The Decagon House Murders

by Yukito Ayatsuji

  […] Subsequent investigations have led to the discovery of a further body: that of a man who met with an unnatural death in a room beneath the Decagon House.

  The remains are partly skeletal, with time of death estimated at four to six months ago. Age at death is estimated at mid-forties. Wounds suggest the man was beaten on the head.

  The existence of the underground room was discovered after the fire. It has been suggested that the body is that of the missing gardener, Yoshikawa Sei’ichi (46), who disappeared after the incident on the island in September of last year. Efforts to identify […]

  TWELVE

  The Eighth Day

  1

  The large campus of K— University cuts through the side of a mountain and spreads out extensively in a peculiar shape. In one corner of the campus stands the Box, a two-floor reinforced concrete building housing the circles and clubs officially sanctioned by the university. It was the second day after the six bodies had been discovered on Tsunojima. On the afternoon of Wednesday, 2nd April, ten or so members assembled in the Mystery Club’s room on the first floor.

  Two conference tables had been crammed into the disorderly room. The students sat around them, packed close together. Among them was also ex-member Kawaminami. Shimada Kiyoshi, the younger brother of the inspector in charge of the investigation, was not present.

  Maybe he is trying to be considerate. Or maybe he has something else to attend to?

  Morisu Kyōichi felt slightly anxious, but quickly got over it.

  It doesn’t matter, he knows nothing. He hasn’t noticed anything and won’t, either.

  Inspector Shimada arrived with two officers, slightly later than scheduled.

  He frowned at the smell of cigarettes lingering in the room, recognized Morisu and Kawaminami and greeted them heartily. Then he turned to the whole group.

  “I appreciate you all coming here today. My name is Shimada.”

  After a formal introduction, he sat down in the seat reserved for him.

  After all the club members had introduced themselves, the inspector explained the outline of the incident. He then moved in a leisurely manner to the main issue, periodically looking up from the notebook in his hands to the faces of the students.

  “I’ll repeat the names of the six who died on Tsunojima once more. Yamasaki Yoshifumi, Suzuki Tetsurō, Matsu’ura Junya, Iwasaki Yōko, Ōno Yumi and Higashi Hajime. I am sure you all knew them well.”

  The faces of the six appeared in order in Morisu’s mind as he listened to the inspector.

  Poe, Carr, Ellery, Agatha, Orczy and Leroux.

  “Of these six, five are thought to have already died by the time the fire broke out. Ōno and Higashi were strangled and beaten to death respectively. Yamasaki, Suzuki and Iwasaki were very likely poisoned. The last person, Matsu’ura, was still alive when the fire broke out. It appears he had doused the room and himself in kerosene and committed suicide.”

  “So Matsu’ura murdered the other five and then committed suicide?” asked one of the members.

  “That’s what appears to have happened. As for how he would have obtained the poison thought to have been used on the three victims: Matsu’ura’s relatives own a big pharmacy in O— City and he often visited them. So that would explain it. We are working on that assumption for the moment.

  “But we have been unable to find a motive. That is why I asked you to come here today. I hope you’ll be able to help me.”

  “Could it have been someone else?”

  “Very unlikely.”

  Morisu almost sighed with relief on hearing the inspector’s answer.

  “First of all, everything points to Matsu’ura Junya having committed suicide. Furthermore, the five others were murdered in different ways at different times. One of them had died more than three days earlier and each of them died under different circumstances. They say that even fishing boats rarely go out to the sea around Tsunojima, and I think it highly unlikely someone would have taken a boat to the island to commit a massacre lasting several days.”

  “But Inspector,” interrupted Kawaminami. “Nakamura Seiji is thought to have been murdered and burnt to death under similar circumstances in the incident in the Blue Mansion last year.”

  “Well, there are all kinds of strange circumstances tied up with that case.” The inspector shot him a sharp glance. “At the time, the disappearance of the gardener caused us to suspect that Nakamura Seiji had been murdered. One person who should have been on the island wasn’t there, so suspicion naturally fell on that person. We assumed he was the murderer.

  “But now we have found a secret underground room beneath the burnt-down Decagon House with the body of a murdered man inside. I think it was in yesterday’s newspaper. Based on the time of death, age and physique, we suspect it’s the body of the gardener.”

  “Aha, I understand.”

  “So we were forced to change our assumptions about the Tsunojima incident. We now suspect that Nakamura Seiji’s death was a suicide by burning and that the whole tragedy was a murder–suicide carried out by him.”

  The inspector gave Morisu and Kawaminami a meaningful look.

  “We got hold of some new facts that support this theory from a certain source.”

  Shimada Kiyoshi must have talked, thought Morisu.

  But he had clearly stated he had no intention of passing any of the facts he knew, or the suspicions he had, on to the police. Morisu had believed him when he’d said that. Even if Shimada’s own brother was a police officer. But that would mean that…

  Was it Nakamura Kōjirō who had talked?

  “But anyway.” Inspector Shimada looked at everyone in the room. “How many of you knew those six were going to the island?”

  Morisu and Kawaminami raised their hands.

  “Hmm, just the two of you. Do you know who came up with the plan to go to the island in the first place?”

  “They had been talking about it for a while,” answered Morisu. “And then, thanks to some connections, they managed to make the necessary arrangements.”

  “Connections, you say?”

  “Yes. My uncle—his name is Tatsumi—is an agent handling a large variety of properties. He bought the Decagon House from the previous owner. So I told them I could ask my uncle.”

  “Oh. Tatsumi Masa’aki, eh? So you’re the nephew he was talking about. But you didn’t want to go to the island yourself?”

  “No. I didn’t feel like going to a place where such a horrible tragedy had occurred just six months earlier. They all seemed happy about the trip, but I thought it distasteful. And then there was the problem of the number of rooms.”

  “Number of rooms? But there were seven guest rooms?”

  “Practically speaking, there were only six rooms. You can ask my uncle, but one of the rooms was not in a usable state. Rainwater had ruined it completely.”

  There was nothing in that room except for some built-in shelves and some old pieces of furniture in need of repair. The room was covered in stains and the ceiling looked as if it might fall down at any moment. And one part of the floor had rotted away, leaving a hole.

  “I see. And who of those six was the—how do you call it—organizer of the trip?”

  “I told Leroux about the house—sorry, I mean Higashi. Because he was scheduled to become the new editor-in-chief—basically the leader of the club. But he also asked Matsu’ura for advice.”

  “So Higashi and Matsu’ura.”

  “Yes, that’s correct.”

  “Besides their own luggage, I saw they had food, blankets and other stuff with them. How did they arrange that?”

  “I helped with transporting the supplies my uncle had prepared for them. I had a fisherman’s boat help me bring the stuff to the island the day before the
ir arrival.”

  “Hmm, I shall need to check that out as a matter of routine, of course.”

  Rubbing his flabby cheek, the inspector turned his gaze upon the whole group once more.

  “Does anyone here have an idea what Matsu’ura’s motive could have been for committing these murders?”

  Voices started to murmur. Morisu joined the discussion too, but he was thinking of something else.

  A fair face.

  A fragile body that would break if hugged too strongly.

  Long black hair gliding down her neck.

  Thin eyebrows, always with an expression of embarrassment. Almond eyes, turned away in sadness.

  A small mouth with a little smile. A frail voice like that of a kitten.

  Chiori.

  Timidly avoiding the eyes of other people, the two of them had loved each other. Silently, but deeply.

  Oh, Chiori, Chiori, Chiori…

  He had not told anyone of this, not any member of the club, nor his friends, and neither had she. It was not because he was hiding it, nor was he embarrassed about it. It was simply because both of them were afraid. Afraid that the tiny cosmos they shared with each other would shatter if anyone knew about it.

  But all of it was suddenly crushed that fateful day. That night in January last year. It was evident that those six had robbed her of her life.

  If only I had been at Chiori’s side to the end…

  How often had he blamed himself, chastised himself. And how deeply he hated those six who had been there.

  He had lost his father, his mother and his little sister in the past in the same way. Without any warning, the selfish, cruel hands of unknown persons had taken the warmth that was his family away to a place he could never reach. And just when he had finally found someone to love in Chiori, that night had come.

  It was not an accident.

  She was not a girl to drink irresponsibly. She knew her heart was weak. Intoxicated and helpless, she was forced to carry on drinking.

  She was killed by them.

  She was killed.

  “Morisu,” asked Kawaminami from the adjacent seat.

  “Uh, yes?”

  “What about the letters?”

  “Hmm? What’s that?” Inspector Shimada asked when he heard what the two were talking about.

  “Actually, there’s something we forgot to tell you last time,” Kawaminami replied as he took the envelope with the letter out of his pocket. “This was delivered on the day the group went to the island. Morisu and I each got one.”

  “A letter from Nakamura Seiji?”

  “Y-yes.”

  “Both of you got one?”

  The inspector took the envelope from Kawaminami and checked the contents.

  “The exact same letter was delivered to the homes of all of the victims—including Matsu’ura,” he said.

  “Could it be related to what happened on the island?” asked Kawaminami.

  “I couldn’t really say,” replied the inspector. “But it might well have been just an unrelated prank. I mean, it was signed by a dead man.”

  Inspector Shimada gave a wry smile, showing his yellow teeth.

  Morisu joined in with a chuckle, but he was silently reaching back into his memories.

  2

  He had known that Nakamura Seiji was Chiori’s father even before she had told him. He had also heard that Seiji was living a somewhat peculiar life on a little island called Tsunojima off the coast of S— Town. More than six months had passed since losing Chiori, in which he spent his days as a half-invalid, filled with unrelenting sadness and anger. He was shocked when, one autumn day, he heard how Chiori’s parents living on Tsunojima had met their tragic death. He could not have imagined at the time that this case would help him release his own frustrated anger in the future.

  Confronting the six men and women who had driven Chiori to her death was constantly on his mind. But he would not be content with just accusing them, shouting in their faces that they had killed Chiori. He had been robbed of someone irreplaceable, someone he had needed in order to live. They had stolen her from him.

  The only thing he wanted was revenge. But he had only been able to channel his feeling into a concrete plan—for murder—when he learnt that his uncle, Tatsumi Masa’aki, had purchased the island of Tsunojima.

  The Blue Mansion on Tsunojima, where Chiori had been born. The tragedy with her parents. Six sinners who would go to the island just to satisfy their own curiosity. This mental image fuelled his urge to purge them, to paint a brand-new picture without the existence of those six.

  He had first thought about killing all six of them on Tsunojima and then dying there as well. But that would have meant burying himself among those sinners, as though he were one of them.

  He needed to pass judgement upon them. Revenge in the name of judgement.

  After long contemplation, he settled on a plan.

  A plan to kill all six of them on the island, but also a plan where he would stay safe and alive.

  He fired the first shot in early March, certain his prey would walk into his trap.

  “My uncle just bought Tsunojima. If you’d like to visit and stay in the Decagon House, I could ask him. How about it?”

  Naturally, they swallowed the bait.

  After it was all settled, he took responsibility for the preparations. He selected the days of their stay based on their schedules and the long-term weather forecast.

  For his plans to succeed, he absolutely needed days with clear weather and calm seas. Luckily, the forecast for late March didn’t show any bad weather. It was risky to bet on forecasts, but he could always just cancel the trip on the day itself if the conditions weren’t right.

  And so a one-week trip was agreed upon, starting on 26th March.

  He prepared bedding, food and other necessary supplies. He rented bedding for six persons. He was very careful to make the six think he was going to the island with them, while leaving the impression with everyone else that only six people were going and he wasn’t one of them.

  He wrote nine letters under the name Nakamura Seiji. The letters had two purposes.

  The first was naturally “accusation”. He wanted to let someone, anyone, know that those people had murdered a girl called Nakamura Chiori. As for their second purpose, the “letters from the dead” were the perfect bait to get Kawaminami Taka’aki moving.

  Sending one of those letters with Nakamura Seiji’s name to Nakamura Kōjirō had been a strategic move on his part, anticipating that Kawaminami would eventually pay him a visit. He knew Kawaminami very well. Receiving the letter, he would go sniffing around and finally turn to him, Morisu, for advice. Morisu was expecting him. Even if he had to contact Kawaminami himself, the strange letters going around would be the perfect excuse.

  He used a word processor, which was available for student use in a laboratory at the university, to type the letters. He also made two sets of the murder-announcement plates with materials he bought at a supermarket.

  On Tuesday, 25th March, the day before their departure, he posted the nine letters in O— City, went to S— Town and took the supplies over to the island in a fisherman’s boat he had reserved in advance. He then returned to S— Town, lied to his uncle that he was going to Kunisaki and borrowed his uncle’s car. In the boot, he had prepared a rubber dinghy with an outboard motor, a cylinder with compressed air, cans of petrol and other items.

  His uncle used the boat for fishing. He had secretly taken it out of the storage in the back of the garage, but as his uncle only used it in season, between summer and autumn, there was no fear of him finding out.

  Few people make their way to the other side of the J— Cape, even during the day. After hiding the boat and cylinder in some bushes near the shore, he
returned the car after enough time had passed. He lied about his plans once more to his uncle, saying he was going back to O— City that night and would go to Kunisaki again tomorrow. In truth he only went to O— City to get his motorbike and return to J— Cape in the middle of the night.

  It takes about ninety minutes for a car to travel from O— City to J— Cape in the afternoon. But you can make it in less than an hour if you go fast on a 250cc motorbike at night. And with an off-road bike, you can also cut across the empty fields and thickets next to the roads. He hid the bike in some woods near the shore, covering it with a brown sheet, so there was no need to fear someone would find it.

  Next, he set up the boat he had hidden and changed into a wetsuit. And so it was that, by the light of the moon and the unmanned J— Cape lighthouse, a lone figure made its way across the sea towards Tsunojima.

  The wind wasn’t strong, but it was terribly cold. The visibility was bad at night, too. He had borrowed the boat several times in the past and was used to handling it, but because of his bad state of health, the trip proved to be much harder than he had expected.

  As for why he was in a bad state of health, he had not drunk any water since the day before. His plan called for him to abstain from consuming water.

  It took about thirty minutes from J— Cape to Tsunojima.

  He landed on the rocky area. He needed to hide the boat here. He folded it up and used a rope to tie it into a bundle, together with the air cylinder and the outboard motor, which he had first wrapped in a waterproof cloth and then sealed inside a plastic bag. He then placed the package underwater between the rocks, where it would not be directly exposed to the waves, and weighed it down with a big stone. He also tied the package to a rock to stop it from floating away. Finally, he hid some reserve petrol cans among the rocks there, just as he had on the other side in the thickets of J— Cape.

  With a large torch hanging from his shoulder, he made his way beneath the moonlight to the Decagon House. He took the room to the left of the entrance—the room with water damage and no furniture—as his own. He slept in a sleeping bag he had brought there in the afternoon.