Chapter 160: Investigation

The facts do not contradict Akikawa Kyousuke's judgment.

After Conan and Haibara Ai realized that the deceased had died from hydrogen sulfide poisoning, they immediately asked the police to measure the hydrogen sulfide concentration in the air around the women's hot spring area.

The result was [0.001%], significantly lower than the lethal concentration of [0.07%].

These test results revealed two key points.

First, the murderer did not commit the crime where the body was found.

Second, there was no danger for the police to conduct an on-site investigation in this area.

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Akikawa Kyousuke did not witness the police measuring the hydrogen sulfide concentration in the air.

However, he deduced the results based on the reactions of the police at the scene, as well as Conan and the others.

Moreover, Akikawa Kyousuke also made another judgment.

The murderer chose to use hydrogen sulfide to kill the victim so that the gas, which is commonly found in Hakone due to its natural hot springs, could disguise the murder method.

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Akikawa Kyousuke was fully aware of the concentration required for hydrogen sulfide to cause acute poisoning.

Thus, he determined that this could not have been an accident.

The murderer must have deliberately produced a high concentration of hydrogen sulfide gas to kill Takeshi Furusawa.

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However, the most significant difference between hydrogen sulfide and potassium cyanide, another toxin, is that hydrogen sulfide is a gas.

Being a gas, it can easily affect those nearby.

Additionally, hydrogen sulfide is heavier than air, meaning that, in the absence of wind, it tends to remain in low-lying areas.

If the murderer failed to control the amount of hydrogen sulfide released, everyone in the room where the murder took place would likely have been affected.

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This is why Akikawa Kyousuke said that if the murderer were willing, they could kill all the residents in the surrounding rooms, including themselves, at any time.

Apparently, Conan reached a similar conclusion.

He promptly asked Dr. Agasa to urge the Kanagawa Prefectural Police to investigate the suspects and apprehend the murderer as soon as possible.

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"The last hour for general tourists to access the hot spring area is at 8:00 p.m., and after 9:00 p.m., the hot springs are off-limits to non-staying guests."

"Therefore, the murderer must either be a staff member at the hot spring inn or a guest who stayed here last night."

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A police officer from the Kanagawa Prefectural Police Department looked at his notebook and silently repeated what appeared to be Dr. Agasa's reasoning, though it was actually Conan's.

The officer first sent police to check the alibis of the hot spring inn staff on duty last night.

The results confirmed that none of the staff were suspected of the crime.

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The second step was to review the surveillance footage.

To protect guests' privacy, Kosen-an does not have cameras in the hallways near the rooms.

Instead, cameras are installed in the elevators and stairwells on each floor.

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After the police learned from Dr. Agasa that the murderer must have committed the crime in one of the rooms, they focused their attention on the surveillance footage from the guest room stairwell and elevator.

They soon found a highly suspicious scene in the stairwell footage from the second floor:

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At around 1:20 a.m., a man dressed warmly was seen dragging a black suitcase down the stairs.

The police immediately suspected this man of being the murderer transporting the body.

After all, the individual dragged such a heavy suitcase and chose the stairs, likely to avoid the elevator's surveillance.

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The surveillance footage soon confirmed the police's suspicions.

The well-dressed man returned to the second floor via the stairs about twenty minutes later.

However, the suitcase was gone when he returned.

It was clear that the man had discarded the suitcase after disposing of the body.

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Subsequently, the police questioned the staff responsible for cleaning the women's hot spring area at Kosen-an.

It was confirmed that they had finished cleaning by 12:30 a.m. and had not seen any body at that time.

Thus, the police identified the murderer as a guest staying in the standard room area on the second floor.

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"We have investigated all Kosen-an staff and confirmed that none of them could have committed the crime."

"Secondly, through investigation and surveillance, it has been determined that the murderer is a guest staying in the standard room area on the second floor."

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Conan deduced from the method of the crime that it was a premeditated murder, leading him to believe that the murderer likely knew the victim.

This narrowed the suspects down to four theater actors, including Akikawa Kyousuke.

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Two of the four actors were local residents of Kanagawa Prefecture and not staying at Kosen-an.

Thus, the only suspects were Akikawa Kyousuke and a man named Shoichi Matsutani, who played the monster in the play.

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Additionally, the first person to discover the body was a woman named Mayumi Motoki, who also stayed on the second floor.

The police temporarily focused their suspicions on these three individuals.

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"The only camera that captured the murderer was the stairwell in the second-floor guest room area. However, because the murderer deliberately concealed their figure, it's challenging to determine their gender and physique."

"But the murderer disposed of the body between 1:20 and 1:44 a.m., and none of you three have an alibi for that time."

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Mayumi Motoki, the first to discover the body, suddenly appeared upset after hearing the reasoning given by the police in her presence.

She looked at the police officer with some irritation and loudly said:

"Why am I also a suspect?!"

"I don't even know the deceased!"

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The police responded:

"That is just your unilateral statement, Miss Motoki, and it does not prove that you truly didn't know Mr. Furusawa."

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Mayumi Motoki became visibly angry and retorted:

"But if you follow your logic, then everyone staying on the second floor should be suspects."

"After all, Officer, how can you tell whether someone genuinely didn't know the deceased or is simply lying?"

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Shoichi Matsutani, the suspect who played the monster in the play, nodded in agreement with Mayumi Motoki's statement:

"That's right! Anyone could have known Mr. Furusawa!"

"You're accusing me of being a suspect just because I acted alongside Mr. Furusawa? Isn't that absurd?"

"What motive would I have? What good would it do me if he died? I wouldn't become the lead actor, and my job would end prematurely!"

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Both suspects, Mayumi Motoki and Shoichi Matsutani, were visibly dissatisfied with the police's suspicions.

Everyone present unconsciously turned to look at Akikawa Kyousuke.

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They clearly expected Akikawa Kyousuke to voice his dissatisfaction with the police just as the other two had.

Then, they saw the strikingly handsome, chestnut-haired actor look puzzled at Mayumi Motoki and Shoichi Matsutani.

He then said:

"Speaking of which, Mr. Matsutani and Miss Motoki, you two should know each other, right?"

"I thought I saw the two of you yesterday discussing what kind of gas to produce."

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Akikawa Kyousuke's statement caused the expressions on Mayumi Motoki and Shoichi Matsutani's faces to freeze instantly.

The two of them stammered in confusion almost simultaneously:

"Ah—what?!"

"What are you talking about?!"

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(End of the Chapter)