‘To put it simply, none of your business.’ He smiled thinly. ‘Why did you go on with the case after Kodaka was killed? You weren’t working for him any more. He wasn’t paying you. You owed him nothing. And you must have known you were taking a big risk by continuing. Why didn’t you just give up?’

‘Have you read the kage-boshi file?’

‘I cast an eye over it while you were in the shower. None of the contents came as a surprise to me. But for a private detective to have amassed so much damaging information about Nishizaki? That was a surprise. I fear Kodaka may have been skating on thin ice for a long time. His intervention in the affairs of Shitaro Masafumi’s family wasn’t something Nishizaki was ever likely to tolerate.’

‘Did Nishizaki have Masafumi killed?’

‘I suspect so, though I can’t be absolutely sure. It could genuinely have been suicide. But back to you, Wada-san. Why didn’t you give up when it was obviously the best and safest course of action?’

‘Because of what’s in the kage-boshi file.’

‘Nishizaki isn’t the only villain operating in the Japanese business world. He isn’t even the biggest. I can’t believe you were shocked by what you read. It didn’t affect you personally in any way.’

‘But it did.’

‘How?’

‘Yozo Sasada.’

‘Sasada? What was he to you?’

‘My husband’s killer. That is what he was to me.’

‘Ah.’ Driscoll slid back on the sofa and looked at Wada with greater attention than before. ‘Your husband died in the sarin subway attack. I didn’t know that. I should have known, of course. Sarin.’ He sighed. ‘Thus the whirligig of time brings in his revenges.’

‘Sasada worked for your company.’

‘But he was always Nishizaki’s man. He’d been given a secret mission: to penetrate Aum Shinrikyo and use their people to carry out elimination operations against Nishizaki’s enemies in exchange for know-how and funding. The plan had to be abandoned after Nishizaki realized the organization was becoming dangerously unstable. By then, Sasada had succumbed to their crazed philosophy.’

‘Did Aum Shinrikyo use sarin of their own accord? Or did Sasada suggest it to them?’

‘You’re going to blame me, aren’t you? You’re going to say my past, which I didn’t – couldn’t – hide from Nishizaki, was the germ of the idea – the cause of the whole mad murderous mess.’

‘Was it?’

‘There’s no yes or no answer. Not one I’ve ever found, anyway.’

‘Have you looked?’

‘I could tell you I have and be lying. I could claim I’ve lain awake at night wondering what measure of responsibility I bear and you wouldn’t know any better. What difference does it make what I say? The dead will stay dead.’

‘What will you do with the kage-boshi file?’