When Gao Yuan understood the method of the secret room, he knew that this time Suzuki Sonoko was not simply missing, but more likely to have been kidnapped! If it is just a disappearance, I am afraid that even if the police are notified in such a short time, it will not be taken seriously, but if it is a kidnapping, the nature is different.

So, after Gao Yuan figured this out, he immediately secretly sent a text message to Officer Twilight, asking him to quietly bring someone over - judging from the current situation, the other party should not have enough time to take people out of the school, but he still has no clue where the person is hidden.

However, looking at these two girls from Didan High School, Gao Yuan was a little curious, if this is the method, then it can be implemented at any time, why did he choose to do it today? And it's a weekend, how can the other party be sure that the garden will come to school today?

Suddenly, Gao Yuan thought of the situation when he met the garden at the school gate before - the garden heard that there would be handsome guys in this kendo competition, so he came to the school to watch! And it just so happened that after the garden came, Kudo Shinichi went back.

Kindness? That's right! Shinichi Kudo is back!

The biggest difference today is that Shinichi Kudo went back first! As a premeditated kidnapping, and the target is still a friend of a detective, then as the mastermind of the operation, you definitely don't want a detective to be present!

But Suzuki Sonoko was kidnapped, and this matter will inevitably be known by Kudo Shinichi in the end, so Kudo Shinichi's temporary absence can only help the initial action at most - is this very important?

In other words, this plan did not dare to be implemented while Shinichi Kudo was there? Afraid of being seen through? As long as it is seen through, the plan fails? If so, then now that I understand the tricks of the secret room, shouldn't I think about the whole thing more simply?

Before, I thought that there might be an accomplice to help me in the whole thing and take Suzuki Sonoko out of the old school building, but it shouldn't be too late to send him out of the school. So I called the police over, but I didn't dare to let the police blatantly investigate, because I was worried that Suzuki Sonoko was still in their hands, and if they acted rashly, they might pose a threat to Suzuki Sonoko.

But if you think about it more simply—could it be that people haven't been taken out of the old school building at all?

Judging from the current observation, in this old school building, where only the art club has activities today, one of the entrances and exits has obviously not been opened for a long time, and the other is facing the playground, even if there is a helper, it is difficult to take people out, so it is possible that people are actually still in this old school building! If that's the case, are accomplices really needed?

"Have you inspected all of the old schoolhouses?"

Gao Yuan asked the two girls.

"I've basically searched for everything I can find, but I haven't found Yuanzi classmates."

Moemi Nakagawa said.

Hearing this, Gao Yuan pretended to ponder, and then spoke: "En...... That's right. At present, it cannot be ruled out that Suzuki will go somewhere else. Nakagawa-san, why don't you look elsewhere? Ninagawa-san, take me to the old school building again. ”

"Okay."

Ayako Ninagawa responded.

"Why don't Ayako go somewhere else. I'm familiar with this old school building, so I'm going to take a closer look. ”

Moemi Nakagawa said.

"That'll do fine."

After receiving the answers of the two, Gao Yuan immediately turned around and walked towards the old school building, with his back to the two of them, and a smile appeared on the corner of his mouth!

At this time, the Fujimaru family, Heiji Hattori and Shinichi Kudo had already arranged the facilities in the house and were ready to start the case repeatedly.

"Here we go! Everyone's got it! ”

Heiji Hattori said, swinging the baseball cap he was wearing backwards back to the front, and then went to the mixer and started playing music.

The loudspeaker in the living room played loud music, the same as what everyone heard outside the house at the time of the crime.

It's just that after a while, nothing happened.

"What's going on, Heiji. Just hearing the music, not hearing any strange sounds, nothing happening! ”

Toyama and Ye asked.

"What's going on! This should be the method! ”

Seeing that there was no expected result, Hattori Heiji was also a little surprised, put his hands on the mixer, looked at the various buttons on the mixer, and said puzzled.

And Kudo Shinichi on the side couldn't help but think about such a result, and then, the two thought of something at the same time, raised their heads, and glanced at each other.

"That's it!"

Suddenly realized, Hattori sighed.

Then Hattori and Kudo each went in different directions, Kudo came to the mixer, and Hattori walked behind the wall where the art photos were hung.

Behind the wall, on a shelf full of various audio equipment, Hattori found a speaker that was not connected to the power supply, and said with great joy: "Sure enough!" ”

Kudo, on the other side, turned off the sound of the music in front of the mixer.

"Why turn down the music?"

Xiaolan asked a little puzzled.

"So, guys, let's show you now!"

"The only truth!"

Hattori and Kudo sang and said in harmony, making the two of them look at each other and smile.

Kudo controls the buttons of the mixer and turns on the volume of a certain frequency band, but everyone doesn't hear anything, but soon, an accident happens!

In the position of the original broken art photo frame, the art frame of the hostess of the same size that had been replaced with a repaired photo suddenly began to vibrate.

"Hey! Another superpower! ”

Seeing such a scene, Xiaolan couldn't help but think of the live TV broadcast she participated in not long ago.

"Fool! How can it be! ”

Kudo said, "It's time to start!" ”

Then I turned up the volume of this band to the maximum, and then the glass of the art frame was shattered! The shards of glass were all scattered on the sofa. This scene made Xiaolan and He Ye startled!

"Why! Obviously nothing was done! ”

Xiaolan asked suspiciously.

"Natural frequencies. That's how glass breaks! ”

Kudo explained, but some of the people present apparently didn't understand.

And after hearing this statement, Officer Miwako Sato, who was on the side, understood the key.

"Natural frequencies? Is it resonance? ”

"That's right. Everything has its own frequency that is prone to vibration. The music playing in this room has been added with frequencies that only cause the frame to vibrate. ”

"In order to make it emit a specific frequency, the speaker that still exists behind the frame is passive."

Kudo's followsuit part explained the principle of the incident one after another, but Kazuha still didn't understand: "But I didn't hear any sound!" ”

"Fool. The sound of more than 20,000 hertz is inaudible to ordinary people! ”

Hattori explained.

"The glass on the picture frame is like a swing in the park, the harder you push it, the more you shake it."

In the same way, with the frequency of the feature, the vibration of the glass will become more and more vibrating, and when it can no longer bear it, the glass will break! It was with this invisible murder weapon that the prisoner killed Miss Sunrise. ”

"And this invisible murder weapon is resonance!"

Kudo and Hattori said one by one, and Fujimaru Kazuo on the side hurriedly explained: "Wait! I've never used this frequency! And to this day, the song has never shattered the glass! ”

After hearing this, Hattori couldn't help but smile, "Of course! That's the guy who knew you'd cover up an affair with this tune, and made a CD with a specific frequency! yes, Toiru! ”

"That's right! You're the culprit! ”

As he spoke, Kudo and Hattori pointed at the prisoner at the same time - Fujimaru Yoshino!