Tuesday, January 5th, evening, Masatsu Hirota's house.

Noboru Hirota went to make a call, and a police officer came over and reported: "Henggou Police Department, there is a young man named Bai Cangyang outside. ”

"Let him in. The Yokozo Police Department said, "If there are people named Kazuhiro Hosoya and Michio Morioka, let them in as well." ”

When Hakura came in, he was shocked to learn that Professor Hirota had been killed.

Soon after, Kazuhiro Hosoya and Michio Morioka also arrived, and they were all shocked to learn that Professor Hirota had been killed.

"Mr. Shirakura, Mr. Morioka, what's going on with this phone recording?" the Yokozo Police Department played the phone recording again.

"I'm Morioka, I'll be there at six o'clock this afternoon, set up the chessboard and wait for me. 4:51 p.m. ”

"Professor, I'm Bai Cang, please call me back as soon as possible. "After a gap of some time," 5:31 p.m. ”

"I'm Morioka, and since you're not here, I'll go back. Really, I don't say anything early when I drink too much. 6:03 p.m. ”

"I'm Bai Cang, because I'll have something to do from tomorrow, so I'll go to you from here. 6:07 p.m. ”

The Henggou Police Department asked, "Mr. Shirakura, the first phone call was cut off for nearly a minute, why is this?"

"Oh, I just forgot to hang up. Bai Cangyang said.

"That's right. The Henggou Police Department said, "So, did Professor Hirota call you back?"

"No, I'm just here to try my luck. "I'm working as a model now, and I'm going to do a project for the magazine this time, and I suddenly remembered a photo I had taken with Professor Hirota in college, so I came over and borrowed the floppy disk from the teacher with that photo, even if the professor wasn't there, as long as my wife was there." ”

"Floppy disk?" asked the Henggou Police Department.

"My husband has a habit of saving things on floppy disks. "Favorite photos, university entrance exam questions, students' transcripts, and even his chess games with Mr. Morioka and his winning and losing records will be stored." ”

"I see. The Henggou Police Department asked, "What about this floppy disk?" He said and went to the computer desk to look at it, and found that there was no floppy disk, and then opened each drawer to look at it, and also found no floppy disk.

"It seems that this is the motive for the killing. The Henggou Police Department said, and then asked Tochiko Hirota, "How many floppy disks are there here?"

"This," said Noboru Hirota, "I don't know the specifics, but there are a lot of them anyway, definitely more than a hundred." ”

The Yokozo Police Department asked the forensic officers to check the computer, and then asked Michio Morioka, "Judging from the phone recording, have you ever been here?"

"Yes," said Michio Morioka, "I came at about six o'clock in the evening, and the door to the entrance was not locked, and I rang the doorbell and no one answered, and I thought he might have drunk too much and was taking a nap, so he came into the house by himself, but I came and knocked on the door of the study, and no one answered, and the door of the study was locked again, and I thought that the professor had slept heavily because of the wine at noon, so I went back." ”

"Professor Hirota's noon drink, how do you know about this?" asked the Yokogou Police Department.

"I was going to attend too, but I had something to do. Michio Morioka said.

The Yokogou Police Department asked, "Mr. Hosoya, why are you here?"

"My daughter recently decided to apply for Nanyang University, so I came to ask the teacher to write a letter of recommendation, but I didn't expect the teacher to seem like he had drunk a lot of alcohol, so I left a floppy disk back, which was my daughter's information. ”

The Yokogou Police Department said, "Mr. Hosoya, your daughter is going to apply for Nanyang University, so if you have a floppy disk with entrance exam questions, it will not be a problem to get in." ”

"No, no, it's not like that, I haven't even thought about it. Kazuhiro Hosoya said.

The Henggou Police Department asked, "So, when did you leave?"

"I've been here for five minutes, no, ten minutes, fifteen minutes at most. Kazuhiro Hosoya said.

"So, where did you go after that, did you have an alibi?" asked the Henggou Police Department.

"Alibi?" asked Kazuhiro Hosoya, "Is it okay for me to get a receipt from the parking lot?"

The Henggou Police Department looked at it, "The time of this receipt is about 4:22, how far is the parking lot from here?"

"A few minutes away. Kazuhiro Hosoya said.

"It's still very suspicious. Henggou Police Department said.

"Officer, you can't do this, don't forget, besides a few of us, there may be other people here. Kazuhiro Hosoya said.

"Yes, officer," asked Michio Morioka, "I have something to do tomorrow morning, can I go back?"

"Mr. Morioka, you can't go back, you said you were here just now, but in fact there are no fingerprints on the doorbell. "So please wait a little longer." ”

"W-what!" Michio Morioka was taken aback.

"How's it going?" asked Gray Plains in a whisper to Conan, "Have you figured it out?

"I already know who the murderer is, but I haven't figured out the modus operandi yet. Conan whispered, "Hold up the hard-shell notebook with three chess pieces, and then pop the key in through the crack in the door, and bounce a chess piece like bowling, so that the notebook can fall, but this only works in theory, the force is difficult to grasp accurately, if it is heavy, the key will rush out of the range of the notebook, and the telephone will not make sense." ”

"You already know who the murderer is?" Ash Hara was taken aback.

"What's so surprising about that. Conan said.

At this time, the forensic personnel reported that there were no fingerprints on the computer, and there were no travel photos, entrance exam questions, chess games and other things in it, which should have been deleted, and if you want to recover the data, you can let someone take it back and try it.

"Yes. The Henggou Police Department said, "You don't need to use the tape for the phone recording, you can also take it back and see if you can find out what the background sound is when they call." ”

The forensic officer turned on the answering machine and took out the tape, and Conan inadvertently found that the tape was full of wrinkles, and thought to himself, this is ...... Then he laughed.

Conan tugged at the corner of Dr. Akasa's coat and brought him to the side, "I already understand, you ask the police to prepare a box of the same strap first, and then cooperate with me." ”

"Okay, no problem. Dr. Asa laughed, and then went to negotiate with the Henggou Police Department.

"You really figured it out?" asked Gray Plains.

"Yes, just wait and see, the truth of this secret room murder. Conan smiled confidently.

Soon after, the tape arrived, and Dr. Asa handed it to Conan, "You do what I just said." ”

"Yes, Doctor. Conan said, then using Dr. Asasa's voice with a bow tie voice changer to use Dr. Asasa in front of him, "This room is indeed a perfect secret room, but if you use the tape in the telephone recorder and the three chess pieces, you can open this secret room." ”

"Tapes and chess pieces, is this true?" asked the Henggou Police Department happily.

"Of course, facts speak louder than words. Dr. Asasa said.

Conan borrowed a mobile phone and gloves, and as he set them up, he said, "First pull the tape out of the proper length, and then put the tape into the phone." Of course, the straps are still exposed. Then straighten the exposed strap and walk out of the door, then pass the strap through the ring on the key, then leave the key outside the door, take the rest of the strap back to the place where the notebook fell in the room, and then arrange the three chess pieces of the same height into a triangle, use the front end of the strap to cover the chess piece closest to the phone, and then put the notebook on it. ”

"It's all nonsense, you're going to use the force of the strap to pull the key, let the key knock the piece down, and let the key come down from the strap by the way. "However, the base of the chess piece is very stable, and with the force of the key touching the chess piece, the key cannot knock over the chess piece at once, but will be pulled out of the notebook with the chess piece." ”

"What if it's upside down?" Conan laughed, "The next step is to turn the pieces upside down, and although the top of the pieces is round, a sturdy hard-shell notebook like this should hold up." ”

Conan set up the scene, then went out to bring the door and used the mobile phone to call the landline phone in the room, "So the telephone recorder turned on, and the tape was rolled, and this force caused the key to pass through the gap under the door, and into the notebook placed in front of the house telephone, and hit the chess piece, and the chess piece was unbalanced, and the key was left under the notebook, and if the telephone recorder continued to be turned on, it would completely roll back into the tape, and the evidence was gone." Then he went back to his room and asked, "How's it going?"

"See for yourself. Gray Yuan laughed, "The upside-down chess piece can't jam the strap at all, you don't even count the pull that the upside-down piece can bear, and the strap pulls the chess piece down before the key reaches the bottom of the notebook." ”

Seeing that the key card was behind the hard-shell notebook, Conan was taken aback, "How can this be?"

"Dr. Asasa, is that your theory?" asked the Yokogou Police Department.

"This ......," Dr. Asasa sweated.

"Leave it to me," Gray Yuan said with a smile, "It's actually very simple, children can play, just push the key in and let the laptop fall off." ”

"Simple?" the sweat of the Henggou Police Department fell.

"Of course. Ash Yuan Ai put the key on the ground, pushed it a few times with his hand, tried the strength and the sliding distance of the key, and then also used the three chess pieces in reverse to put the notebook in front of the phone, and then also pulled out a long enough belt, but the strap did not bypass the key, and the top of the belt was set with the chess pieces in the corners.

"What are you ......?" asked the Henggou Police Department.

Gray Yuan went out and closed the door, "Look at it." As he spoke, he pushed the key through the crack in the door, then pulled the strap, then opened the door and went in, seeing that there was only the notebook, and immediately laughed, "How about it, it's not difficult to keep the key in a straight line and slide two meters on the ground, as long as the force is not too great, the notebook that falls because there is one less piece pulled away by the strap can hold down the key so that it won't run out." ”

"What if it doesn't work out?" asked the Henggou Police Department.

"Isn't there a telephone behind it that is stuck in the ground? If the power is too great, the key rushes through the notebook, and it rushes under the telephone, and then it gets stuck underneath. "And there's something simpler. ”

"Simpler?" asked the Henggou Police Department.

"If you can pass the key through this door, the wire will definitely pass," said Gray Yuanwai, "and if it is two meters, there is a kind of telescopic tape measure that is two meters long, and you can use that key to push it in, and you don't have to pull the tape tape." ”

"Yes, yes, it's very simple. The Henggou Police Department said happily, and then said, "The murderer is you, Mr. Bai Cangyang, after you implemented this set of techniques, you lay on the door to make a phone call, and kept looking at the tape to answer the inside of the recorder, and then hung up the phone, so there is a blank in your message for nearly a minute." ”

"I told you, I just forgot to hang up. Bai Cangyang asked rhetorically, "Why did I do that trick just now? Besides, if I was the murderer, why would I go out of my way to come back to the scene?"

"Huh, this ......" the Yokozo Police Department looked at Dr. Asasa.

Dr. Asasa hurriedly waved behind him, signaling Conan to stop chatting with Gray Plains and hurry up.

Ash Yuan Ai walked back to Dr. Asasa and whispered to Conan behind him, "How is it? I now know who the murderer is." ”

Conan muttered, "The tape that uses the tape and the chess pieces that turn the chess pieces upside down are all things I think of, and they can only be considered a tie." ”

"Alright, alright," Gray Yuan Wai chuckled, "I'll let you be your little brother as a sister." ”

"By the way, how old are you?" asked Conan in a whisper.

"Secret. Gray Yuan laughed.

"Damn. Conan complained, then saw Dr. Asa waving behind him, and immediately used Dr. Asasa's voice with a voice-changing bow tie and said, "The murderer is Mr. Yoshi Shirakura, that's right, after he killed Professor Hirota, he found something from this house to clean up the evidence and set up the scene, but he didn't have an alibi, so he wanted to reduce his suspicion and create a suspect." ”

"Manufacturing?" asked the Henggou Police Department, "how is this made?" ......