Michael Robotham - Shatter

I go straight to the map on the wall. A second white pin is stuck alongside the first. Oliver is trying to explain his reasoning.

‘Yesterday’s anomaly happened at 3.07 p.m. The mobile was turned on for fourteen seconds but he didn’t make a call. Later, he transmitted a photograph from the same phone to your wife’s mobile. Afterwards, he left the handset on a bus.’

He pulls the image up on screen showing Charlie with her head encased in tape and a hosepipe in her mouth. I can almost hear the rasp of her breath through the narrow opening.

‘The second anomaly was this morning, just before he sent another photograph- the picture of your wife. It explains things.’

Gideon knew police could trace a mobile every time he turned it on. He didn’t make mistakes. In each case he turned on the mobile phone for a reason. Two signals. Two photographs.

‘Can you trace the signals?’ I ask.

‘I was struggling when there was only one, but now it might be feasible.’

I sit alongside him, unable to comprehend most of what he’s doing. Waves of numbers cross the screen as he quizzes the software, overrides error messages and circumvents problems. Oliver seems to be writing the software as he goes along.

‘Both signals were picked up by a ten metre GSM tower in The Mall, less than half a mile from the Clifton Suspension Bridge,’ he says. ‘The DOA points to a location west of the tower.’

‘How far?’

‘I’m going multiply the TOA- Time of Arrival- with the signal propagation speed.’

He types and talks, using some sort of equation to do the calculation. The answer doesn’t please him.

‘Anywhere between two hundred and twelve hundred metres.’

Oliver takes a black marker pen and draws a large teardrop shape on the map. The narrow end is at the tower and the widest part covers dozens of streets, a section of the Avon River and half of Leigh Woods.

‘A second GSM tower picked up the signature and sent a message back but the first tower had already established contact.’ Again he points to the map. ‘The second tower is here. It’s the same one that carried the last mobile call to Mrs Wheeler before she jumped.’

Oliver goes back to his laptop. ‘The DOA is different. North to north-east. There’s an overlapping connectivity.’

The science is beginning to lose me. Rising from his chair again, Oliver goes back to the map and draws a second teardrop shape, this one overlapping the first. The common area covers perhaps a thousand square yards and a dozen streets. How long would it take to doorknock every house?

‘We need a satellite map,’ I say.

Oliver is ahead of me. The image on his laptop blurs and then slowly comes into focus. We appear to be falling from space. Topographical details take shape- hills, rivers, streets, the suspension bridge.

I walk to the door and yell, ‘Where’s the DI?’

A dozen heads turn. Safari Roy answers. ‘She’s with the Chief Constable.’

‘Get her! She has to organise a search.’

A siren wails into the afternoon, rising from the crowded streets into a coin-coloured sky. This is how it began less than four weeks ago. If I could turn back the clock would I step into that police car at the university and go to the Clifton Suspension Bridge?

No. I’d walk away. I’d make excuses. I’d be the husband Julianne wants me to be- the one who runs the other way and shouts for help.

Ruiz is alongside me, holding on to the roof handle as the car swings through another corner. Monk is in the front passenger seat, yelling commands.

‘Take the next left. Cut in front of this bastard. Cross over. Go round this bus. Get that arsehole’s number plate.’

The driver punches through a red light, ignoring the screeching brakes and car horns. At least four police cars are in our convoy. A dozen more are coming from other parts of the city. I can hear them chattering over the two-way.

The traffic is banked up along Marlborough Street and Queens Road. We pull on to the opposite side of the road onto the footpath. Pedestrians scatter like pigeons.

The cars rendezvous in Caledonia Place alongside a narrow strip of parkland that separates it from West Mall. We’re in a wealthy area, full of large terraces, bed amp; breakfast hotels and boarding houses. Some of them are four storeys high, painted in pastel shades, with outside plumbing and window boxes. Thin wisps of smoke curl from chimneys, drifting west over the river.

A police bus arrives carrying another twenty officers. DI Cray issues instructions, unshakeable amid the melee. Officers are going door to door, talking to neighbours, showing photographs, making a note of any empty flats and houses. Someone must have seen something.

I look again at the satellite map unfurled across a car bonnet. Statistics don’t make science. And all human behaviour cannot be quantified by numbers or reduced to equations, no matter what someone like Oliver Rabb might think. Places are significant. Journeys are significant. Every excursion or expedition we take is a story, an inner narrative that we sometimes don’t even realise we’re following. What was Gideon’s journey? He boasted that he could melt through walls, but he was more like human wallpaper, able to blend in and become simply background while he watched houses and broke into them.

He was there when Christine Wheeler jumped. He whispered in her ear. He must have been somewhere close. I look at the terraces, studying the skyline. The Clifton Suspension Bridge is less than two hundred yards to the west of here. I can smell the sea stink and gorse. Some of these addresses are likely to have a view of the bridge from the upper floors.

A man rides past on a bicycle with elastic around his trouser legs to stop the fabric getting caught in the chain. A woman walks her black spaniel on the grass. I want to stop them, grasp them by the upper arms and roar into their faces, demanding to know if they have seen my wife and daughter. Instead, I stand and study the street, looking for something out of the ordinary: people in the wrong place, or the wrong clothes, something that doesn’t belong or tries too hard to belong or draws the eye for another reason.

Gideon would have a chosen a house, not a flat; somewhere away from the prying eyes of neighbours, isolated or shielded, with a driveway or a garage so he could take his vehicle off the road and move Charlie and Julianne inside without being seen. A house that is up for sale, perhaps, or one that is only used for holidays or weekends.

I step across the muddy patch of grass and begin walking along the street. The trunks of trees are wreathed in wire and the branches shiver in the wind.

‘Where the hell are you going?’ yells the DI.

‘I’m looking for a house.’

Ruiz catches up to me and Monk is not far behind, having been sent to keep us out of trouble. I keep looking at the skyline and trying not to stumble. My cane click-clacks on the pavement as I head down the slight hill past a row of terraces and turn into Sion Lane. I still can’t see the bridge.

The next street across is Westfield Place. A front door is open. A middle-aged woman is sweeping the steps.

‘Can you see the bridge from here?’ I ask.

‘No, love.’

‘What about the top floor?’

‘The estate agent called it “glimpses”,’ she laughs. ‘You lost?’

I show her the photographs of Charlie and Julianne. ‘Have you seen either of them?’

She shakes her head.

‘What about this man?’

‘I’d remember him,’ she says, when the opposite is probably true.

We keep moving along Westfield Place. The wind is whipping up leaves and sweet wrappers that chase each other along the gutter. Abruptly I cross the street to a brick wall with stone capping.