‘Listen to me and listen carefully, Detective Constable.’ Proust jabbed Simon’s neck with his index finger. That was a first. Verbal abuse Simon was used to; the prodding was new. ‘Peter Parker is my mechanic and Billington’s my uncle. Decent law-abiding citizens both. I’m sure you don’t need me to tell you why we’re not going to start snouting around in their private affairs on the off-chance that Mrs Bretherick might have been mistaken when she typed the name William Markes. Do I make myself clear?’

‘Sir.’

‘Splendid.’

‘What about the note from Spilling Post Office?’ Simon challenged the inspector’s retreating back. ‘The note that someone passed on to you. Mark Bretherick might not be Mark Bretherick. Are we going to investigate that?’

‘Gone are the days, Waterhouse, when the police were able to dismiss attention-starved cranks as the fruit-bats that they inevitably turn out to be. Your sergeant will be giving this new information his full attention, won’t you, Sergeant?’

A few seconds before Kombothekra found his voice. ‘I’ve already made a start. So far it looks as if Bretherick’s who he says he is.’

‘Waterhouse probably believes his real name is William Markes. ’ Proust snarled. ‘Eh, Waterhouse?’

‘No, sir.’ Simon was thinking about the cards, the two ten-year-wedding-anniversary cards on the mantelpiece at Corn Mill House. He could picture them clearly. Both were large, A3 size. One had curved edges, swirly silver writing-‘For my darling husband, on our anniversary’-above a picture of a yellow flower. The other was pink and padded, with the number 10 and a bouquet of roses on the front. The roses were tied with a pink bow. Simon had memorised what was written inside the cards. Why? So that he could discuss it with Sellers and Gibbs, see what they thought? Proust? They’d laugh him all the way out of the building, any of them would. Even well-meaning Sam Kombothekra.

No, he didn’t think Mark Bretherick was William Markes, not necessarily. But those cards…

‘If it were up to me, we’d have someone watching Spilling Post Office,’ he said. ‘Whoever wrote that note’s got more to say. He or she might write another longer letter in the next few days. If we can get hold of that person, we’ll have a lead and possibly a suspect.’

‘I’d like to put you on a lead, Waterhouse,’ was Proust’s response.

‘Simon, we’ve got a suicide note’-Kombothekra pointed to the whiteboard-‘and a diary that makes it clear Geraldine Bretherick was depressed.’

‘A diary that was found on a computer.’ Simon sounded like a truculent child even to himself. ‘No hard copy, no notebook version. Who types their diary straight on to a computer? And why are there only nine entries, all from last year? Not even nine recent, consecutive days-nine random days from April and May 2006. Why? Can anyone tell me?’

‘Waterhouse, you’re embarrassing yourself.’ Proust belched, then looked at Sam Kombothekra as if he expected to be chastised for his lack of etiquette.

‘I’ve got a copy of this article for each of you.’ Kombothekra picked up the bundle of paper that had been on the table next to him since the beginning of the briefing. It was as if Simon wasn’t there, had never spoken. Why had he bothered? ‘It’s Professor Harbard’s latest publication,’ said Kombothekra.

‘We already know what that ego-maniac thinks,’ Proust snapped. ‘That Geraldine Bretherick was responsible for both deaths. I stand by what I said at the time: he knows no more than we do. He knows less than we do. He wants this death to be a family annihilation-a thoroughly repugnant phrase which he probably invented-because then he gets to air his nonsense predictions on national television: within five years every mother in the country will be driving herself and her offspring off the nearest cliff or some such guff!’

‘He’s studied many murder-suicide cases similar to this one, sir,’ said Kombothekra, his tone as benign as if the Snowman had just offered him a toasted teacake. Kombothekra felt sorry for Professor Harbard; he’d as good as admitted it to Simon during one of their awkward, mainly silent drives to Corn Mill House. ‘It can’t be easy for the man, can it?’ he’d said. ‘He’s called in by the super, as an expert, then finds himself in the middle of us lot, being treated like an intruder and a cretin.’ Simon had wondered if Kombothekra was talking about himself, his own experience.

To Simon, Harbard had seemed as thick-skinned as a cactus. He was a bad listener. When other people spoke, he nodded impatiently, licking his lips every few seconds and murmuring, ‘Yes, yes, okay, yes,’ revving up for his next turn under the spotlight. The only time he’d listened attentively was when Superintendent Barrow had popped in to give the team a pep-talk, reminding them of Professor Harbard’s eminence in his field, how lucky they were that he’d offered his services.

‘I’ve underlined the paragraph that I think constitutes new information,’ said Kombothekra, putting a copy of the stapled article into Simon’s hands and taking the opportunity to bestow another smile upon him. ‘At any rate, I can’t remember Professor Harbard telling us this in person. In paragraph six he says that family annihilation is not a crime that can be attributed to social exclusion or poverty. Most commonly it occurs among the affluent upper-middle classes. Harbard argues that this is because of the need to keep up appearances, to present an image of perfect family life, happiness, success. In the higher socio-economic echelons, image matters more…’

‘Please don’t talk to me about echelons, Sergeant,’ said Proust.

‘… people want to be the envy of their friends, so they put on a front. And sometimes, when the more complicated and painful reality of life intrudes-’

‘That’s crap,’ Simon interrupted him. ‘So because the Brethericks were upper-middle class and had money, that means Geraldine’s a murderer and a suicide?’

Proust glared at Kombothekra, rolled up his copy of Professor Harbard’s article and launched it at the bin in the corner of the room. It missed.

‘What about the GHB?’ Simon wondered if he could make some headway as the lesser of two evils now that the Snowman was angry with Kombothekra. ‘Why did Geraldine Bretherick take it herself? Where did she get it?’

‘Internet,’ Gibbs suggested. ‘It’s not hard to get hold of. As for why, GHB’s fast replacing Rohypnol as the most popular date-rape drug in the country.’

‘Would a woman like Geraldine Bretherick, given everything we know about her, buy illegal drugs on the Internet?’ said Simon. ‘This is a woman who runs the Parents and Friends Committee at her daughter’s school, whose kitchen bookcase is full of books called Fish Dishes to Make Your Child’s Brain Grow and shit like that.’ Unwillingly, he looked at Kombothekra. ‘Have we heard back from HTCU yet about the computer?’ The high-tech crime unit was referred to as ‘Hitcoo’ by everyone in CID apart from Proust.

The sergeant shook his head. ‘I’ve been chasing and chasing. No one can tell me why it’s taking so long.’

‘I bet they’ll find no GHB was ordered from Geraldine Bretherick’s laptop. And I didn’t mean why GHB instead of Rohypnol, I meant why any drug? Okay, in Lucy’s case I can understand it-she wanted Lucy to pass out so that all she’d have to do was push her under the water. So that Lucy wouldn’t feel any pain. But why take it herself? Think of how much she had to do and do efficiently: kill her daughter, write a suicide note, turn on her computer and open that diary file, leave it on the screen so that we’d find it when we arrived, kill herself-wouldn’t she want a clear head?’

‘Slashing your wrists hurts,’ said Sellers. ‘Maybe she wanted to dull her own pain. There was more GHB in Lucy’s urine than in her mother’s, a lot more. It looks as if Geraldine only took a bit, to take the edge off her fear, probably-make everything a bit hazy around the edges. And that’s exactly what happens, that’s what a small dose of GHB does.’