Kirigiri made herself comfy as she spoke, leaning back in the armchair.
"Wait a minute—you know who this true culprit or whatever is?"
"I wonder?" Kirigiri asked, a reserved, mysterious smile appearing on her lips. "Now, let us continue the discussion, and recall what has happened since the start of this incident."
"From the start?"
"Yes—starting with the question of when you and the others were given the sleeping pills."
"Ohhh, now that you mention it! 'Fainting Drugs' is written on the challenge letter!"
"No, the sleeping pills and fainting drugs are two different things. I believe the fainting drugs were what I inhaled from the handkerchief. But at some other time, you and the others unwittingly consumed sleeping pills."
"When exactly was that? I was so careful, I didn't even touch anything that was in the fridge!"
"You drank a can of coffee in the van, didn't you?"
"Oh!" I suddenly cried out. "The can of coffee I got before we left the station! Are you trying to say there were some slow-acting sleeping pills in there?"
"Yes. I cannot think of anything else."
"So that was it... Does that mean the driver is the culprit?"
"No, the driver went back down the mountain. I find it hard to believe he would come back covertly to sneak into the building. You confirmed that no outsiders went in or out yourself, didn't you?"
"I-I guess I did."
"The driver was acting under instructions from Yoshizono Ooe. Giving you that can of coffee was part of those instructions."
"So the murder plot had already started by then... I was too careless."
If only I had noticed back then, then maybe I could have stopped it from happening! I bit my lip.
"I believe the sleeping pills were portioned out such that they would take effect once we had reached the building. Though I don't know why they weren't mentioned in the challenge letter with the rest..."
"You don't think they were all lumped together under fainting drugs?"
"I wonder?" Kirigiri cast her eyes downward, pensive. "In any case, all of us temporarily lost consciousness. It can be assumed that the dismemberment took place during that period of time."
No doubt the murder proceeded as intended. Under those circumstances, there had to be some meaning behind the fact that Kirigiri and I weren't killed. According to Kirigiri, that reason was apparently so that I could play the detective and she could play the culprit, but...
"After arriving here, we carried out a careful investigation of the indoors," Kirigiri said, looking around at it. "As a result, we learned that there was no one else here but us—not even Ryuuichirou Kiba or Yoshizono Ooe."
"Mm-hmm."
"Then, after we regained consciousness, we investigated inside the building again, once again concluding that there was no outsider present. There is no trace of anyone exiting or entering. Do you have confidence in this testimony, Yui-oneesama?"
"Of course. That was the conclusion of a careful investigation."
"The five of us were the only ones in the building."
"Right. No doubt about it." I nodded emphatically.
"The culprit arranged this situation so that you would make an error in your reasoning. There's no doubt about that much. It's inevitable that you would indict me as the culprit, isn't it?"
"I... can't think of anyone else."
"I see. Then, allow me to refute that assumption," said Kirigiri, attempting to sound mature. "I am not the culprit. The culprit is someone other than you or me."
"A culprit other than us... But you agreed that it was only the five of us in here, didn't you?"
"Yes."
"But you're still saying that the culprit is someone else?"
"Yes."
"You don't mean—the culprit is one of the three dead people?"
"I do."
"Th-That's unthinkable! It's impossible, no matter how you think about it. Weren't they all dismembered? They couldn't possibly be playing dead. Or do you mean one of them committed suicide? That possibility disappeared when they had all their severed body parts rearranged. Someone other than the three dead people had to be there to rearrange the parts like some twisted puzzle."
"Yes. The question is, who?"
