‘Criminal tricks are different from magic tricks. Do you know what the difference is?’ He waited for Utsumi to shake her head before continuing: ‘They both contain a secret, but the fate of that secret is not the same. With a magic trick, as soon as the show is over, the opportunity for the audience to perceive the secret is gone. However, with a criminal trick, investigators can pore over every detail of the crime scene until they’re satisfied. If a trick was used, some trace always remains. The most difficult thing when committing a crime is to perfectly cover one’s tracks, wouldn’t you agree?’
‘What if the tracks were covered?’
‘Going on what you’ve told me, I would have to say that the possibility is extremely low. What was the other girl’s name again, the lover?’
‘Hiromi Wakayama.’
‘She’s testified that she drank coffee with the victim, correct? Not only that, but she made the coffee. If the coffee had already been poisoned, why didn’t it kill both of them? That’s the biggest mystery here. I liked your conjecture about the magic powder that makes coffee taste better – in other words, setting the victim up to poison himself. That sort of thing makes for an excellent murder mystery, but it’s not a method a real criminal would choose.’
‘How do you know?’
‘Imagine that you were the guilty party. What if you gave him the poison and he used it somewhere outside the house? What if he went over to a friend’s place and told them about this great powder his wife had given him, and they drank it together?’
Utsumi bit her lip. He had a point. Worse, she realized she had been clinging to the theory as a real possibility.
‘If the wife was indeed the murderer, there would be at least three hurdles for her to clear,’ Yukawa said, holding up three fingers. ‘One, no one must notice or have reason to believe that the poison had been placed before it was ingested. Otherwise, there’d be no point in constructing an alibi. Two, she would have to be sure that it was Mr Mashiba who took the poison. She might not mind getting the lover, too, as collateral damage, but she would have to be sure to also get her mark. Third, the whole plan would have to be something easily prepared in a short amount of time. There was a dinner party at their house the night before she left for Hokkaido, correct? If she’d placed the poison before then, there’d be too much danger of someone else taking it. I think she would’ve placed it afterwards.’ He raised his hands. ‘And I can’t think of how anyone would be able to do that. Sorry.’
‘Are those hurdles all that difficult?’
‘They seem pretty difficult to me. The first, in particular. I think it makes far more sense to assume that the guilty party is not the wife.’
Utsumi sighed. If the physicist, the so-called Detective Galileo himself, was telling her it was impossible, then maybe it was.
Her mobile rang. She picked up, watching Yukawa refill his coffee mug out of the corner of her eye.
‘Where are you?’ It was Kusanagi. There was a roughness in his voice.
‘Asking questions at a pharmacy. I was told to investigate possible routes for obtaining arsenous acid. Is something wrong?’
‘Forensics came through. They found poison somewhere other than the coffee.’
Utsumi gripped her phone tighter. ‘Where?’
‘The hot water kettle on the stove.’
‘The kettle? Really?’
‘Just a trace amount, but it was definitely there. I’m going to be taking Hiromi Wakayama in for questioning.’
‘Her? Why?’
‘Her prints were on the kettle.’
‘Of course they were. She made coffee on Sunday morning.’
‘Which means she had the opportunity to put poison in it.’
‘Were hers the only fingerprints they found?’
‘No, the victim’s were on there, too.’
‘What about the wife’s fingerprints?’
She heard a deep sigh on the other side of the line. ‘Of course they were, she lives there. But she wasn’t the last one who touched it. They can tell by the way that the fingerprints overlap. Also, there was no indication that anyone had touched it wearing gloves.’
‘I understand that glove marks don’t always remain.’
‘I know that. But look at the circumstantial evidence as a whole: no one but Ms Wakayama could have put the poison in. We’re going to be questioning her down at Division, and I want you there. Now.’
He hung up before she could answer.
‘Sounds like a development,’ Yukawa said, standing while he drank.
Utsumi related to him what Kusanagi had told her. He listened, lips on his mug, not even nodding while she spoke.
‘The kettle? Really?’
‘That’s what I said. Maybe I have been thinking too much. On Sunday morning, Hiromi Wakayama used the same kettle to put on coffee, and drank it with the victim. That has to mean that there was no poison in the kettle at that point. Ayane Mashiba couldn’t have done it.’
‘Why not go a little further and say that there was no reason for the wife to put poison in the kettle? There’s no trick to that at all.’
Utsumi cocked her head, unsure of what he was saying.
‘Just now, you admitted that it couldn’t have been the wife,’ he explained. ‘But you can only say that because there was someone who used the kettle – without dying – after she left, but before the crime was committed. What if no one else had used the kettle? Then the police would have gone straight to the wife as the most obvious suspect. Surely she would have known that, so why would she go out of her way to make an alibi at all? It wouldn’t have held up.’
‘Oh. That’s true,’ Utsumi said, her head drooping, her arms folded across her chest. ‘Either way, this removes Ayane Mashiba from the list of suspects, doesn’t it?’
Yukawa didn’t answer. He was staring at her.
After a moment, he said: ‘So, where does this leave you? If the wife wasn’t the murderer, are you going to join Kusanagi in suspecting the lover?’
She shook her head. ‘No. I don’t think so.’
‘Such confidence. Mind telling me why? Please don’t tell me you don’t think she could kill the man she loved.’ Yukawa sat in his chair and crossed his legs.
Utsumi panicked – she had been about to say that very thing. Other than that, she couldn’t think of any reason why it hadn’t been Hiromi Wakayama.
But the more she stood there, looking at Yukawa, the more she started to believe that maybe he didn’t think it was Hiromi Wakayama, either, and that he had some reason why he thought she was innocent. The only details he knew about the case were what she’d just told him. So somewhere in there had to be a hint that it wasn’t the young apprentice who put the poison in the kettle.
With a little gasp, she looked up.
‘Something on your mind?’
‘She would’ve washed the kettle!’
‘Oh?’
‘If she put the poison in the kettle, she would have washed it before the police came. She was the one who discovered the body, after all. She had plenty of time!’
Yukawa nodded, a satisfied look on his face.
‘Precisely. We might add that, were she the murderer, she wouldn’t have just washed the kettle, but also disposed of the old coffee grounds and the paper filter. Then, if I were she, I would have placed a little baggie of poison next to the body. To make it look like a suicide.’
Utsumi gave a little bow with her head. ‘I’m glad I came. Thank you.’
She turned and started walking towards the door when Yukawa called out, ‘Oh, Detective.’ She stopped.
‘I’m guessing I won’t be able to view the crime scene, but if you had some photos …’
‘Photos of what?’