Chapter 165: Advancing Step by Step

After hearing Dr. Agasa's words, Shoichi Matsutani and Mayumi Motoki suddenly showed extremely frightened expressions on their faces.

"Wait, what are you talking about?"

"I don't understand what you mean by using bath products to kill someone!"

"Miss Motoki and I don't know each other at all. You wouldn't believe the nonsense this person is saying, would you?"

Shoichi Matsutani pointed at Akikawa Kyousuke and spoke loudly to Dr. Agasa.

---

"Yes!"

"I don't know this person at all. How could I possibly help him kill someone? Don't joke around!"

"I just stepped on a dead body while bathing this morning. This artist has deceived all of you!"

Mayumi Motoki similarly shouted in response.

---

The police officer from the Kanagawa Prefecture Police approached the two of them with a serious look and said:

"We found a leather prop case used for theatrical performances in the room of the deceased, Furuzawa Takeshi, and detected a high concentration of hydrogen sulfide inside it."

"According to Dr. Agasa's analysis, the murderer created hydrogen sulfide inside the hood and then placed it over Mr. Furuzawa's head, thus killing him with a small amount of hydrogen sulfide gas."

"Mr. Furuzawa was supposed to return the hood to the actors' dressing room after yesterday's play, but it ended up in his room, indicating that the murderer deliberately removed it to commit the crime."

"Mr. Matsutani, as an actor in the play, even if you entered the dressing room, no one would suspect you," the officer added.

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"No, no, no! Akikawa Kyousuke is also an actor! Why are you only suspecting me?"

Shoichi Matsutani, clearly unable to accept the officer's statement, pointed at Akikawa Kyousuke and shouted in protest.

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"Because among all the suspects, only Mr. Matsutani had bath products found in his room."

Dr. Agasa spoke at that moment, addressing Shoichi Matsutani.

"Forensic police have taken the hood to test for the corresponding chemicals."

"I believe the components of the bath product you used, Mr. Matsutani, will be detected in it, correct?"

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"But even if that's the case, what does it prove? Couldn't Akikawa Kyousuke have bought the bath product and thrown it away after using it?"

"It's outrageous that you're doubting me based solely on a bath product!"

Shoichi Matsutani clearly couldn't accept Dr. Agasa's statement and grew increasingly agitated.

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"This bath product is specifically designed to replicate the open-air hot springs of Kosenan. Among the 10,000 buyers, no one else would use it in Kosenan itself like you, Mr. Matsutani."

"It's like visiting a famous restaurant after traveling thousands of miles and refusing to eat the freshly prepared dishes offered there. Instead, you spend money on semi-prepared food sold in the same restaurant to take away."

"This behavior seems quite unreasonable."

---

"So what if I don't like bathing with other people? Who says you're required to use the open-air hot springs just because you're staying at a hot spring hotel?"

Shoichi Matsutani continued to argue.

---

"Mr. Matsutani, even though the components in the hood have not yet been tested, you've already admitted that the bath product inside the hood belongs to you."

Conan, using his voice-changing bow tie, spoke coldly.

Shoichi Matsutani was left speechless after hearing those words.

---

At that moment, Akikawa Kyousuke also spoke:

"I've never bought any bath products, Mr. Matsutani."

"If you don't believe me, you can check the store's surveillance cameras."

As Akikawa Kyousuke spoke, he pointed to the large sign at the entrance to the souvenir shop area: "Under Surveillance – Theft is Illegal."

To prevent theft in the crowded souvenir shop at Kosenan, surveillance cameras were installed in the shopping area.

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"Although I'm not sure how bath products are related to the murder, if you compare the surveillance footage, you can determine if I also purchased any bath products."

Akikawa Kyousuke said this to Shoichi Matsutani with an innocent look.

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"All the evidence points to you, Mr. Matsutani, as the one who secretly removed the hood of the Masked Superman and used bath products to create hydrogen sulfide gas, killing Mr. Furuzawa."

"You're the one who owns the bath product, Mr. Matsutani. You're the one who could reasonably enter the dressing room and take the Masked Superman's hood."

"Mr. Matsutani, you perfectly meet the conditions of the murderer."

"Do you have anything else to say, Mr. Matsutani?"

Conan took a step closer, continuing to press him with questions.

---

"How can someone kill with just a bath product? I'm just an actor—I know nothing about this kind of thing!"

"Besides, as you said, hydrogen sulfide gas can't be created with just bath products, right?"

"I have nothing that could be used to make hydrogen sulfide gas from bath products!"

---

Shoichi Matsutani's words made Akikawa Kyousuke realize something.

"As expected, he found another acidic substance in the hot spring hotel."

"This is exactly why Shoichi Matsutani is so confident that what he's done will never be exposed."

"The other chemical must be readily available and completely unsuspicious!"

---

Once the bath product containing sulfur was determined, the remaining reagents needed to produce hydrogen sulfide gas were very simple.

Akikawa Kyousuke could think of at least four items in the hotel containing acidic components that could react with sulfur in the bath product to generate hydrogen sulfide gas.

The easiest to obtain and least suspicious item among them was the laundry detergent available in the laundry room on each floor.

When sulfur-containing bath products are mixed with acid-containing laundry detergents, the sulfur decomposes and releases hydrogen sulfide gas.

Conveniently, there were no surveillance cameras in the hallways near the guest rooms, so entering and exiting the laundry room wouldn't be captured on camera.

---

Akikawa Kyousuke's assumption was confirmed in the very next moment.

The short-haired brunette standing beside Conan whispered:

"It's laundry detergent."

"Mr. Matsutani, the other thing you used to react with the bath product was the laundry detergent from the laundry room!"

---

After hearing Haibara Ai's words, Shoichi Matsutani's expression grew even darker.

He continued to maintain his innocence, but his rebuttals became increasingly weak and unconvincing.

"I don't know what you're talking about. Do you have any evidence that I did it?"

---

At that moment, the sound of an ambulance siren broke the tension.

Moments later, several emergency personnel entered and carried out Moto Kojima, who had fallen unconscious from hydrogen sulfide poisoning.

The Kanagawa Prefecture police officer then spoke in a deep voice:

"The boy was poisoned and fell into a coma due to the hydrogen sulfide left by the murderer in the Masked Superman's hood."

"Although this was caused by the boy's carelessness, remember that the murderer who created the hydrogen sulfide in the hood is also responsible!"

---

After hearing this statement from the police, both Shoichi Matsutani and Mayumi Motoki's faces turned ashen.

They had not expected anyone else to be harmed by the hydrogen sulfide.

The police observed their reactions and, sensing the moment was right, turned to their subordinates and whispered:

"Separate Mr. Matsutani and Miss Motoki for interrogation."

"Under the Prisoner's Dilemma, I believe one of them will confess."

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(End of the Chapter)