Simulation Game
"Minami Okazaki. You are the culprit of this game, Suguru Anzai!"
I pointed to a petite woman standing in front of me.
Her face was somewhat expressionless, like a real mechanical doll.
"Noda, Fujisawa, Sano, Ōta, and Tsuchiura, these are all cities located in the Kanto region. But Okazaki is the city in Aichi Prefecture. Kazuhiro probably knew that I like castles and left this hint. Most of the castles in Japan are named after places."
"…"
Minami Okazaki's expression remained unchanged and vacant.
"Since it's you, you want to know how I got to the truth. So let me explain step by step from the beginning."
Minami remained silent. I took that as acceptance.
"In the first experiment, right about the time you got to the cafeteria, the mail arrived and The broadcast of the first experiment aired. At this point you were in the cafeteria."
"That’s right."
She nodded in agreement, but her voice lacked any inflection.
"When the third order was issued, as well as when the violator was reported, I had always wondered why the culprit sometimes used email. I thought that the killer did not have time to set the tapes, but you must have had enough time to prepare the tapes at the time of the first experiment. So there should be a reason, other than time, why the killer couldn't play the tape."
"…"
"In the first place, I wondered why the killer bothered to air the broadcast after sending the first e-mail. They could have taped both at once. The broadcast room had a timer function. If the start time is known in advance, there is no need to separate the e-mail and the broadcast. Therefore I came up with a hypothesis. Maybe the killer didn't decide when to start the game."
"Oh, then why on earth did I start at that time then?"
Minami finally began to defend herself.
"It was lunchtime at that time, so if a strange broadcast was made, someone could come to the broadcast room to check it out. If If it means taking such a risk, it's probably safer to pretend to go to the bathroom during class time and broadcast."
It seems she won't remain silent throughout the entire conversation, but will throw in counterarguments here and there.
"True. But if the tape is played while you're in the bathroom, you'll be the first one we will suspect. It was a large-scale experiment that lasted two days. In order for things to go so smoothly, your first priority must have been to avoid suspicion on your part. Besides, you would have started playing the game even in class time if the conditions were set."
"Condition? Are you saying I was taking a risk and starting a game for that?"
The fact that she's standing right in front of me makes her nothing but the culprit, yet she seems determined to play dumb.
"Yes. That condition was essential to the first experiment."
"If it's essential, wouldn't I prepare it in advance?"
"No, you just can't prepare for this one."
"What do you mean?"
"The rain. You've been waiting for the rain. The rain is as strong as a squall this time of year in this area. Hardly anyone would go outside in such a heavy rain."
"Oh my, what good is it if no one goes outside?"
"Mustard gas."
"…"
Slightly Minami's eyes sharpened. Silence is proof that I've cornered my opponent one step further, and that fuels my confidence.
"That time you unleashed the mustard gas on the schoolyard. If you play the tape and then release the gas, you might let escapees get away. So you must fill the schoolyard with gas beforehand, before playing the tape. But if the sky is clear, it opens up the possibility that someone out in the schoolyard will die before the experiment begins. That would no longer be merely an experiment. Above all, this school is old, and the sound of rain falling on the windows and ceiling is unexpectedly loud. In that kind of noise, the sound of gas going from the cylinders to the vents would be drowned out."
"Oh, so you're saying that the killer gas was already on the school grounds before the experiments began?"
"Yes. So here's what you were doing. When you saw that it was raining, you released the killer gas in a gas cylinder into the schoolyard through a vent of a classroom somewhere on the third floor facing the schoolyard. After witnessing this, you hurried to the cafeteria on the first floor and appeared in front of us. You wanted to minimize the lag between the gas release and the start of the game, so as soon as you got to the cafeteria, you sent a text message from your cell phone, which was in your pocket, to everyone at school at once with the contents of the human experiment."
"Oh, but then I can't play the first experiment on tape, right?"
"No, you didn't have to be in the broadcast room to broadcast. Because that was not the audio that came from the tape."
"But that was definitely something I heard over the loudspeakers in the school."
"Yeah, it was certainly played through the microphones in the broadcast room. But what I'm saying is, the tape in the boombox isn't the source of the sound. That was a cell phone."
"…"
It seems like I hit the nail on the head.
"An alibi to keep you out of suspicion, if you are around me when the broadcast is on, you are inevitably removed as a suspect. But you can make that alibi if you use two cell phones. In advance, set up a different phone than the one you normally use in the broadcast room's microphone. Link it to your regular cell phone, so that when you press a certain button, a recorded broadcast will play from that microphone. This way, after sending all the texts at once in the cafeteria, you could secretly operate the phone in your pocket and broadcast the first experiment from your other phone. That way, i it creates the illusion that the culprit is still in the broadcast room."
"But when we completed the first experiment, the broadcast room played a tape with different content, a status report."
"You are right. If you really were in the cafeteria throughout the first experiment, you couldn't have done it."
"What are you talking about? At that time I was confronting with my clone."
"No one saw that."
I easily refuted that excuse.
"…"
"You pretended to confront your clone, snuck out of the cafeteria, and ran up to the third floor broadcast room. In that state of panic, nobody wouldn't have cared if someone had seen you running up the stairs at a high rate of speed.
Once in the broadcast room, you removed your phone from the microphone, put the tape into the boom box instead, and set the timer. You calculated how long it takes you to get back to the first-floor cafeteria. Then you went back downstairs to the cafeteria and listened to the status report with us."
"Wait, a minute. Did you forget? The status report talks about how many are dead and how many are surviving. There's no way you can pre-record something like that."
"It can be done."
"How did I do? Are you saying that report was nonsense?"
At this moment, Minami's confusion became apparent. This might be one of the major tricks she had set up.
"No, I guess that was right. Just the way you wanted it."
"Ha, what are you talking about? Do you mean I already know how many people die and survive in the first experiment?"
"Yes. This is just another alibi you've prepared for yourself. You're starting a game like this, so you must be familiar with computer or AI, right?"
"Yes I do. What's the point if it is?"
Minami crossed her arms defiantly.
"I saw it on TV a while ago. It said AI is making great progress right now. AI was supposed to develop and evolve on its own with minimal knowledge programmed by humans. Now, apparently, AI is being bought for its useful features and is even helping to catch criminals. It is called AI simulation."
"…!"
Minami's eyes seemed to widen for that moment. It was obvious even to an outsider that she was shaken.
"It is a technology based on the case summary provided by the police, eyewitness testimonies, and the personalities and characteristics of several possible perpetrators, and the AI itself simulates the case and identifies the perpetrator. You used this, right? The content of the experiment, the number of participants, and the personality, amount of knowledge, and physical ability of each participant are programmed into the AI. All that remains is for the AI to simulate the experiment and quantify how many will die and how many will survive. You just recorded the results. And then let the AI simulate the next experiment based on the results. Therefore, you knew and could have falsified with the results of this whole experiments. So you could inevitably have made me survive."
"I get it. But wouldn't that mean that it would have been possible that someone else have done it instead of me, given your deductions so far?"
"No, others may be able to do it, but you're the only one who could have broadcast the first experiment."
"What do you mean? As I recall, the broadcast was from a cell phone. Then I think everyone could do that."
"It was raining just before I got to the cafeteria. Then it stopped a short time after I arrived. That would mean that the killer let the gas out onto the schoolyard for that short period of time in between. At that time, all the middle school students were reading in the library on the first floor, and most of the high school students were in the cafeteria."
"But most of them, right? It could have been someone who wasn't there, and I think even a middle schooler could have easily snuck out from the library."
Minami, who was still evading the issue even at this point, seemed ridiculous.
"The culprit must have been in a hurry at that time. In the middle of the rain, which never know how long does it last, you had to get air out of a gas cylinder, set the tape on the third floor, and head downstairs to the cafeteria on the first floor or to the library on the second floor. The hallways at this school are often echoing, so there is no way that you who was given detention in a classroom on the second floor before the stairs, or the teacher supervising you would not have noticed the sound of running down the hallway or down the stairs."
