Transmigrated into Conan, his ability is Rhodes Island

Anhydrous ethanol is a high-purity aqueous solution of ethanol. Under normal circumstances, an ethanol solution with a concentration of 99.5% is called anhydrous ethanol. The biggest difference between anhydrous ethanol and commonly used disinfectant alcohol is their concentration.

“Anhydrous ethanol? Do you see anything wrong with it?” The three police officers had just seen Akihara Kazumitsu walking towards them without saying a word, so they quickly followed him. Hagiwara Kenji stopped beside him and looked at the label on the bottle in his hand. “The cleaners use it to disinfect the underground parking lot—it’s a bit strange, but it doesn’t make perfect sense.”

The "strangeness" he referred to mainly lies in the fact that alcohol is more commonly used for medical disinfection, with 75% alcohol being the most effective. In places where disinfection requirements are not high, chlorine-based disinfectants (such as 84 disinfectant) are used more frequently.

Akihara Kazumitsu casually shook the bottle, using this method to measure the remaining anhydrous ethanol. Judging from the sound, it could be estimated that it had been used at least once before.

He turned the bottle over and glanced at the production date; it was two days ago.

Seeing that Akihara Kazumitsu did not answer, Matsuda Jinpei's eyes flickered, and he voiced his speculation. "You mean, this is an 'accelerant'?"

Akihara Kazumitsu put down the bottle and, mimicking Hagiwara Kenji's tone, laughed, "I can't be sure, but this might be a possibility. We've already analyzed it; Mr. Yokoyama alone couldn't have burned it so quickly."

In Chernobog, Mephistopheles used ketones as an accelerant. Akihara had previously suspected gasoline because of the strong smell of it at the scene, but considering the environmental factors—it was a parking lot, so the smell of gasoline was perfectly normal—he then recalled the storage room he had briefly glanced at earlier.

"Whether it is or not, we'll find out by asking the old cleaning gentleman who accused me," Akihara concluded. "At least he should know whether it's his or not."

……

"What? Anhydrous ethanol? Don't use those technical terms, what is that?" The old cleaning man on the other end of the phone had been released after leaving his home phone number, and he was completely confused after hearing the police's questions.

When Date Wataru, who was making the call, turned to look at Akihara, Akihara smiled slightly and shrugged in response.

"It was a white plastic bottle containing anhydrous ethanol—well, to put it simply, high-concentration alcohol. We found it on a flatbed cart in the storeroom, do you remember?" Ida Kou turned his head and patiently explained to the person on the other end of the phone.

The old man on the other end of the phone began to fum indignantly: "What kind of nonsense is this 'anhydrous ethanol'... Alcohol is alcohol, why make it sound so high-tech?... And are you questioning my memory? There's absolutely no such thing before! Let me tell you, I was known for my sharp mind back in school..."

Date Wataru quickly covered the microphone, looked up at everyone, and finally said to Akihara, "Your guess might be correct."

At that moment, a policeman rushed over from outside the parking lot, jogged up to the head of the First Investigation Division, and reported something in a low voice.

The group exchanged glances and moved closer to the section chief, leaving Ida Wataru alone to quietly comfort the old cleaning man who was speaking eloquently on the other end of the phone.

“We visited nearby shops and checked their surveillance footage…” The police officer took out several color-printed A4 sheets of paper with blurry surveillance screenshots on them. He pointed to one of them and showed it to his section chief. “That’s him. We first spotted him at this intersection, before he was carrying that plastic bag.”

Then he flipped to the next page. "Next is this intersection, and there's nothing there either."

This time, he showed a screenshot from a video recording inside the store. "This is a pharmacy. Through our questioning, the owner said he remembered it, and his description basically matched the victim's characteristics."

"He said that the victim bought anhydrous ethanol from his store. Initially, he wanted to buy disinfectant alcohol, but his store happened to be out of disinfectant alcohol. So he suggested that the victim buy anhydrous ethanol, which could be used as disinfectant alcohol after dilution."

He also attached a photo of other anhydrous ethanol displayed on a shelf in a pharmacy, which was exactly the same as the one that Akihara Kazumitsu had found.

"In conclusion, we believe that the white opaque plastic bag the victim was carrying contained anhydrous ethanol, but the bottle was not found at the crime scene. The next step of the investigation will focus on finding the missing anhydrous ethanol."

Matsuda Jinpei raised his hand slightly. "Ah, if that's it, we've found it. It's on the flatbed cart in the storage room."

The policeman, holding up several pieces of paper, momentarily forgot what to do, and stared at Matsuda Jinpei for a few seconds without saying a word.

Kenji Hagiwara coughed lightly, smoothly smoothing things over. "Although they look very similar, to confirm that they were indeed purchased by the victim, we need the help of the senior experts in the forensic department. Thank you for your help." With that, he took the white plastic bottle from Kazuhiro Akihara and handed it to the policeman.

The policeman put on his gloves, took out an evidence bag, carefully took the plastic bottle, and nodded to them.

"But more importantly, do you have any specific information about the smoke detectors used in this shopping mall?" Matsuda Jinpei was completely uninterested in the atmosphere.

Fortunately, the policeman didn't hold it against him and nodded to Matsuda Jinpei. "Wait a moment, I'll go ask the supermarket manager."

"Please," Matsuda Jinpei said, bowing.

After finally calming the old man down, Date Hang hung up the phone, feeling his smile was a little stiff. He walked back to the three of them and asked, "How did it go?"

Kenji Hagiwara briefly explained the current situation to Wataru Date, then continued, "It's now certain that anhydrous ethanol is inextricably linked to this case. The next question is the method. If anhydrous ethanol is an accelerant, and if there is a perpetrator, how exactly did they ignite the victim?"

Matsuda Jinpei nodded. "Actually, I've had a guess since just now, but I need more evidence to prove it. It all depends on the results of that senior's inquiry."

A short while later, the same policeman returned with a thin booklet in his hand, looking somewhat annoyed. "The person in charge stammered and dodged questions when asked about technical details, but at least he managed to find the instruction manual for the smoke detector extinguisher. Take a look."

Matsuda Jinpei politely thanked him and accepted the book, briefly flipping through it.

"This smoke detector fire extinguisher is designed to spray for at least 30 minutes, generally up to 1 hour... If smoke or high temperature is detected after the time is up, it can continue to spray..."

"Smoke detectors are connected to fire water tanks, making it easy to replace the liquid in the tanks..."

When he looked up again, his eyes were full of confidence. "I think I know the criminal's modus operandi."