１．Ｓａｔｕｒｄａｙ　Ｍａｒｃｈ　２３，　２０１９

Picking up Kira near Tokyo Station, Maruta stepped on the gas pedal again. In the plaza in front of the station building, people, eager to make memories, are posing with their smartphones, each in their favorite posture.

"It's been almost a year now."
"What's the story?" Kira asked as he buckled his seatbelt.
"It's about a ten-minute walk from here. Where I first met you and Silva-san."
"Come to think of it, yes. One year already. That's fast."

The office area is less crowded on weekends, so there are many secret spots in the city. A café can be as good as rented out, if it is just before closing.

The time is 13:00. Maruta does not say, "If you like, we can go into a nice place somewhere tonight," to Kira wearing what can't be distinguished as pajamas or everyday clothes.
Maruta decided instead to bring up that abominable common topic.
"Kira-san, you remember the video we saw the day before yesterday. Opportunities for killing were available to all participants, including Silva-san."
"Including Silva?"
"Yes."

When they approached a traffic light, Maruta hit the stiff brake. "Of course, I mean including the case of Silva's suicide."
Hearing this, Kira looked unflattering. Maruta knew in advance that Kira would not understand this story. He carefully put out each word as if he were presenting an assignment.
"It is just one of the possibilities. There is not a single piece of evidence yet."

The car starts to drive off, and Maruta says more. "The person who had the earliest opportunity to kill, you see, was Kirvy-san. He entered the room with Silva-san shortly before he was to be shut in."
"Kirvy had not been in Silva's room for a minute, had he?"
"Of course, the fact is. He had the opportunity to kill, albeit for a short time, is what I mean."
"Did you hear Silva's voice through the gap in the door right after Kirvy left?"
"It was heard very well. If the end result is that Kirvy-san committed a deft murder and played back Silva's voice with some sort of sound equipment, it is utterly ridiculous."
"In that case, it would mean that Kirvy pre-recorded Silva's voice."
"It should be taken only as a possibility. I also think that it doesn't need to be taken up again, though."
"Furthermore, a dead Silva can't lock the door from the inside."
"No, he can't. You are correct."

The car weaved its way through the buildings. "Do you remember who was next?"
As Kira was about to think about it, Maruta said first. "The obvious one is Number 4-san."
"Is it when he changed the battery?"
"He swore he did nothing, but we can't rule it out as one of the possibilities."
"He said that the time the images were interrupted was quite short."
"He said so himself, and now we have to trust him. Well, the video certainly didn't look like it had been interrupted for ten or twenty minutes."
"In that case, again, that doesn't explain the inside lock."
"No, it doesn't. If Number-san 4 had the occupant of the room unlock the door and kill him, he cannot lock the door and go back again."

"Then Captain is next." Kira began to understand the story.
"Yes. Captain was the first person to break through the door to the right room and enter."
"It's possible that Silva was alive just before those guys rushed in and he was strangled to death by the first captain to enter the room."
"That story is also quite implausible, but there's no way to say there's no chance of it happening."
"In that case, the problem of the locked door would go away."

After getting on the Metropolitan Expressway, Maruta relaxed his shoulders. Now he can proceed with his thoughts without having to pay much attention to pedestrians and parked cars on the street for a while.
"The opportunity for Mont Blanc-san is," Maruta was in the middle of saying this when Kira put his words to him.
"That's when he was on artificial respiration."
"I could faintly hear his breathing through the speakers, although it did not show up well in the video."
"Does that mean that Silva was alive when he was carried out of the house?"
"In this case, it does. There is a possibility that he pretended to do artificial respiration and put his hands on his neck."
"For a moment, I saw Silva's dead body in the video, but if that was an act..."
"That's on par with the Best Actor award at film festivals. So this case is also ridiculous enough."

"When is the opportunity for Shaggy?" Kira turned his head to the side.
"That would be when he went out to buy something."
Kira's question drifted there as air of halt. Before that could come out as words, Maruta said.
"This is another classic method, but if 'the entire window frame was removable', he could do it."
"Are you saying that the window in the right room was removed along with the frame?"
"Yes. And, in this case, after carrying out the killing in the room, he went back out and put back the frame with the window still on."
"Wouldn't that mean that everyone who went outside while Silva was in the room had an opportunity to do the same?"
"That's exactly right. In fact, in this case, all the members had the opportunity to kill, not just Shaggy-san. They were outside, or out of the frame of the filming camera, at least once while Silva-san was in the secret room, you see."
"That case, too, is pretty much impossible."
"I agree with you, Kira-san."

Kira spoke up like a child who wanted to show off his answers.
"Parts of the house remained unburned. So if the window frame was removable, the police who examined the wreckage would have seen through the trick long ago."
"I'm not sure we can say that much, though. The room to the right where Silva-san was was almost completely burned down. It is not known now whether the window frame remained unburned and inset in the wall. Also, after Captain pried open the door and went inside, he examined every inch of the room, including the window."
"Couldn't it be that Captain was pretending to investigate at the time?"
"Of course, that is not inconceivable either."

Maruta, then intensified his speech.
"If the culprit is alone, as I have just said. If there is more than one killer, as you just pointed out, for example, Shaggy-san could remove the window frame and kill the victim, and Captain could act to make it look like the window frame was fixed when he found the victim. However, when there are two culprits, there are 15 possible combinations of culprits, and when three, there are 20 possible combinations[*1], which is a large number of cases. So, let's stop with these standard prehistoric reasoning."

"Maruta-san," Kira said seriously. "I know Number 4 changed the battery in the process."
"Yeah,"
"Is it not possible that the dates of shooting the images before and after that are different?"
Maruta snorted in admiration and thought for a moment, looking straight ahead.
"That is, if all five of Tokyo Spread were in cahoots. In that case, all five of them would have to act out the play so that the images before and after the battery change would be connected. But I don't think it will create new ways to kill."

"Also, as is often the case in TV dramas, there's the question of where the murder weapon went."
Maruta just gushed over the drop in quality of the story.
"I doubt the murder weapon will be an issue in this case. It was a 'string thing' that was used for strangulation. After the murderer uses it to kill, he can put it in his pocket, throw it away somewhere later, and that's the end of it. No wonder the weapon was never seen again. Of course, this would not be true if Silva-san committed suicide. Rather, much more puzzling are 'The missing ring,' 'The blue fire,' and 'The only door in the middle room that was not opened from the beginning'. Because at the moment, we are not able to tie them to the case and explain them rationally. Besides, I think there were a few other points worth noting. I haven't quite got them all sorted out yet, though."

[*1]:The number of Silva and Tokyo Spread to arbitrarily choose two from a total of six is (Silva, Captain) (Silva, Kirvy) (Silva, Shaggy) (Silva, Number 4) (Silva, Mont Blanc) (Captain, Kirvy) (Captain, Shaggy) (Captain, Number 4) (Captain, Shaggy) (Kirvy, Shaggy) (Kirvy, Number 4) (Kirvy, Mont Blanc) (Shaggy, Number 4) (Shaggy, Mont Blanc) (Number 4, Mont Blanc), these are the fifteen ways.
In the same way, there are twenty ways to choose three people from six. Furthermore, there are fifteen ways to choose four from six. Six ways to choose five from six. There is one way to choose six persons from six.