There were three flights of stairs to the balcony and Shaw reached the top well before Valentine.
‘Alone?’ asked Shaw.
Bea turned her face, the ship’s fine figurehead, away from the sea to look at him. Below they heard Valentine’s mobile ring, followed by a whispered conversation.
‘Always,’ she said. ‘It’s not a problem.’ She touched a finger to her face, smoothing the single patch of makeup she wore.
She was standing, leaning easily on the low wall, a glass of white wine on the ledge. Shaw guessed it was a favourite spot; an escape from the people she had to let into her home.
‘We don’t have time,’ said Shaw. ‘John Joe’s life is in danger — it may even be too late. But you know that. You tried to kill him before, at the Shipwrights’ Hall lunch.’
She was prepared for that. Sipping the white wine, she used one hand to fasten the top button at her chin, then tighten a cashmere scarf.
‘It’s a cliche — but I really do have no idea what you’re talking about, Inspector.’
‘Toxic synergy,’ said Shaw. She was a very still person, but even Shaw sensed an instant immobility, as if those two words had turned her to stone.
Valentine arrived, out of breath, a thin veneer of sweat on his narrow forehead and showing through the thinning hair. He still held the mobile in his hand. ‘No sign of John Joe,’ he said. ‘Lizzie’s frightened now. Jacky Lau says she thinks that if he’s gone anywhere in the boat it would be here.’
Bea Garrison had spent her life maintaining an impenetrable exterior, but Shaw could see she was struggling now, her eyes drawn back out to sea, to the lights in the channel and beyond, to the darkness of the marshes. Shaw scanned the quayside, the mid-channel moorings, but there was no sign of John Joe’s clinker-built sailing boat.
‘We don’t have time for this, Mrs Garrison. If John Joe Murray dies, you will be responsible. Where is he?’
She set her hard face to the sea. Out along the quayside a council Scarab swirled up the rubbish. Towards the dunes a bonfire flickered. Shaw was struck again by how imperious Bea Garrison was, how she’d carved a life for herself, a woman alone, deserted by men: first a husband she didn’t love who drank himself to death, and then — as far as she’d known for the last three decades — by the son she did love. But she’d survived, prospered in a way, and then, provided with the names of the men who’d killed that son, she’d organized a clinical and lethal revenge.
‘We know you told Alby that night — at the Clockcase — about what Kath had seen,’ said Shaw. ‘Did he mention the Shipwrights’ Hall lunch then? It’s an annual affair. Every year he’d worked at the cannery he’d have seen the order go through. So he knew the Flask would have a table and that all three of your targets would be there. And I think it was you who thought of revenge — an almost instant retaliation. You asked Kath Robinson not to tell us what happened, didn’t you? What did you say? That after all those years it was unlikely — nearly impossible — that we’d be able to make a case against them? But she didn’t listen. That’s the neighbourhood vice around the Flask — gossip.
‘But that didn’t mean the three of them couldn’t be punished. That they couldn’t suffer. So you told Alby to lace the cans. You knew they’d have the soup, of course — they eat at the Flask every week, so you knew they were all keen on seafood. And local fare. It’s a guess, but I think you didn’t tell him how it would work, or that they’d die. He’d have to trust you — trust that only they would really suffer. And anyway, he knew that the dose he was giving them wasn’t lethal — it doesn’t even work on the rats every time.’
She turned her back on the sea and looked up at the tower of Morston House, and Shaw wondered if she was saying goodbye, trying to imprint a memory that she could take with her.
‘Toxic synergy,’ he said. ‘Occupational hazard if you’re a chemist. Which you were, of course. You, Mrs Garrison, not Latrell. That was a lie — and a desperate one. So I think you suggested using the rat poison to make them suffer, then went out to the poison bin to check on its chemical composition. And perhaps that’s when you realized you could do it. Kill just those three and nobody else.’
Across the water the sound of a second champagne bottle opening bounded to them.
‘The real question,’ said Shaw, ‘is what did you tell Ian.’
Shaw smiled and took one of the wooden chairs. Out in the channel a water rat surfaced and swam towards the open sea, leaving a perfect V-shaped wake.
‘Because that was part two of the plan — the part Alby didn’t know about. Before they got to Alby’s rat poison at the Shipwrights’ Hall you needed to make sure they each had a dose of mercury in their bloodstream. Just a bit — nothing fatal. Again, a non-lethal dose. And they got that, I’d guess, at lunch on Tuesday at the Flask. A lunch Ian cooked. Angry, bitter, Ian. Three daily specials: grilled salmon with bubble and squeak and winter vegetables. And here I’m guessing again. I don’t think Ian knew the two halves of the plan, did he? You asked him to trust you, just like you’d asked Alby.
‘It’s the ultimate toxic synergy: aluminium and mercury. Individually slow acting and non-lethal, but put them together and the result is guaranteed. It’s a textbook study: give a hundred rats a dose of aluminium and on average one will die; give a hundred rats a dose of mercury and on average one will die; give a hundred rats a dose of both and they’ll all die. Every time.’
Valentine lit a Silk Cut, absorbed by Shaw’s account.
Bea turned towards them, a hand finding the wooden shelf on the low balcony wall without looking, an action of familiarity which reminded Shaw of Lizzie Murray reaching for the fruit-machine switch behind the bar of the Flask.
An ice bucket stood in the corner, and she walked to it now and refilled the glass of wine.
‘I like it cold,’ she said. ‘Icy.’
She stared Shaw in his blind eye.
‘I’m not sure you have a single item of evidence to support this fanciful scenario,’ she said. But her age betrayed her: the wine glass rocking as the tendons in her arm failed to smoothly elevate it to her lips.
‘You have three problems,’ said Shaw. ‘Alby is happy to confess to his side of the plan — although I will concede that he’ll never implicate you directly, as he is actually pretty keen to spend the rest of his life in a secure cell at Lincoln. I just wonder how coherent his testimony would be under cross-examination. Especially as his sabotage was carried out before the discovery of Pat Garrison’s bones was made public, and he admits to seeing you only hours before he laced the cans. Second, I think Freddie Fletcher fell ill during his lunch at the Flask. I think the mercury was in the salmon — he started feeling nauseous before he’d finished, so he used the foil from his sweetcorn cob to wrap up the fish. It’s a generation thing: waste not, want not. He wouldn’t have suspected the meal he was currently eating. Probably blamed it on a dodgy curry the night before. It’s in his fridge, the salmon. Well, it was in his fridge — it’s in our forensic lab now. Where we will also be spending some of our budget on a more thorough examination of the stomach contents of Fletcher and Venn. We’ll find the mercury, although I suspect the amounts will be truly microscopic. Because that’s the dreadful beauty of toxic synergy — the traces of the two poisons can be almost undetectable, especially if you’re not looking for them.
‘And third, and most importantly, Fletcher, Venn and Murray didn’t kill your son.’
She shook her head and tried a laugh, but it died in her throat.
‘How do we know this? Well, initially we ignored several pieces of evidence which didn’t fit the scenario painted by Kath Robinson — a story, by the way, which I’m sure was genuine in outline.’