Twin Prison Locked Room Murder Case

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* Junji Kaji

The **Twin Prison Locked Room Murder Case** is a murder case that occurred in the Moon Prison almost seven years ago.

It is the 17th main case in the *Ron Kamonohashi: Deranged Detective* series.

## Overview

Seven years ago, Juntaro Mihane purchased the Moon Prison with his inheritance. He was a member of a religious organization whose goal is to connect and communicate with outer space and he shut himself in the prison "to connect with space." The designer of the Two Prisons, Jarr Jorr, had also been part of this organization and built the prisons to achieve its goal.

Not long after the purchase, Juntaro was killed with a hit on the head. His family filed a missing person report, but he was not found and eventually declared dead. His corpse was found seven years later in the Moon Prison by his family.

Two weeks before the corpse's discovery, Juntaro's wife Youko Mihane, his son Kiyotaka, his brother Junji Kaji, and his servant Kaki Sakanoue went to the Moon Prison because they wanted to liquidate Juntaro's estate. Because the door was locked and they did not want to damage the prison's sole and unique window, Kiyotaka contacted the Sun Prison's owner and asked them if he could borrow the Sun Prison key to unlock the Moon Prison. The Moon Prison key was damaged in a house fire seven years ago, shortly after Juntaro was reported missing. As the two prisons are twin buildings, their keys are identically shaped and, thus, the Moon Prison can be unlocked with the Sun Prison key as well. The Sun Prison's owner agreed, and the key arrived two weeks later. Juntaro's family opened the Moon Prison and found his corpse lying inside. Curiously, when they were there weeks earlier, they had not seen Juntaro's corpse through the window.

The door was locked and is made of thick steel, leaving not even enough space for a string to pass through. The floor is made of a single slate of concrete, making it impossible to dig a way into the building, and the chimney is too narrow for a human, adult or child, to enter. For these reasons, it is a perfect locked room mystery.

Seventy years ago, a locked-room murder also occurred at the Sun Prison. It is still unsolved.

### Further murders

The next day, Kaji's corpse is found in the Moon Prison. His murder mirrors the Sun Prison Murder: He has been tied to a chair and stabbed to death. He was stabbed after he was tied to the chair, and the prison door was sealed from inside with a brass bar. After a thorough inspection, Fin declares that Kaji's murder is also a perfect locked room case.

## History

After Ron informs Totomaru about an article by Chicory about the discovery of a seven-year-old corpse in the Okutama Mountains, they drive there. On the way to the Moon Prison, Ron tells Totomaru that the prison is one of the "Two Prisons" an eccentric architect built one hundred years ago. The other prison, the Sun Prison, is located in England. Seventy years ago, someone was murdered there too, though this locked-room murder has never been solved.

They meet Amamiya at the Moon Prison. She allows them to help with the case and briefs them about it: Juntaro Mihane locked himself in Moon Prison "to connect with space" seven years ago, right after buying the prison. Shortly afterward, he was murdered. He had first been reported missing before he was declared dead; his corpse was only found today by his family. Amamiya also introduces Juntaro's family to Toto and Ron: His wife Youko, his son Kiyotaka, his younger brother Junji Kaji, and his servant Kaki Sakanoue who are being questioned by an officer. They have been at the Moon Prison two weeks earlier as well. However, they did not see Juntaro's corpse then.

Toto and Ron take a look through the prison's only window. Through it, they can look into the prison's single room—and right at Juntaro's corpse lying on the ground. Toto notes that Juntaro's family could not have possibly overlooked the body, and Kiyotaka shows him a picture he took through the window as proof. Indeed, two weeks ago, Juntaro's corpse was not in the locked prison.

Amamiya leads Ron and Totomaru inside to show them that it is a perfect locked-room mystery: It is seemingly impossible for someone to have killed Juntaro and let his corpse disappear and reappear in this "sealed" prison. After they leave the prison, an officer approaches them to say that he believes the family is lying to "deify" the Moon Prison as "locked rooms" and "impossible crimes" do not exist outside of fiction; it is likely that Juntaro simply fell on his head by accident and died.

When Amamiya remarks that it would indeed be nice if this was only an accident, Shachi appears to tell her that she does not have the authority to declare Juntaro's death an accident. His hooded companion then approaches Toto, Ron, Amamiya, and the officer and says that she will assume direction of the crime scene before she shows them her S-rank detective license and uncloaks herself. Amamiya and Ron respectively recognize her as the world's expert on locked room studies and BLUE's locked room instructor, Fin Fennec.

Afterward, Amamiya briefs Fin about the case and gives her the Moon and Sun key to examine; Ron and Toto watch them from afar. Only by touching the keys, Fin confirms that they are the genuine items which amazes Amamiya and Toto. Ron tells him that all instructors at BLUE are geniuses and experts in their respective fields. He also reminds him that, like Mylo told him, a BLUE instructor suddenly appeared before him and adds that they need to be careful around Fin as she may be the M. Family spy.

Amamiya invites Fin to touch the inside of the prison as well and offers her help if she needs it. Fin thanks her and excuses herself to talk to Ron and Totomaru. Before she reaches them, Shachi appears and loudly asks Ron what he is doing at the crime scene. Ron covers his mouth with his hand and tells him to call him "Kamoo" before he asks who Shachi is. Shachi introduces himself as Fin's bodyguard and reminds Ron that they went to BLUE together. Ron vaguely remembers him. Then, Fin joins them.

Ron greets her and reminisces how they used to compete in her class: She would bring her students unsolved locked-room mysteries to solve. He only managed to solve three while she could solve eight. Fin admits that she solved those three cases beforehand; she had lied about the cases' unsolved status. Still, for old time's sake, Ron suggests that Totomaru will compete with her to solve the Moon Prison's mystery, but she is uninterested. She informs him that she has heard of the rumor about him and illegal investigations and states that she will punish him without hesitation if she sees a sign of the rumor being true.

Fin then changes her mind about the competition and accepts it. Because Toto already examined the prison and questioned the family, Fin goes to scrutinize the Moon Prison. With her Phoenix touch, she inspects its door (3cm thick, made of iron, no signs of tampering) and walls (made of bricks imported from England, three-layered), and Shachi helps her to reach and touch the ceiling (no cracks, no hollows, no signs of restoration) as well. She notices no irregularity until she touches the ash in the fireplace and finds foamed styrol mixed with it. Fin concludes that something was applied in the fireplace and solves the mystery to Ron's and Toto's surprise and amazement.

Fin then gathers everyone to tell them what happened: The culprit never entered the prison in the last seven years—and neither did the corpse. Juntaro's body was in the prison for all these years, hidden behind a dummy wall made of foamed styrol. The block were likely connected via a cord which was threaded through the chimney; its end was stuck out of it and fixed to ensure that it did not slip back inside. The culprit never wanted anyone to discover Juntaro, but when they learned his family asked for the Sun Prison key to be delivered to Japan, they went to the Moon Prison and pulled on the string, lifting the blocks through the chimney and removing the dummy wall. This is the reason why Fin found pieces of foamed styrol in the fireplace. She also suspects that the dummy wall held some kind of clue that pointed back to the murderer.

She deduced that there must have been a dummy wall because, in the photo Kiyotaka took, the sunlight is striking a larger area of the wall than it does now although Kiyotaka's and her picture were taken around the same time, from the same location, and with the sun at the same height. Therefore, two weeks ago, the wall was closer to the window than it was now.

The murderer can, thus, only be someone who knew the Sun Prison key was being delivered to Japan. However, Fin does not reveal the culprit as her only goal was to solve the locked room's mystery; she leaves the rest to the Metro Police and returns with Shachi to the guesthouse where they have been staying, the Moon Lodge. Ron is upset that Fin solved the mystery before him and drowns his sorrow in brown sugar syrup. Afterward, he and Totomaru check into the Moon Lodge as well.

The next day, Ron tells Toto about the murder at the Sun Prison. Then, Amamiya calls Toto to inform him another corpse has been discovered in the Moon Prison: Junji Kaji has been tied to a chair and stabbed to death, just like the Sun Prison victim had been many years before.

Toto and Ron head to the Moon Prison; because Amamiya is not here yet, Toto has been put in charge of the crime scene. Fin and Shachi arrived only a moment earlier. She informs Totomaru that she made sure that nobody entered the prison and that they confirmed Kaji's death by considering his dilated pupils through the window and taking his temperature via thermography. She adds that, judging by the pool of blood, Kaji was likely stabbed after he was tied to the chair. This means that the culprit was with him the room. However, like in the case at the Sun Prison seventy years ago, a brass bar has been mounted to the inside of the door, making it impossible to open and sealing the room from within.

Everyone then helps to thoroughly check the outside of the prison to find proof whether someone entered or exited the building. During the examination, Fin approaches Ron to remind him that she is watching him. According to BLUE's operating regulations, "any activity intended to clarify the truth" is classified as detective work; Fin will decide if Ron "observing" the crime scene falls under this or not.

Afterward, they conclude the examination, and Fin declares the case a perfect locked room right before Kiyotaka, Youko, and Sakanoue arrive.

Kiyotaka wants to see his uncle's body, but Toto denies him the access. He also testifies that Kaji was fixated on finding Juntaro's killer; Kiyotaka had tried to talk him out of it, but he did not want to listen. Youko adds that Kaji was furious about Juntaro's estate allocation because Juntaro left him nothing. Kaji wanted to find evidence that would prove Kiyotaka as his father's killer so that he would get the money. This makes Toto believe that Kaji came to Moon Prison to search for evidence, but neither Kiyotaka, Youko, nor Sakanoue say anything about this.

Totomaru then asks Youko if they could break the window, and she agrees. The window is broken and everyone can now enter the prison. Kaji is examined and no drugs are found in his system; this indicates that he was indeed killed inside the prison. Fin and Shachi then scrutinize the room, but except for the brass bar, everything is the same as yesterday.

Fin wants to check the bar for magnetism, but Shachi has forgotten the compass. Ron offers her his, and she asks him why he, a sweetsmonger, is carrying a compass. Before he can answer though, Sakanoue yells through the window at Ron, Fin, Shachi, and Toto, saying that it is their fault that Kaji died because they did not arrest the culprit yesterday. Toto wholeheartedly apologizes to her; they only focused on solving the mystery, not apprehending the culprit, and now, another life was lost and will never come back.

His words open Fin's eyes to her own arrogance and she thanks him for this and says that she will catch the culprit to atone for her shame. She then tells Ron that, according to her father's words, someone is only a detective if they solve the mystery; otherwise, they are only a bystander. Thus, as long as she is the one who solves this case, Ron cannot be considered a detective and can stay and help with the investigation, but only for this case. Ron notes that while it is generous, this means that Fin will be too focused on the case to bother with him.

While Fin takes Ron's compass to check the brass bar and learns that it is not magnetic, Ron declares that he will solve the case "his" way then.

Afterward, Fin and Toto gather Youko, Kiyotaka, and Sakanoue to question them. Fin apologizes for still not having apprehended the culprit and informs them that the current case is a replica of a seventy-year-old case from England. Kiyotaka immediately realizes that she means the Sun Prison Murder Case and says that Kaji found out about that case when he researched the Moon Prison following Juntaro's disappearance.

Toto says that, just like seventy years ago, the prison door was sealed with a brass bar from inside. It is possible that it was stored somewhere until now because of its good condition and asks Sakanoue, Kiyotaka, and Youko whether they have any ideas about that. When Youko ponders what to say, Kiyotaka yells at her that she is a coward and Sakanoue becoming senile; because of that, Kaji pushed everyone around and did what he wanted. Kiyotaka then reveals that the bar was stored in the shed at their home. Hearing this, Fin tells them they are all suspects as they all had access to the bar. Youko starts to panic at her words and sinks shaking to the ground; Sakanoue tends to her.

Fin, Toto, Ron, and Shachi then talk about how they will proceed. Fin and Shachi will go to the shed with Kiyotaka while Ron wants to stay behind to search the prison again because Fin only confirmed that nothing is there physically speaking. When she hears this, she remarks that one of her students said that once, and Ron tells her that was him. Fin also addresses the Bloody Field Trip Case; she has concerns about it as it was a locked room case. However, before she can talk further about this, an officer informs her that the car going to the Mihane estate is ready. She and Shachi then leave.

Meanwhile, Totomaru and Ron talk to Youko who is feeling better again. Ron allows her to have some of his homemade brown sugar sweets, and Youko confides them that Sakanoue has become sticky-fingered when it comes to her treats. She also gone a bit senile, but she will not fire her because her late mother hired her and paid her in advance for the next ten years. Futhermore, Sakanoue can still decently cook, so firing her would be a waste; Kiyotaka does not like her cooking though because of the abundance of vegetables. Youko also admits that she wished they had never opened the Moon Prison. Then, it would have been like nothing happened. If the others had been on her side, she could have lived in peace.

Hearing this, Ron thinks about the prison door and the brass bar and solves the case and realizes that there is a reason why Fin could not solve it. However, the method behind the murder cannot be the same one used seventy years ago. Thus, the cases are not connected, and the Moon Prison Murder Case is only a copycat crime. He then asks Sakanoue who has made a cooking mistake lately if Kiyotaka cooks for himself. Sakanoue replies that she has not made a mistake in thirty years. Totomaru scolds Ron for making her angry and Ron tells him that "guilty people make people guilty."

A moment later, Fin and Shachi return, and Fin says that there were no clues in the shed and they have to start anew. Ron then announces that he has solved the case, and Fin stares at him.

Amamiya, Fin, Shachi, Kiyotaka, Youko, and Sakanoue gather in front of the Moon Prison to hear Toto recite Ron's deduction concerning Kaji's murder: Fin did not find anything in the prison because the culprit knew about her Phoenix touch ability and found a way to destroy a clue's material properties. The clue was a powerful neodymium magnet. The murderer inserted it into the brass bar and concealed it with a brass cover which they polished to get rid of any evidence that the bar had been tampererd with. They attached the magnet to the door, a bit above the bar bracket, and then left the room. Afterward, they used a blowtorch to heat the door and the bar until the bar was heated to 330 degrees—neodymium's Curie temperature, the point that has to be reached for the material to lose its magnetism. The bar then dropped into the brackets and locked the door.

Because the culprit used a blowtorch they were not familiar with, they hurt their left hand—and Sakanoue has been suspiciously covering her left hand. Until yesterday, when she clutched her hands, her right hand had been on top, not it was her left one. Sakanoue claims that she burned her hand when a pot boiled over, but Youko points out she said she never made a cooking mistake in thirty years. Sakanoue then replies that she has no motive to kill Juntaro and Kaji.

Amamiya says she cannot see a motive, but Ron can: Sakanoue was trying to protect Youko. She cooks meals with many vegetables and hides her treats because she worries about her mistress' fragile health. Youko defends Sakanoue, saying that she would never considers that. Then, Sakanoue confesses. Totomaru points out that she only looked out for Youko though, not Kiyotaka because she does not care about what he eats, and asks why.

Sakanoue tells everyone that she promised Youko's mother to protect her daughter. Youko's mother did not like Juntaro as she realized he would only bring trouble, and because Sakanoue felt indebted to her mistress as she saved her life when she was young, she agreed to take care of Youko. Juntaro had been squandering the Mihane fortune for his religious group, and Kaji had tried to pin his brother's murder on Youko and Kiyotaka to get his hands on the fortune. Sakanoue had to kill them to protect Youko and the fortune; she imitated the Sun Prison Murder Case because she hoped if she copied an unsolved murder, her murder would never be solved too. She also learned about Curie temperature on television and created the bar in case she ever needed it.

And although she was caught, Sakanoue is happy because she could fulfill her promise to protect Youko. She will die soon anyway; with her promise fulfilled, she can face her first mistress in heaven. Youko remarks that Sakanoue must have really gone senile but Kiyotaka replies this is not just senility.

Later, Fin tells Totomaru that he solved the case well. He thanks her and adds that he has no evidence to prove there was a magnet in the bar though. Fin replies that he does not have to worry about this: She and Shachi took an x-ray of the bar and confirmed the magnet's presence inside it because Fin had actually solved the case before Ron did. Then, Shachi and Fin set out to leave. Ron wants to talk to them but because of his medication to counteract Kill on Sight, he faints before he can though.

A few days later, Ron and Toto head to the airport where Shachi and Fin are waiting for their flight home. Ron tells Fin he solved the Sun Prison Murder Case. She remarks it is a convincing solution; if they were at BLUE, she would give him 90% for it. However, because he has no physical evidence, it cannot be accepted as an official solution.

Fin then recites one of her father's sayings: "There's no sin in a heart that seeks the truth." Because he risked his life to get involved in a case in front of a BLUE instructor and even followed her to the airport, Fin knows that Ron not solely did all that just to solve the case. He wants something else, and she is willing to hear him out.

Ron tells Fin that he is gathering information about the Bloody Field Trip Case and asks why she is also interested in that case. Fin is interested in it for two reasons: First because it is a locked room case as only Ron could enter or leave the crime scene. Second because of Emmerich's unusuals actions. Last years, Fin was running an errand close to the Bloody Field Trip crime scene and decided to stop by. She saw Emmerich entering the hideout and noticed someone trailing after the principal: It was Dr. Hirsch, the anatomy instructor. She confronted him about his presence, and he claimed he wanted to check if he had not left anything at a crime scene he had worked on. When he saw Emmerich, he was surprised and stuck around without calling out to her. According to Fin, she checked the documents and learned that Hirsch had nothing to do with the Bloody Field Trip though as he was not in England at that time. That is everything Fin knows. She adds that this changes nothing and that the case is settled. Then, she and Shachi leave to get to their plane.

Ron and Toto return to the Maison du Kamonohashi. There, Toto asks Ron why he did not inform Fin about the unidentified blood because she could be of help. Ron replies they cannot rule out that Fin is the M. Family spy, though he hopes she is not. Toto also says he did not have the feeling that she is the informant. Ron then says that another "fascinating individual" connected to the case has appeared: Dr. Hirsch who almost killed Ron once. Ron would not put anything past him and declares that Hirsch would be a "formidable opponent."

Meanwhile, in England, Hirsch is dissecting a corpse.

## References

1. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, page 7
2. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, pages 8-9
3. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, pages 6-7
4. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, pages 2-3
5. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, pages 9-12
6. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, pages 13-14
7. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, pages 3-4
8. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 53, pages 18-19
9. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 54, page 5
10. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 54, page 8
11. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 51, pages 2-19
12. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 52, pages 1-18
13. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 53, pages 2-19
14. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 54, pages 2-19
15. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 55, pages 1-18
16. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 56, pages 2-21
17. ↑ *Ron Kamonohashi: Deranged Detective* manga; Chapter 57, pages 2-12