Conan: Chief of Rice Flower's Science Points

Chapter 104 A strong physique is also helpful in solving cases!
Shinichi had previously thought of the murderer's method - high-frequency sounds that are basically inaudible to the human ear are hidden in the audio, and the "resonance" phenomenon is used to kill people.

After understanding this, he finally understood why the murderer had prepared a spare photo frame in advance, but still shattered the photo frame downstairs!

It wasn't that she bought one less photo, but the photo frame downstairs was broken, which was beyond her expectations...

Because the higher the frequency of the sound, the shorter the propagation distance and the stronger the penetration!
The location where the photo frame was originally hung on the first floor was almost directly below the crime scene, so when Fujimaru Yoshino was doing the experiment, the high-frequency sound waves penetrated directly and caused "resonance" in the same photo frame in the living room on the first floor.

"Fortunately" during the experiment, the photo frame on the first floor was also shattered.

If the murder actually happened, and he saw two photo frames of the same style broken at the same time upstairs and downstairs, Kudo Shinichi would be able to think of "resonance" more quickly...

What made Kudo Shinichi unconvinced was how Shiraishi discovered this first?

Afterwards, he couldn't help but ask...

"Do you mean when was it discovered that the suspect was using ultrasound? Well... it should be at the beginning." Shiraishi said as a matter of course.

"Huh?" Shinichi looked at Shiraishi blankly, as if wondering if he was bragging - when you came, you clearly didn't see any suspicious behavior from the criminal.

"The channel should have been turned off when the suspect entered the scene, right? She was too nervous at the time and did not push the knob all the way down, so there was still a little bit of weak volume still playing... When I just entered the room, I felt very uncomfortable, so the idea of ​​'resonance' was just a matter of guessing." Shiraishi explained what he felt.

That’s right, even the three young high school students, and Kanzaki, who had extraordinary hearing and was also very young, heard some “mosquito sounds” after turning the volume up to the maximum - this is also a characteristic of the human ear when hearing high-frequency sounds!
On the contrary, it no longer sounds high-pitched, only a faint "mosquito sound" can be heard.

"Huh? You can hear it too? How old are you?" Shinichi was stunned.

Bai Shi glanced at him and said, "Why does the upper frequency limit of human hearing decrease as people age? You should know, right?"

"Of course! Hearing depends on the 'auditory hair cells' in the cochlea. These cells cannot regenerate, and the 'auditory hair cells' responsible for hearing high-frequency sounds are on the outside of the cochlea. Therefore, as we age, the damage is most serious. Basically, after the age of 18, humans' perception of high-frequency sounds will begin to atrophy!"

Kudo Shinichi said this in a somewhat ostentatious manner.

"Yes, that's right... 'Auditory hair cells' are also cells. My cells are too strong, so naturally they not only have no wear and tear, but also have excellent performance, which means they can hear some sounds that you can't hear.

"Oh, actually, the sound you heard, which is within 20,000 Hz, is not caused by the 'resonance' of the photo frame glass. It is because of the quality problems of the sound system itself when it reproduces higher-frequency sounds, that some low-frequency noise is emitted, which is lower than 20,000 Hz.

"The sound that really causes 'resonance' is the sound that you haven't heard, which is actually over 20,000 Hz, that is, ultrasonic waves. When the volume of that channel is still low, only ultrasonic waves are emitted... So, good health is also a necessary quality for detectives and police officers."

Bai Shi said this and nodded seriously.

Shinichi:……

Holmes also said something similar, so Shinichi played football to exercise his body, but...

Can you be considered "healthy"? You can even hear the ultrasound! - Shinichi complained madly in his heart.

Earlier, when Bai Shi had just entered the scene, he heard a series of faint but extremely harsh sounds, and then he was looking for its source...

In this way, that is, when conducting the search "knowing that there is ultrasonic sound playing at the scene", one would naturally understand the suspect's methods earlier than Kudo Shinichi!

"Shinichi, what are you asking Director Shiraishi for advice again?" Xiaolan walked over and asked curiously.

"No, this doesn't count as asking for advice!" Shinichi immediately denied.

In this regard, Kudo Shinichi was speechless...

If it was really a "question", he would have nothing to be embarrassed about admitting.

But as Shiraishi himself said - he knew the existence of the abnormal "ultrasound", so of course it became easy to think of "resonance"!

And "hearing the ultrasound" and so on, this is obviously Shiraishi's unique "criminal investigation method" that no one else can learn.

"And what does 'cling' mean? Have I ever asked him for advice?" Shinichi corrected his childhood sweetheart.

"Xiao Hei, let's send Sonoko and the others home first." Ayako came over and said.

"Ah! No need, my home is not far away, Shinichi can take me there." Xiaolan said quickly - obviously not wanting to be a light bulb that ruins other people's date.

"It doesn't matter! It's on the way anyway!" Sonoko was not polite at this time.

At this time, Ayako was driving the car, Shiraishi was sitting in the passenger seat, and three high school students were sitting in the back. Shinichi was squeezed hard behind Shiraishi...

"Sorry, there's still some space between me and the backrest, so you have to make do with it." Shiraishi said casually. Shinichi then remembered that this guy had just been bombed a few days ago and was on the news, and he was even more impressed by the wonders of the human body.

……

Although Shiraishi was not fully recovered yet, he returned to work as scheduled the next day!

If it were someone else, not to mention the fact that he would die on the spot and be posthumously awarded two levels of police rank, even if the degree of injury was the same, the Metropolitan Police Department would have to send a new chief. After all, he would have to rest for a few months, and his physical fitness would be affected afterwards.

But Shiraishi returned to work in less than a week, so there was no need to replace him...

Shiraishi had just returned to work and was dealing with some backlogged documents when he discovered a special one - an unimportant document that Ebihara had already dealt with. It was a document from the Forensic Science Department, which was about a two-week training organized by the Metropolitan Police Department on forensic skills.

As a large police station, the Beika Police Station has three vacancies. The "Forensic Identification Department" has already had an internal recommendation and is only waiting for Chief Shiraishi's signature.

Shiraishi looked at the three names listed above, and only Kenmochi himself was relatively satisfied, the other two could only do basic work...

Also, Shiraishi wants to add Kanzaki!
His potential lies in the area of ​​"forensic identification", which is also very important in case investigation.

Like yesterday's case, there is a simple way to solve it, which is to break the glass.

If it can be determined that the photo frame was not shattered by external force from a certain point, but was shattered by "resonance", then the conclusion can be drawn in reverse.

However, Kanzaki is only talented in this area. Knowledge will not appear in the brain out of thin air. It still requires teaching and practice to truly bring out his talent.

Upon seeing this, Shiraishi immediately stood up, first went to inform former Chief Ebihara, and then went to the Metropolitan Police Department for "public relations."

On the way, he went back to the apartment and took out a refrigerated pineapple gift box - which Sato had given him when he visited him in the hospital two days ago... If there was no one else to give it to, Shiraishi would have to eat it himself.

After taking the gift, Shiraishi came to the Metropolitan Police Department and went straight to the Criminal Investigation Division...

"Hmm? Officer Shiraishi? Why are you here? I'm going to see the section chief."

A young forensic police officer recognized Shiraishi and spoke quickly.

"No need, I'm just going to visit Senior Ikariri." Shiraishi said with a wave of his hand.

"Oh, Senior Ikariri is free now and should be resting... I'll take you there!" This young forensic officer seemed to admire Shiraishi very much.

"That's great...Officer, you look unfamiliar." Shiraishi took the opportunity to talk to him.

"My name is Sakuma Akira! I'm an appraiser who just joined the company this year. Please take care of me!" Sakuma introduced himself formally.

Although it looks a bit shy, but...

Sakuma obviously admires Shiraishi Kuro very much, otherwise, as a local director, there would be nothing to care about for him.

"Hahaha, maybe I'll have to trouble you to take care of me in the future." Bai Shi said with a smile.

Not long ago, Shiraishi was just a "police captain" and was still among the front-line police officers. Of course, he did not have the bad habits of being away from the front line, and who knows, he might really need help from others in the future.

Seeing that the "legendary Police Shiraishi Shimasa" was so approachable, Sakuma became even more enthusiastic, and soon Sakuma brought Shiraishi to Igari's office.

……

This "Senior Inogari", also known as Tetsutomu Inogari, is an old police officer from the Forensic Division. He retired a few years ago, but because of his rich experience and his willingness to accept new things, he can be said to be an expert in this field!
Although police officers retire at the age of 60, they are still re-employed by the Metropolitan Police Department and continue to work on the front line. Because they are retired, people don't call them by their police rank, but just "senior."

After all, Zhu Shou is old, so he won't be bothered with ordinary cases...

Shiraishi and Igari have also dealt with each other several times. Although the "Forensic Identification Section" is under the "Criminal Department", the "Organized Violence Countermeasures Department" does not have its own "Forensic Identification Section". When something needs to be identified, they have to find the "Forensic Identification Section" of the Criminal Department.

Just now, Shiraishi saw in the document that the main lecturer of this training is Mr. Ikarii.

This time I came to the Metropolitan Police Department for "public relations" in order to request more training spots!

Since the Forensic Department has already drawn up a preliminary list, Bai Shi has no intention of removing anyone.

The Identification Department certainly would not force Kanzaki, who was a member of the Fourth Department, to participate in the Identification Training, and the current list was not a mistake...

Forcibly parachuting into Kanzaki at this time might dampen their enthusiasm - although the candidates for the Forensic Department are just "ordinary people", but... the police station relies on 90% of "ordinary people" to operate, and "ordinary" does not mean "unimportant" or "can be ignored"!
(End of this chapter)