Who is the murderer of Mask Hotel?

The four murderers of the Masked Hotel are Katagiri, the husband who killed his wife to defraud the insurance money, the deceased's student, and Nagakura Maki.

The story of "Masked Hotel" begins with a series of codes left at the scenes of three consecutive murders in Tokyo. The investigation headquarters analyzed the codes of these three incidents and deduced that the fourth murder will be Takes place in "Tokyo Hotel Cortesia". In order to prevent the fourth incident from happening, several investigators were placed in the hotel to conduct search operations as waiters.

A blind female guest Katagiri first aroused Nitta’s suspicion. Judging from various details, she should be a normal person. After checking out, Katagiri proactively admitted that he was not blind. She came here to check in for her blind husband. Now she is very satisfied with the hotel's service and will let her husband stay with confidence. With this reason, Nitta's suspicion can be dispelled.

A woman named Anno stayed in the hotel. She took a photo and called the person in the photo a stalker. Please inform the front desk if you see this person. When the "stalker" in the photo came to the hotel, Shang Mei found that the gentleman named Guan Lin was very well-educated and did not ask about other guests after checking in. Out of all the reasons for serving the guests, Naomi went to Anno's room and reminded her not to go near the room where Tatebayashi was.

After a while, Shangmei realized how the victim could have photos of the stalker. Perhaps Anno was the stalker and she had made a fatal mistake. Sure enough, hotel surveillance showed Anno heading to Tatebayashi's room. Shangmei and Nitta hurried over. Fortunately, Anye, who came to catch the adulterer, only brought out a divorce agreement.

An Ye is not the murderer, but this incident also made Shang Mei realize a problem. Hotel employees often make guests resentful, and maybe the murderer's target is a certain employee. However, this thought was fleeting and Shangmei did not mention it to Nitta.

Nitta once investigated the first murder case. He initially suspected that the deceased Okabe had embezzled public funds, but was silenced by his accomplice Masaki. At the time of the incident, Masaki's ex-girlfriend Chizuru called Masaki's home phone, which was confirmed by Chizuru's best friend Inoue. Since Masaki's home was an hour away from the crime scene, Masaki was ruled out as a suspect.

But due to female intuition, Shangmei does not think that her ex-girlfriend will call her ex-boyfriend unless someone instigates her. In addition, inspired by the hotel's program-controlled telephone, Arata believed that Inoue secretly changed the number stored in Chizuru's mobile phone. The call that night should have been to the landline near the murder, not Masaki's house.

Masaki and Inoue were quickly arrested. After investigation, it was found that Inoue had an extramarital affair with the victim Okabe, and he cooperated with Masaki to kill because of emotional entanglements. But the matter was not over. The police recovered deleted emails from Masaki's computer, confirming that he conspired with three other people to commit a series of murders. They committed crimes for their own purposes and misled the police by pretending to be serial murders. After this layer of disguise is lifted, it is only a matter of time before the first three cases are solved. Only the fourth case remains a mystery.

Staff from various departments are more cautious, waiting for the murderer to appear. A gift was delivered to the front desk, designated for the groom, Miss Alpine, who was preparing to hold a wedding at the hotel. Nitta noticed that the gift was wrapped in department store wrapping paper, but it was not sent from the department store. After inspection, it was found that there was an unobvious pinhole in the bottle stopper, and highly toxic ingredients were indeed detected in the gift red wine.

The police immediately turned their attention to protecting Miss Gao Shan and her fiancé, and deployed manpower at the wedding to increase security. It's just that Nitta, who contributed the most, was unable to participate in the action and still had to stay at the front desk.

At the wedding scene the next day, a suspect was successfully captured and an envelope was found from his pocket, which contained a note with a number on it. But the suspect claimed that he only accepted the commission from the Internet to deliver the letter.

At this time, another police officer discovered a suspected case. The deceased, Matsuoka, was a drama actor who had stayed at the Cortesia Hotel. He had needle holes in his ankles and the cause of death was unknown. Nitta saw the poster that was sent and was immediately shocked. This drama poster features not only Matsuoka but also Katagiri. Nitta understood and fell into the trap of swaying the tiger away from the mountain.

At this time, Katagiri checked into the hotel again, named Naomi and led her to the room. Nitta rushed over and saw Katagiri holding a syringe and stabbing Naomi's neck. Arata pulls Katagiri away with force and saves Naomi.

It turns out that a year ago, the ruthless boyfriend Matsuoka checked into the hotel. Katagiri, who was pregnant at the time, went to the hotel and asked for the room number, but Naomi at the front desk declined. Katagiri, who waited outside the hotel all night, was so cold and tired that he miscarried.

Therefore, she killed Song Dao and asked Shang Mei to bury her child with her.

In the second case, the husband who killed his wife to defraud insurance money was arrested; in the third case, the student of the deceased surrendered to the police. The fourth note pointed to the location of the first case, a cycle that also heralded the solving of all cases.