‘If the murder weapon were something direct, like a knife or a gun, I would agree. But this is a poisoning, and it’s possible to commit the act before the actual murder happens.’

  ‘So you want me to figure out how she did it?’

  Utsumi waited in silence.

  A knowing smile spread on the physicist’s lips. ‘Perhaps you’ve got the wrong impression somewhere along the line, but physics is not magic.’

  ‘But you’ve solved plenty of cases before now involving tricks that seemed like magic.’

  ‘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?’

  ‘The kitchen where the coffee was poisoned, for starters. And a picture of the cutlery and kettle in evidence.’

  Utsumi’s eyes widened. ‘You’re going to help?’

  Yukawa frowned and gave his head a scratch. ‘I might think about it a bit, in my spare time. I’m curious to know how someone in Hokkaido was able to poison someone in Tokyo, a thousand kilometres away.’

  Utsumi grinned despite herself. Reaching into her shoulder bag, she produced a folder. ‘Here.’

  ‘What’s this?’

  ‘The photos you asked for. I took these this morning.’

  Yukawa opened the file and pulled back a little.

  ‘If we figure out how she did it,’ he said with a grin, ‘we can serve Detective Kusanagi a lethal dose of humble pie.’

  TEN

  When Kusanagi called Hiromi Wakayama, she was in Ayane Mashiba’s patchwork classroom. He jumped in the car with Kishitani behind the wheel and they headed for the school. The place was a white apartment building with tiled walls, nestled in amidst a row of trendy stores. There was no lock on the building’s main door, unusual for that area. They took the elevator up to the third floor, where a sign on room 305 read ‘Anne’s House’.

  Kusanagi pressed the doorbell and, almost immediately, the door opened. Hiromi looked out, a worried expression on her face.

  ‘Sorry to barge in like this,’ Kusanagi said, stepping inside. He squared his shoulders. ‘Actually …’ The words died on his lips. Ayane Mashiba was behind Hiromi, seated in the centre of the room.

  ‘Did you find anything out?’ Ayane got up and came towards the detectives.

  ‘I’m sorry, Mrs Mashiba, I didn’t know you were here, too.’

  ‘Hiromi was helping me make some decisions about what to do now. Did you need her for something? I’m sure she’s told you everything she knows.’

  Her voice was low and calm, but it held a definite tone of irritation directed towards Kusanagi. Her eyes fell on him, and the sorrow in them made him shrink back.

  ‘Actually, there’s been a slight development in the case,’ Kusanagi said, turning towards Hiromi. ‘I’d like you to come with us back to the station.’

  Hiromi’s eyes opened wide and she blinked several times.

  ‘What’s all this about?’ Ayane asked. ‘Why does she have to go with you?’

  ‘I’m afraid I’m not at liberty to talk about that right now. Ms Wakayama, if you wouldn’t mind? Don’t worry, we’re not here in a marked police vehicle,’ he added.

  Hiromi glanced worriedly towards Ayane, then nodded to the detective. ‘Fine. But I don’t have to stay there? I mean, I’ll be free to go home?’

  ‘As soon as we’re finished.’

  ‘I’ll get ready.’

  Hiromi disappeared into the back for a moment, then reappeared wearing a jacket and carrying her bag. While she was gone Kusanagi found himself unable to look at Ayane. He could feel her eyes on him, glaring.

  Hiromi stepped out into the hallway, following Kishitani. Kusanagi had turned to join them when Ayane grabbed him by the arm. ‘Wait.’ Her grip was surprisingly strong. ‘Hiromi’s not a suspect, right?’

  Kusanagi hesitated. Kishitani was waiting with Hiromi just outside the door.

  ‘You go on ahead,’ he said, closing the door before turning to face Ayane.

  ‘I … I’m sorry,’ she said, letting go of his arm. ‘But there is no way that she could have done this. If you’re suspecting her for whatever reason, you’re making a horrible mistake.’

  ‘I’m afraid it’s our job to look into every possibility, no matter how slight.’

  Ayane firmly shook her head. ‘The possibility that she did it is zero, do you understand? She couldn’t have killed my husband. I’m sure you understand that.’

  ‘Why couldn’t she?’

  ‘You know, don’t you? About their relationship?’

  Kusanagi gaped. ‘So you knew?’

  ‘Yes. I spoke with Hiromi about it the other day – that is, I figured it out and confronted her, and she admitted to it.’

  Ayane began to describe their exchange at the hotel. Kusanagi was astonished by what she was telling him, but not as amazed as he was to have found the two of them here, today, working in the same room. He assumed the fact that her husband was dead had something to do with it; yet he found himself utterly baffled by a woman who would maintain a working relationship with someone who had betrayed her the way her apprentice had.

  ‘I went home to Sapporo because I couldn’t bear to stay in the same house with him. I’m sorry I lied.’ Ayane lowered her head. ‘But you have to understand that she had absolutely no reason to kill my husband. You can’t suspect her of this.’

  Kusanagi blinked. What kind of person went to such lengths to protect the woman who stole her husband? ‘I understand what you’re telling me,’ he said. ‘But we can’t make decisions based on how we feel about the suspect. We need objectively verifiable physical evidence.’

  ‘Physical evidence? So you have evidence proving Hiromi poisoned my husband?’ Ayane’s eyes flashed with a hard light.

  Kusanagi sighed. He debated with himself under the weight of her stare. At last he decided that revealing the latest evidence wouldn’t cause any further complications in the investigation. ‘We found out how the poison got into the coffee,’ he said, and told her about the traces found in the kettle in the kitchen. ‘And no one is known to have been in the house on Sunday, other than Hiromi herself.’

  ‘Poison, in the kettle? How does that incriminate her?’

  ‘It’s not conclusive,’ the detective explained, ‘but as long as there exists a possibility that Ms Wakayama did put the poison into the coffee, she will remain a suspect.’

  ‘But …’ Ayane said, then faltered, at a loss for words.

  ‘Sorry, but I need to get going.’ Kusanagi gave a curt bow and left the room.

  As soon as they got Hiromi back to the station, Mamiya brought her into an interrogation room to begin questioning. Though normally this would have been done at the local precinct headquarters, Mamiya had chosen the Metropolitan Police Department instead – a sure sign he believed she would confess and turn herself in. Once she’d confessed, they would write up a warrant for her arrest, and only then take her to the Meguro station. It was a setup to give the press the photo op they wanted: a criminal being led off to justice.

  Kusanagi was waiting at his desk for the results when Utsumi returned. The first thing she said when he looked up was that Hiromi Wakayama was not the criminal.

  When Kusanagi heard her evidence, he frowned. Not because it was another ridiculous theory – in fact, it was exactly the opposite. It made complete sense. If Hiromi Wakayama had put the poison into the coffee, the junior detective explained, she wouldn’t have left the kettle on the stove after discovering the body.

  ‘So then who put the poison in the kettle?’ Kusanagi asked. ‘And don’t tell me it was Ayane Mashiba, because we’ve already established that that’s impossible.’

  ‘I don’t know who it was. I can only guess that somebody must have gone into the Mashiba residence after Hiromi Wakayama left on Sunday morning.’

  Kusanagi shook his head. ‘There’s no indication that anyone else went in there. It was just Yoshitaka Mashiba. Alone.’

  ‘We can’t say that for sure. We just haven’t found out who it was yet. In any case, there’s no point questioning Ms Wakayama any further. Not only is there no point, it might be a violation of her rights,’ Utsumi said with unusual force-fulness.

  Kusanagi was at a loss. He was contemplating the situation when his mobile phone rang. Feeling saved by the bell, he relaxed as he looked down at the phone displ
ay, only to tense up again immediately. It was Ayane.

  ‘Sorry to bother you when you’re busy. But there is something I have to tell you.’

  ‘Yes?’ Kusanagi gripped his phone tightly.

  ‘Finding poison in the kettle doesn’t necessarily mean that somebody actually put poison in the kettle.’

  Kusanagi was flustered again. ‘Why’s that?’

  ‘Well, perhaps I should’ve mentioned this earlier, but my husband was extremely health conscious, and never drank water straight from the tap. Even when cooking, I always used water from a filter. He only ever drank bottled water, and he asked me to use it when I made coffee, too. I’m sure he used water from a bottle on Sunday.’

  ‘So you think the poison could have been in the bottled water?’

  At the desk next to him, he saw one of Utsumi’s eyebrows go up.

  ‘I just thought that it might be a possibility. It just doesn’t make sense for Hiromi to have done it. And if the poison was in the bottled water, somebody else could’ve done it. Anyone.’

  ‘Well, that’s true, but …’

  ‘For instance,’ Ayane went on, ‘it could even have been me.’

  ELEVEN

  It was just past eight o’clock when Utsumi drove Hiromi Wakayama home. Hiromi had been in the interrogation room for only two hours, far less than Mamiya had anticipated.

  Ayane Mashiba’s call was the main reason he’d cut off the questioning. The widow was very clear about her husband’s instructions: the dead man had insisted that bottled water be used exclusively for all coffee making. If that was true, then all the killer had to do was poison one of the bottles ahead of time – which meant Hiromi Wakayama was no longer the only suspect.

  In any case, Mamiya had been unable to press her into making a confession. After two hours of the young woman’s tearful professions of innocence, he nodded with reluctant resignation when Utsumi suggested sending Ms Wakayama home for the time being.

  Now she sat in the passenger seat, emphatically silent. She’s probably exhausted, Utsumi thought. She had seen strong men wilt under the heat of the hard-faced detective’s interrogations. It would take a while for the tears to fade from Hiromi’s eyes. Utsumi settled in for a quiet ride. Her passenger was too worked up to say anything. And why would she, anyhow, when she knew that she was now a suspect?