All the officers went in and started searching the spa, but in the end they found nothing that could be connected to the murder case from 2 years ago, not that this wasn't foreseeable. 

Having found nothing of note, they had to leave, leaving only Agent Sato and Takagi, as well as Shikami who was analyzing the information he had obtained about everything that had happened. 

Suddenly Shikami's phone rang, and it turned out that it was Inspector Megure who wanted to inform him of the investigation done on the former employees of the spa. 

"Shikami, all the former employees said that there was always humidity in one area of ​​the spa, and they usually always had to renovate the walls for this reason"

"I understand, thanks for the information Inspector Megure!" Shikami said with a touch of clarity

He finally found a lead to solve the case, but first he had to make sure his new lead was correct. Going to the manager, he asked him "show me the whole map of the entire spa structure"

To which the Manager was surprised and then took a step back and went to get his computer again to show him the mapping of the spa facility's structure. 

Shikami who received the computer, I start checking the image. A minute passed and he finally managed to find the tool to kill the twenty people. 

I called Agent Sato who was talking to an employee to get some useful information, and then told him "can you call some agents to get the killer of the Sauna case, because I solved it!"

Hearing his confident words, everyone was surprised. Officer Sato nodded and gave orders on his walkie talkie "to the officers near the spa, request immediate backup!"

Finishing giving orders, he looked at Shikami curiously and asked "who is the killer, and how did he manage to kill more than 20 people without even using a gun or knife?"

Shikami told him "from the dossier on the twenty people, it was understood that they died because they were trapped inside the Sauna, thus cooking them with steam but no one knew why there was so much steam to cook them alive. 

So the only possibility was that the staff did it, but none of them are the real killer, because only the manager who could control the machine to extract the steam or hot air from the sauna which was used for emergencies, could commit murder, right mister manager"

Turning to square the manager who had become nervous, I continue his speech to clarify the functioning of the assassin "of all the saunas in Beika City, only this one has a machine that sucks in the hot steam, and this is very strange, because it is not one thing is necessarytype. 

Usually you open the door directly and thus recover from the heat of the sauna, but by having a tool that sucks the air, it is easier to remove the excess heat from the sauna rooms. 

Too bad the manager had it installed badly, isn't it? " she asked looking into his eyes

The manager who started to worry, innocently said "Mr. Policeman, it's true that I installed air extraction for each sauna cabin, but I did it for the safety of my customers, because this way it is easier to enjoy a safe and comfortable sauna. 

But now he accuses me that I set my instruments wrong, and this is not true, why is he accusing me? "

Seeing that he seemed innocent, Shikami clearly explained to him: "It is true that the equipment of the air extractor seemed to be placed in the right way, but from the mapping of the structure, a big problem can clearly be seen. 

And this is the structure's system to circulate the air in each sauna cabin. The air it sucks in has to be thrown out somewhere, and where do you think that air went on that day two years ago, until you fixed the air duct? "

The manager trembled and then looked at him with shocked eyes, asked "w-how do you know so much?!!"

"simply because I discovered various clues as to who was responsible for the massacre of the twenty people, but it is more correct to say that it was an accident, isn't it, Mr. manager" Shikami said to the surprise of everyone who was listening

The manager sighed and admitted his faults: "Yes, it's true, it's because of my haste and stupidity at the time that the twenty people died. 

Three years ago I had to attract new customers, because our spa was not having success, so I searched the internet to see if I could find something that could attract more customers, and on a web page I found the answer. 

I just had to renovate my sauna cabin, so I bought the air extractor which was finally connected into the air duct I created in a hurry, and so I managed to complete the renovation within a year. 

Then came the twenty customers who entered their cabin, unaware that they would die because of me, just because I built an air duct without consulting an expert or having permission. 

So when they turned on the hot air intake, the situation started to escalate, because the hot air was only going into the other cabins, thus creating a vicious circle. 

If only this had been the problem, it would have been easy to escape death, because the customer could leave the cabin, but something unexpected happened. 

The system that controlled the air intake went out of control due to the continuous circulation of air that increased, thus accumulating heat and making the rooms hotter and more toxic, because the materials were harmful. 

At that time I didn't know that the seller would sell materials that were harmful and therefore lethal to humans, and that's why when the hot air reached a certain degree, he made sure to release that toxic part of the air duct materials , thus making salads for those twenty people. 

They couldn't get out in time, because by now they had inhaled a lot of it and so they immediately passed out. Not knowing what to do, I just pretended not to know anything, but remorse wouldn't let me sleep and so I unconsciously kept the evidence

And at the beginning of our talk, when I asked you why you were so calm, you said: I am confident that none of my employees committed murder "

Officer Sato approached the manager and said "you will be arrested for murder of twenty people, illegal renovation with harmful materials..." As he spoke, Shikami looked at the Manager

Then he said "it's not true that you felt guilty, because nothing that was on the computer proved it, much less the fact that you seemed relaxed and carefree. 

I really think you hid the key clues in the Sauna case, and not that air duct map that looked suspicious"

Hearing his words, the manager laughed and said mockingly "if I had come two years earlier, maybe there would have been someone who could have caught me, but there was only that incompetent Detective Mouri!"

As he was taken away, he laughed with joy thus showing his true personality. Agent Sato and Takagi didn't understand the gist of their conversation, so Shikami explained "the Manager did it on purpose to buy that toxic material and the air suction tool, and just to get noticed and face a Detective capable that could give him a stimulus. 

So in the end he turned out to be just a psychopath who wanted the attention of the cops, detectives, and ultimately the public."

So solving a case both simple, because the evidence was on the manager's computer, but also difficult because he was very intelligent, in the end he decided to get arrested for some reason. 

Inspector Megure called the mysterious man and told him the outcome of the case, so Akiro's father handed himself over to the police and they gave him 5 years in prison, because he only made a verbal threat. 

It was eventually revealed that he had no bomb. 

End of Episode 37