TV. Stood at the window for a few moments, staring out. Saw her own reflection imprinted on a terrace of houses opposite, the darkened tree line that marked the edge of Highbury Fields. Along the street, a quick flicker of light from the interior of a parked car illuminated, for the briefest of moments, the shape of a man hunched behind the wheel.

All day now, all through the evening, the scenes which showed Wallander trying with some desperation to bridge the gulf between himself and his grown-up daughter — trying and failing — she had fought to keep her own father at bay. His birthday — late January — little more than a week away. Seventy-three. Seventy-three he would have been had he lived. The car outside, headlights burning, pulled slowly away from the kerb and passed from sight. He had been running, her father, across the street towards where a group of teenage boys was hassling a single, frightened girl. The boys white, the girl light-skinned, mixed race. Jostling, pushing, grabbing, calling names. The girl, her face besmirched with tears, stumbling to her knees and Karen’s father, with a roar of righteous anger, rushing out towards her, towards the surrounding youths, unable, in his haste, to see or hear the van that swung, at that moment, around and into the road, accelerating hard.

Her father’s body, as she had never seen it, other than in her imagination, lifted — hurled — into the startled emptiness of the night air, only to fall, broken, torn, by the pavement’s edge.