‘Where are my kids? Where’s Nick?’ I ask. My voice sounds rusty.

‘Zoe and Jake are fine, Sally,’ says the woman. ‘They’re at Nick’s mum’s, and Nick’s at the shops. He’ll be back in a minute. Do you feel able to talk to us? Would you like a glass of water first?’

It comes from nowhere: a wave of panic that forces me upright. ‘Who is an innocent man?’ I gasp.

‘What? Calm down, Sally.’

‘You were talking about him before. Who isn’t with his family, or at work or home? Tell me!’

The police officers exchange a look. Then the woman says, ‘Mark Bretherick.’

‘He’s killed him! Or he will! He’s got him, I know he has…’

Simon has gone before I can explain. I hear him thudding down the stairs, swearing.

Sergeant Whatever looks at me, then at the door, then back at me. She wants to go with him. ‘Why would Jonathan Hey want to kill Mark Bretherick?’ she asks.

‘Jonathan Hey? Who’s he?’

She stands up and shouts the name Sam.

21

8/11/07

Charlie gripped the bottom of her seat as Simon overtook a Ford Focus and a Land Rover by swerving to their left and speeding ahead of them in the narrow gap between their sides and the kerb, to a chorus of angry beeps. Charlie could imagine what the drivers of the other cars were saying to their passengers: ‘Probably being chased by cops.’

‘I don’t get it,’ she said. ‘Hey’s in custody-ask him.’

‘And if he won’t tell me, or denies it? I’d have wasted time I can’t spare, not if I want to have a chance of finding Mark Bretherick alive. Hey locked Sally Thorning in a room and left her to die. What if he’s done the same to Bretherick?’

‘Why are you and Sally Thorning so sure Hey would want to harm Bretherick?’

‘I believe her. She’s spent time with him. She knows his mind better than I do.’

‘But… he killed them all, right? Geraldine and Lucy, and Encarna and Amy?’

‘Yeah. All of them,’ said Simon.

‘Why? Slow down!’ He had scraped the side of a van, was driving at twice the speed limit.

‘I don’t know.’

‘What?’

‘You heard.’

‘If you don’t know why, Simon, then you don’t know he did it. Not for sure.’

‘He had Bretherick’s suit in his wardrobe and a bloodstained shirt and pair of trousers in his bathroom-the clothes he was wearing when he cut Geraldine’s wrists. Oh, and he’s confessed.’

He was toying with her. Charlie refused to rise to it. She flinched as a red Mercedes had to swerve to avoid them.

‘To all four murders. He just won’t tell us why.’

‘How did you know it was Hey? Before Sellers saw the suit, before you had evidence?’

‘Something Sam said started me thinking. At Corn Mill House, when we found Encarna and Amy Oliva. He said something that stuck in my mind: “Family annihilation mark two.” It’s a funny expression, isn’t it? Not one I’d ever use myself. I’d have said number two, not mark two. For some reason it kept going round and round in my head.’

His speed was down to fifty-five. Talking was good for him. ‘I had that the first time I heard that mares-eat-oats-and-does-eat-oats rhyme,’ Charlie told him.

‘And little lambs eat ivy.’

‘Couldn’t get it out of my head for months, years, after I first heard it. Drove me mad!’

‘Another thing I couldn’t get out of my head-Geraldine’s diary, ’ said Simon. ‘From the start I was sure there was something wrong about it. I knew Geraldine hadn’t written it.’

‘Hey wrote it?’ Charlie guessed.

‘No, that’s what was wrong. I only realised much later, but deep down, subconsciously, I didn’t think Geraldine’s killer had written the diary either. It didn’t sound… made up. When I thought about it, I didn’t see how it could have been a fake. It was so detailed, so convincing. The voice was… A whole person, a whole life and world radiated from those printed-out pages whenever I looked at them. It sounds daft, but I felt a… a presence behind the writing, so much that was unsaid, so much more than the words in front of me. Could the killer really have created that illusion? Plus, we found out that the diary file was opened long before Geraldine and Lucy died.’

His speed was down to fifty.

‘So, whose diary was it?’ Charlie asked.

‘Encarna Oliva’s.’ Simon frowned as he saw the tailback in front of them. The centre of Spilling on a Saturday afternoon: always the same.

‘Which Hey kept after he’d killed her.’ Charlie worked it out as she spoke. ‘And after he’d killed Geraldine, he typed up Encarna’s diary on to Geraldine’s laptop… but you said the file was opened before Geraldine died?’

‘It was.’

‘I don’t get it.’ Charlie fumbled in her bag for her cigarettes and lighter. ‘Did Geraldine write the suicide note?’

‘Yep.’ Simon tapped the steering wheel impatiently. ‘Freely and willingly. It wasn’t a suicide note, that’s all.’

‘Then what was it? And what’s any of this got to do with Sam saying “family annihilation mark two”? Simon!’ Charlie clicked her fingers in front of his face.

‘Remember William Markes? “A man called William Markes is very probably going to ruin my life”?’

She nodded.

‘We couldn’t find any William Markes in Geraldine Bretherick’s life-’

‘Because the diary wasn’t Geraldine’s,’ said Charlie eagerly. ‘William Markes was someone Encarna Oliva knew.’ Was she catching up at last?

‘No. There is no William Markes.’

‘What?’

‘Find and replace. “Family annihilation mark two”-“mark” is a word as well as a name: full marks, mark that essay, a marked man. When we found Encarna and Amy’s bodies, Sam said he hoped Cook would find clear marks on the bones, to show how they’d died.’

‘Will it help if I beg?’ Charlie lit a cigarette. The traffic had begun to edge forward.

‘You’ve got Encarna Oliva’s diary on Geraldine Bretherick’s computer. You want people to believe it’s Geraldine’s. It’s full of gripes and complaints, exactly the sort of thing, you imagine, that would make Geraldine’s suicide more plausible. But the complaints aren’t about Mark and Lucy Bretherick, are they?’

‘No. Encarna would have complained… about Jonathan and Amy. Oh, my God!’ This time Charlie knew she understood.

‘The names had to change, if we were going to believe it was Geraldine’s diary. Quickest way? Find and replace all. Any idiot can do it in a keystroke.’

‘So all the Jonathans became Marks. Amy became Lucy.’

Simon nodded, playing bumper cars with the Audi in front of him. ‘Come on!’ he muttered through gritted teeth.

‘But… So William Markes…?’

‘Encarna Oliva called her husband Jon. And the “find and replace” manoeuvre did a bit more than Hey wanted it to. It changed Jon to Mark wherever necessary, yes, but Hey forgot that the letters j-o-n, like m-a-r-k, might crop up in other contexts too.’

Charlie chewed the skin around her thumbnail. ‘Which would make William Markes… William Jones?’

‘Right,’ said Simon. ‘The husband of Michelle Jones, who used to be Michelle Greenwood-Amy Oliva’s nanny. When Michelle told Encarna she had a boyfriend, Encarna was terrified he’d want to marry her; she was right, as it turns out. She was scared Michelle would have a family of her own, a life of her own. That’s what she meant when she said that a man called William Jones-a man she hadn’t yet met, but had heard about from Michelle-was probably going to ruin her life.’

‘Simon, you are a marvel of the modern world.’ Charlie inhaled deeply. This would be the best cigarette she had ever smoked, she could tell immediately. ‘But hang on… So you’d worked out that someone had done find and replace, but how did you get from that to knowing it was Jonathan Hey? How did you know Mark had replaced Jon, rather than, say, Paul or Fred?’

‘I got it wrong at first,’ Simon muttered, embarrassed. ‘When Sellers told me Amy Oliva’s father’s name was Angel. I assumed William Markes was William Angeles; thank God I didn’t go straight to the Snowman with it. Maybe on some level I knew it didn’t sound right. Because it wasn’t. Hey sent us on a wild-goose chase, pretending to be the man who’d bought the Olivas’ house, calling himself Harry Martineau. He invented a completely made-up father for Amy: Angel Oliva, a heart surgeon at Culver Valley General.’