The Man on Hackpen Hill Read online

  ‘Polyalphabetic substitution?’ Strover asks.

  Silas gives her another look. Five bonus points to Swindon.

  ‘Precisely.’

  The mathematician doesn’t bat an eyelid at Strover’s knowledge. Silas knows he shouldn’t either. It’s what comes from a university education.

  ‘The basic idea behind the cipher is to deny codebreakers the opportunity to do frequency analysis on certain letters such as “e”, which is the most commonly occurring letter in English,’ she continues. ‘The weakness is the key word. We don’t need to know exactly what it is to unlock the code but if we know its length, we can break the ciphers individually by calculating how many different alphabets have been used.’

  ‘And that’s what you’re working on?’ Silas asks. Despite her lack of instant answers, Silas likes the professor, the way she doesn’t talk down to him and Strover.

  ‘Correct,’ she says. ‘We’re currently using something called the Index of Coincidence to determine the key word length. We’ve also been in touch with some American colleagues at the National Security Agency in Maryland – the Vigenère cipher was once used to encrypt part of a coded message on a sculpture at the CIA headquarters in Langley, Virginia. Its unveiling was a challenge to cryptanalysts everywhere – and the guys at NSA beat everyone to it back in the 1990s.’

  ‘Keep an open mind about BZ,’ Silas says. ‘Maybe the letters will turn out to be its formula.’

  ‘Absolutely,’ the mathematician says. ‘They could well be numbers or letters or a mix of the two.’

  ‘And any idea how long it might take to decrypt this Vigenère cipher?’ Silas asks.

  ‘The guys at NSA used a pen and paper and took forty-eight hours,’ she says. ‘We’ve got supercomputers these days so it shouldn’t be long. Having said that, there’s one part of the CIA sculpture code that still hasn’t been deciphered by anyone – more than forty years after it was made.’

  54

  Bella

  For a moment, Bella wonders if Jim has hung up. Or has she just shocked him into silence with her revelation about Erin?

  ‘Jim?’ Bella asks, glancing around the kitchen. She mustn’t talk for long on her mobile. It’s too risky.

  ‘I’m here,’ he says, his voice barely audible. ‘How do you know this?’

  ‘I know because she’d covered her arms in feather tattoos – like the body they found. She had a rook behind her ear too. I thought she was recovering in hospital but…’

  She can’t go on any longer and starts to sob again.

  ‘I’m so sorry,’ Jim says, struggling to find the right words. ‘I had no idea. I wish I… I wish I was there with you.’

  ‘You really need to tell me what’s going on here,’ Bella pleads. She’s played her trump card, told him about Erin. There’s nothing more she can say to persuade him to reveal all.

  ‘I will, I promise.’ He pauses again. ‘Did your friend… did Erin ever act strangely? Out of character? Like she was tripping or something?’

  Jim’s voice has changed, become more matter-of-fact. Analytical.

  ‘Why?’ Bella asks, wondering how he knows, dreading what he might say next. Erin was queen of strange at college, always tripping out.

  ‘These crop circles, they’re complex, coded patterns,’ he says. ‘No one seems to know what they are. The hexagons hint at molecular structures and the wheels, the binary sequences… I’m sure they contain their chemical formulas. I’ve only seen pictures of the second circle briefly, the one Erin was found in, but I think I know what it means.’

  ‘You do?’ Bella asks. Why hasn’t he told her this before?

  ‘It looks like a representation of lysergic acid diethylamide. LSD. Acid. I think the first circle represents BZ, a psychochemical weapon developed by the Americans in the 1960s and last used by Assad in Syria. The third one I’m sure is VX, the most potent nerve agent ever made. All three are kept at Porton Down.’

  This time it’s Bella’s turn to remain quiet, thinking of Erin’s body lying in the flattened wheat. Erin dropped a lot of acid at college.

  ‘You still there?’ Jim asks.

  ‘Erin had issues,’ Bella says quietly. ‘Took loads of drugs. But she’s never been to Porton Down, never had any dealings with a place like that. She grew up in Dublin and London and then spent three years at Oxford on a full scholarship.’

  ‘I’m not saying she’s been to Porton,’ Jim says. ‘It doesn’t always work like that.’

  ‘What doesn’t?’ Bella asks, unable to contain her frustration.

  ‘Have you rung the police?’ Jim asks, ignoring her question. ‘About Erin?’

  ‘Yes, I mean no,’ she says. She won’t be able to cope if he’s cross with her. ‘I rang Crimestoppers but they don’t—’

  ‘Did you leave your name? Tell them Erin’s? It’s important you tell me, Bella.’

  He sounds more concerned than angry. ‘Not my name, no,’ Bella says, again regretting that she’d made the call to Crimestoppers. ‘I just said that my friend was called Erin.’

  She can hear Jim sigh. ‘That might have been a mistake,’ he says. ‘A big mistake. You’ve got to be very careful with these people. Believe me, Bella. I know what I’m talking about. Take the battery out of your phone as soon as we hang up.’

  ‘I’ve been doing that,’ she says, looking down at her mum’s scribbled note on the hall table.

  ‘Can you get down to Swanage?’ Jim asks.

  ‘Me? Swanage?’

  She’s only just returned from Wiltshire, but she has no desire to remain in this empty house. She glances at the hall table again. At the car keys. If her mum can drop everything for a romantic tryst with Dr Haslam, she can go to Swanage. Her mum never uses the car in London. Bella would prefer to take the train but it will take too long. Her only other worry is Jim. Can she trust him? He seemed genuinely shocked by Erin’s death but how much does he really know about the crop circles? What if he was involved in their making in some way?

  ‘I might not have much longer,’ Jim says. ‘They’re here, in the town, but they won’t find me. I know this place better than them, grew up here. Bring your laptop – and the USB. And turn off your satnav. Don’t use anything that could be hacked to track you. Call me when you get near and I’ll tell you where to meet.’

  55

  Silas

  ‘Play it again,’ Silas says, eyes fixed on the TV screen. He’s back in the estate manager’s office at the Great Western, watching CCTV footage from the front of the hospital. The manager called him fifteen minutes ago, asking him to come over as quickly as he could. Silas obliged, happy to avoid another Zoom call. The site is still in full lockdown. Uniforms everywhere, patrol cars lined up at the front of the hospital, police helicopter overhead.

  The manager leans forward to play the footage again. It’s taken from earlier in the day, when the two men involved in the Range Rover accident discharged themselves from the hospital. One of them has his arm in a sling, the other is wearing a neck brace. Silas watches as they walk out of the main entrance and stand in the pick-up area. Ten seconds later, after a lot of glancing around, they board a bus that’s swooped up through the car park.

  ‘What else?’ Silas asks, turning back to the estate manager. It’s good, but Silas senses there’s more.

  ‘We’ve only just seen this, but I’m sure it’s him,’ he says.

  Silas can detect the suppressed excitement in his voice, trying to remain professional.

  Again, the footage is from earlier. Silas watches as a man exits the front entrance. It’s the ‘doctor’ who passed them in ICU. He walks over to the same pick-up area, glancing at his watch. After two minutes, he pulls out his phone, looking around him again. He then makes a call, talking animatedly, before walking off camera.

  ‘We pick him up again here on another camera, running around the back of the building,’ the estate manager says.

  The man is heading towards A & E and a queue of ambulanc
es.

  ‘Whoever was meant to collect him at the front didn’t turn up,’ Silas says, sitting back.

  This is good, the sort of break they need.

  ‘It gets better,’ the estate manager says. ‘We’ve just found this.’

  Silas leans forward as the manager plays a third piece of footage.

  ‘Where’s that?’ Silas asks, watching as the man uses his pass to enter through a door.

  ‘It’s the lower ground floor – staff entrance.’

  ‘How long ago was this?’

  ‘Ten minutes?’

  ‘So he could still be on site?’ Silas asks, mind racing.

  ‘There are two visitor lifts to the lower ground floor, two service, one clinical – we’ve isolated all five. And I’ve got my security guards on every exit. He hasn’t come out of any of them – we’ve checked the footage.’

  ‘And what’s down there?’ Silas asks.

  ‘The training academy, facilities management, plant rooms,’ he says, pausing. ‘And the mortuary.’

  Silas looks up. He had been allowed as much time as he wanted to stay with his father after he had died. But as soon as Silas had left, his body was washed and taken straight down to the mortuary. Mel had told him later. ‘Where is this entrance then?’ he asks.

  ‘Just beyond A & E.’

  ‘Strover?’ Silas calls out through the half-open door.

  ‘Yes, sir?’ she says, coming off the phone as she returns to the room.

  ‘We need four uniforms now.’

  56

  Bella

  Bella takes one last look around the house, in case she’s forgotten anything, and heads for the front door with her bag. She’s packed enough clothes to stay a few days in Swanage. Jim sounded stressed and she has no idea what he has in mind. All she knows is that she needs to get to the bottom of what happened to Erin and Jim is currently her only lead.

  The landline rings just as she opens the front door. Bella puts down her bag and walks back into the kitchen. Should she answer it? What if it’s Dr Haslam? She picks up. Gladys, from the migrant centre.

  ‘Hello?’ Bella says nervously.

  ‘Is that Anne-Marie?’

  ‘No, it’s Bella.’

  ‘Bella! You two sound so similar it’s spooky.’

  ‘Do you know where Mum is?’ Bella asks, interrupting her.

  ‘Trying to get hold of her myself,’ Gladys says. ‘We down two members of staff today and it’s our big early dinner in an hour. Right now it’s just me and the cat and she ain’t so good at serving the soup.’

  Gladys is one of the migrant centre’s larger-than-life heroes, always upbeat and full of laughter. She’s the de facto boss of the place, loud and maternal, and loved by migrants and co-workers alike.

  ‘Do you know where she might be?’ Bella repeats, failing to disguise the emotion in her voice. The fact that Gladys has been trying to get in touch with her mum too makes Bella doubt whether she’s with Dr Haslam.

  ‘What happened, girl?’ Gladys asks.

  ‘I don’t know where she’s gone,’ Bella says.

  ‘Listen, you know what Anne-Marie’s like. She’s probably on her way over now, met someone in the street and started to chat. Cha, always ah chat.’

  Gladys is right. Her mum talks to anyone and everyone. Bella’s just been overreacting, letting her imagination get carried away. She’s having a quick drink with Dr Haslam before heading over to the migrant centre. But then she remembers the scribbled handwriting, the way the note was tucked away under the carving.

  ‘You’re probably right,’ Bella says, unconvinced.

  ‘I know I’m right. And if she’s not with you at home, she’s on her way. In the meantime, I was thinking… Might you be able to drop by and help out round here? In case she really has forgotten it’s our big day?’

  Bella glances at her watch. She worked in the kitchen when she first came back from uni, helped lay out the tables and chairs, enjoyed the camaraderie, but she should be heading to Swanage. Her best friend’s dead and she needs to know why. On the other hand, if her mum’s on her way over there, it would be good to see her, thank her for the typewriter, talk to her about Erin, ask about borrowing the car. And it might help to take Bella’s mind off things, allow her to see the wood for the trees. Focus on others for once. Her mum was always saying how her time at Oxford was so self-centred. It will only be for an hour and she can drive on to Swanage from there.

  ‘OK,’ she says. ‘I was just heading out in Mum’s car. I’ll be there as quick as I can.’

  ‘You’re a star, girl,’ Gladys says. ‘Park in the yard round the back.’

  Twenty minutes later, Bella is ladling out portions of curried coconut chickpea soup to a string of newly arrived migrants from Belarus, Somalia and Eritrea. It’s good to be back here again. She likes the work and is proud of her mum, how she’s set up a much-needed local facility. At one point, she offers to hold a baby while the mother, from Ethiopia, talks to one of the professional advisers who have volunteered their services for the afternoon.

  ‘You’re a natural,’ Gladys says, watching as Bella hitches the baby onto her own hip and carries on serving the soup. ‘Don’t know what we done without you – this place is bursting at the seams.’

  Gladys looks down the long queue. Bella follows her gaze, smiling at the array of people of every colour and creed, the way Gladys relishes the ‘r’ in ‘bursting’. They’ll all get help today with immigration paperwork as well as their housing applications. Some of the advisers are waiting at Formica tables spread throughout the hall, others are mingling.

  ‘Good to see you looking so well too,’ Gladys adds, more quietly now. ‘After all you’ve been through. I remember when you were this high’ – she puts a hand out at knee level – ‘and holding on to your mum’s pretty skirts.’

  Before Bella can ask Gladys what she means by ‘all you’ve been through’ – her dad’s death? – she spots a young policeman entering the door at the far end, making his way politely but purposefully through the queue. Bella swallows hard. Gladys has spotted him too – and Bella’s reaction. She doesn’t miss much.

  ‘Maybe you need to go get us some more soup,’ Gladys says, glancing again at the officer and then at Bella.

  ‘You think so?’ Bella asks, peering into the big stainless steel pot in front of her. It’s still half full.

  ‘I think so,’ Gladys says, giving Bella a wink. ‘I’ll handle things out here. Give me the baby.’

  ‘Thanks,’ Bella says, passing the baby over. The police officer is close now, making his apologies as he steers a course through the melee of people.

  ‘And if anyone asks,’ Gladys says, ‘you’re not here, right?’

  ‘Never have been,’ Bella says. ‘Thanks.’

  ‘Your secret’s safe with me,’ Gladys says. ‘But you tell me everything later. You promise?’

  ‘Promise.’

  Bella turns to take the pot back to the kitchen, her heart racing. She’s sure the policeman has come to ask about her. Unless he’s here to break some bad news about her mum.

  An old man she’s met before, from Ethiopia, is wiping down the surfaces in the kitchen as she places the pan beside the stove. The man only speaks Amharic. She puts her finger to her lips, smiles at him and slips outside into the back yard, closing the door behind her. A moment later, she hears Gladys’s voice in the kitchen.

  ‘I’m in charge today and I know we don’t have no Bella working round here,’ she’s saying, her voice loud and confident. ‘I’ve never even heard of a girl called Bella. I wish I had, mind – we could do with a pair of extra hands right now.’

  Bella stands and listens outside the door. Thank you, Gladys.

  ‘I just need to check,’ a man’s voice says. The officer’s, presumably.

  ‘What is this, some kind of a fed raid?’ Gladys asks, only half joking.

  ‘Nothing like that,’ the officer says. ‘Nothing to raid, is there?’ His to
ne has turned hostile. ‘If she does show up, give me a call on this number.’

  ‘Is she in trouble?’ Gladys asks.

  ‘I’m not sure why you’d care,’ the policeman says. ‘If you don’t know anyone called Bella.’

  Bella closes her eyes. Has Gladys blown it? She should go now, get in the car and drive to Swanage.

  ‘Ignore me, I’m just the nosy type,’ Gladys says, trying to recover the situation. ‘Want the curried soup on your way out? You could do with some meat on them skinny bones.’

  ‘On a diet,’ he says. ‘Smells good though. What’s through there?’

  ‘Nothing much.’

  Bella can hardly breathe. Keep going, Gladys. Do something – anything – to distract him.

  ‘It’s where we put the trash out,’ Gladys continues. Bella can hear the sudden tension in her voice. ‘You don’t want to go out there – it’s well renk on a hot day like this.’

  ‘I’ll decide where I look – if that’s OK with you.’

  57

  Silas

  Silas stands outside the entrance to the lower ground floor of the Great Western, around the corner from A & E, with Strover and four uniforms. The only time he’s been down here before was to have lunch with Mel at Bookends, the staff canteen in the training academy. She was tired in those days, angry with him and her job, Covid-19 and the government.

  ‘I’ll go first,’ Silas says, swiping the entry card that the estate manager gave him earlier. The manager stands back as Silas walks in, followed by Strover and the four officers, leaving a security guard to keep watch.

  ‘You take two officers and check the restaurant, I’ll do the kitchens,’ Silas says.

  It doesn’t take them long to establish that the fake doctor is not hiding in any of the obvious places. What bothers Silas is why he didn’t leave the site when his lift failed to turn up. Maybe he felt too exposed – there are cameras everywhere in the sprawling car park and exit road that winds down through it. Is his plan to lie low until someone can collect him?