Stepford had interviewed Oonagh O’Hara yesterday and she’d told him she hadn’t heard from Amy since last May. Clearly she was lying. Or rather she believed she was lying. In fact, she’d told the truth: she had been exchanging letters with Amy’s killer, not with Amy.

Gibbs raced through the messages. At the end of each of her letters, before signing off, Oonagh had written, ‘Hows your mum?’ or ‘Is your mum okay?’ In one she’d gone further and said, ‘How are things with you and you’re mum?’ Twice, after enquiring about Encarna Oliva, Oonagh had written ‘Hows Patrick? ’ and once, ‘Hows Partick?’

Had Encarna Oliva left her husband for another man? Had Patrick worked at the bank with her? Or maybe he’d been a friend or colleague of her husband’s, someone Angel Oliva had worked with at Culver Valley General Hospital. There were some women, Gibbs knew, who’d think nothing of shagging their husbands’ mates. Gibbs thought it was inevitable that one day Sellers would try to bed Debbie; he was training himself to dislike Sellers in advance, so that when it happened he’d be prepared.

Amy’s replies to Oonagh’s e-mails were chatty but bland, full of news about watching bullfights and flamenco dancers. Clichés of Spain. Lies. Despite her e-mail address, Amy Oliva never got to Spain. She never got further than the garden at Corn Mill House. Interestingly, she-her killer, Gibbs corrected himself-had not once answered Oonagh’s enquiries about Encarna and Patrick.

Why had Oonagh O’Hara lied about when she’d last been in touch with Amy? There was nothing secret or personal about any of these e-mails. ‘Something weird’s going on,’ Gibbs said aloud.

He was on his way out of the CID room when the phone rang. It was Barbara Fitzgerald, the head of St Swithun’s. ‘Hello, Christopher,’ she said warmly, once Gibbs had identified himself. ‘I’m just phoning to let you know I’ve e-mailed you a full list of everyone who went on the owl sanctuary trip last year. I did forget a few names, as it turns out.’

Gibbs thanked her.

‘Is there… any news?’

‘No.’ He didn’t want to be the one to tell her that another of her pupils had been murdered. Nor did he want to talk, knowing what he was withholding; guilt made him more brusque than usual and eventually Barbara Fitzgerald gave up.

Feeling unsettled, ashamed of his cowardice, Gibbs navigated his way back to Yahoo Mail. He entered his ID and password, and was waiting for his inbox to appear when he realised his mistake. Barbara Fitzgerald didn’t know his Yahoo address; she would have sent the list of names to his work e-mail, the address from which he’d e-mailed her earlier. Dick-brain. He was about to log out of his Yahoo account when he saw that he had a new message. From Amy Oliva. No amount of blinking made it disappear.

Gibbs double-clicked on the envelope icon. The message had been sent from a Hotmail address, but a different one: [email protected]. It was only three words long, three ordinary words that worried Gibbs more than an overt threat would have. He got up and left the room, not bothering to sign out of his account.

Meeting room one for a team briefing? What was wrong with the CID room? Charlie had always found it perfectly adequate. She broke into a run as she turned the corner. By the time she got there she was out of breath. She knocked and opened the door. Sam Kombothekra, Simon, Sellers and Professor Keith Harbard sat in silence on comfortable blue leather chairs that looked as if they belonged in the executive row of a multi-screen cinema. Harbard was eating a muffin, dropping crumbs on the carpet around his feet.

Inspector Proust stood in the corner of the room by the water cooler with a mobile phone pressed to his ear, talking too loudly about a DVD player that was ‘too complicated’. Had he phoned a shop on the other side of the world to complain?

‘What’s going on?’ Charlie asked.

‘We’re waiting for Gibbs,’ said Sam.

The Snowman interrupted his phone call to say, ‘Round him up, will you, Sergeant?’

Charlie realised he was addressing her. Bloody cheek. ‘I can’t stay, sir. I need one of you to come with me. I think I’ve got something that’s going to help you.’ She didn’t dare ask for Simon. Not in front of everyone.

‘Off you go, Waterhouse,’ said Proust. Charlie could have kissed him. ‘Don’t let it take too long, Sergeant.’

‘I feel like the kid whose mother turns up two hours early to collect him from the party,’ said Simon, following Charlie down the corridor.

She smiled at him over her shoulder. ‘Did your mother do that?’

No reply.

‘She did, didn’t she?’

‘What’s this about, anyway?’

‘By the time I’ve explained…’

They marched the rest of the way in silence. Charlie stopped outside interview room three and Simon walked into her. She grinned determinedly as he leaped back, alarmed by the unexpected physical contact.

She opened the door. A broad-shouldered woman with short spiky dyed hair and a pained expression on her face sat behind the table. She was wearing black tracksuit bottoms with pink stripes down the legs, pink lace-up pumps and a tight pale pink polo-necked jumper that clung to the rolls of flesh around her middle. ‘This is Pam Senior,’ Charlie told Simon. ‘Miss Senior, this is Detective Constable Simon Waterhouse. I’d like you to tell him what you’ve just told me.’

‘All of it?’

‘Yes, please.’

‘But… I can’t sit here all day, I’m self-employed. I’m a childminder. I thought you’d have told him already.’

When Charlie didn’t respond, Pam Senior sighed and started to talk. A woman she didn’t know had turned up on her doorstep last night, she said. Late: eleven o’clock. She’d introduced herself as Esther Taylor and said she was the best friend of a woman whose children Pam sometimes looked after-Sally Thorning. She’d demanded to know what Pam had done to Sally, and tried to force her way into Pam’s house.

‘She called me a liar, accused me of all sorts-pushing Sally under a bus, but I didn’t, I swear! Sally must have told her I did, though, and now she reckons Sally’s disappeared and I must know something about it. She was threatening to go to the police. ’ Pam’s nostrils flared. She sniffed several times. ‘So I thought I’d better come here first and tell you I’ve done nothing, absolutely nothing. What she’s saying’s slander, and that’s illegal, isn’t it?’

‘Under a bus?’ said Simon. ‘Are you sure that was what she said? Where do you think she got that from?’

‘Sally did have an accident with a bus, in Rawndesley a few days ago. I was there, I saw it. Well, I didn’t see it happen, but I saw a group of people all gathered round, so I went and looked, and it was Sally. I tried to help her, offered to take her to hospital to get checked out, but she wasn’t having any of it. She accused me of pushing her and shouted at me in front of everyone.’ Pam’s face reddened as she remembered the incident. ‘We’d had a bit of a row before, because of a mix-up over childcare arrangements, and I’ll admit I was furious with her, but… what sort of person does she think I am, that I’d do that?’

‘So you didn’t push her?’ said Charlie.

‘Of course not!’

‘And you didn’t see if anyone else pushed her?’

‘No. I told you. I’ve been upset about it all week. I was just starting to feel better-Sally left a message saying she was sorry, and I thought it was all over-and then this Esther Taylor woman turns up. She tried to barge into my house. Look.’ Pam held out her hand so that Simon could see it shaking. ‘I’m a wreck.’

‘Tell him the rest,’ said Charlie.

‘I managed to keep her out, slammed the door on her.’ Pam touched her throat. ‘She started yelling outside about Mark Bretherick, asking if he was the one who… who wanted Sally dead. I can hardly bear to say it, it’s so awful. I read the local paper every night, so I recognised the name. That was what freaked me out the most.’ She pulled a handkerchief out of the pocket of her tracksuit trousers; it had the initials PS embroidered on it. It had been ironed, Charlie noticed, and folded into a neat square.