Shape of Snakes

'No,' he agreed, 'but it was the last time ... and I'd told you it was going to be the last time over the phone that afternoon. I said I wanted to talk to you about ending the affair without destroying everyone in the process. And I was furious when you draped yourself all over me the minute I came through the door, saying you'd had a bath in my honor and were washing sheets so you'd be able to replace our dirty ones on the bed before Jock came home. You can't have forgotten that, Libby. You told me I was frightening you because I said I'd do you some damage if you didn't take your hands off me immediately.'

She gave a small laugh. 'Oh, well ... if that's how you want to play it ... it's no skin off my nose. What does it matter what I was doing, anyway?' She shifted her gaze back to me. 'We'll go with Sam's version. Does that make you happy?'

I nodded.

'Then you're a fool.'

'Maybe.' I crossed my arms and studied the point of my shoe, in no hurry to go on.

'Is that all there is?' she said indignantly. 'Did you make me come all this way just so you could feel better about your husband's cheating?'

'Not quite,' I said without rancor. 'There's a major question mark over the time of Sam's arrival. He says 7:45, you say 6:30.'

She frowned, as if trying to remember. 'Okay, split the difference,' she said helpfully. 'Make it 7. Neither of us can be that precise after twenty years.'

'Sam can,' I countered mildly. 'He's worked out his timing rather more accurately than you have ... and there's no way he could have reached you before a quarter to eight. If you calculate his walk from the office to the tube, the average time of the train journey, plus the walk from Richmond station to Graham Road, it's impossible for him to have done that trip in under an hour and a quarter. Which means 7:45 has to be the agreed time because he didn't leave work until 6:30.'

Her hands moved impatiently in her lap. 'How do you know that? Why should Sam's memory of the time he left his office be any better than mine of the time he arrived?'

'Because I'm not going by Sam's memory,' I told her. 'I was so suspicious of him after he and Jock made their statements that I checked with his office. I hoped I could get some proof that he was lying about the time he reached Graham Road because I knew the security guard clocked everyone out at the end of the day to make sure the building was empty before he locked up. I persuaded him to let me have a photocopy of the register for 14.11.78.' I nodded toward the rucksack at my feet. 'It's in there with 18:30 against Sam's name.'

Her eyes dropped immediately to the bag but she didn't say anything.

'So we're agreed that 7:45 was the time Sam arrived?' I repeated.

She made a dismissive gesture with her hand. 'I can't see what difference it makes. All we did was talk.'

'Yes, that's what you both say. Your version is that you talked for two and a half hours. His is that you talked for an hour.'

She shrugged. 'I didn't keep track.'

'But you disagree over how the conversation went. Sam says he gave you an ultimatum-either the affair had to end or he'd come clean with me that night. You say it was you who delivered the ultimatum.'

She cast a malicious glance in Sam's direction. 'He can't say anything else,' she said, 'not if he wants you to believe I draped myself all over him when he came through the door.'

I smiled slightly. 'But that's the whole point, Libby. After the show you put on when he arrived, Sam expected you to be difficult ... but you weren't. You said you'd leave him alone ... no more hanging around outside his office ... no more demands on his time ... and the only quid pro quo was that he keep his mouth shut so that Jock wouldn't have an excuse to divorce you.'

''Which suggests it was me who delivered the ultimatum, doesn't it?'

'If that were true, why was Sam so keen to accept it?'

Her eyes narrowed warily as she tried to see the point I was making. 'What makes you think he was?'

I shrugged. 'Because he couldn't sign up to your fabricated alibi quick enough. He was even happy to rope Jock into the lie if it meant he could distance himself from you. Not that your husband minded,' I said with an ironic glance in Jock's direction, 'because he didn't want his Tuesday evenings with Sharon made public. But why would Sam go along with it unless he had something to gain? There were any number of reasons he could have given for being in your house that night-none of which were remotely suspicious. Looking for Jock, being one.'

'Why ask me?' she demanded. 'Sam's the one who lied. All I did was tell the truth, which was that I'd been at home all evening, waiting for my husband. And I didn't have to pretend I was alone either because the police made that assumption themselves. It's not my responsibility if Sam decided to sign a statement saying he was at your place when he wasn't.'

'Except he says you didn't give him any choice. According to him, you phoned him at his office the next morning to say the police were asking about people's movements the previous night because they were looking for anyone who'd seen Annie. You then told him you'd dug him out of a hole by saying he and Jock had been at our house from 7:45 and it was down to him to persuade Jock to support the story. You said I'd never suspect he'd been with you if it was your husband who gave him an alibi. And you were right, I didn't.'

'This is Sam's version, presumably?' she murmured sarcastically.

'Yes.'

She glanced at my rucksack again. 'And there's no statement from an earwigging telephone operator to back it up?'

'No.'

'Then you can believe what you like, and the police can believe what they like.' she said indifferently. 'Sam's always going to put his own gloss on it-he wouldn't be human if he didn't-but he's the one who lied and I'm the one who told the truth. And I'm