“What the hell is this...?”
Kuruma, standing next to him, was struck speechless. Yuma staggered into the First room as if drawn in, approaching Kozushima's body.
Looking down at him with heavy breaths, Yuma fell even deeper into confusion. A piece of A4 paper had been left on top of Kozushima's body, pinned to his chest by the knife.
“What is this...?”
The hoarse voice came from him unbidden. On the paper were dozens of dark red stick figures and a few English letters. His vision was distorted, creating the illusion that the figures on the paper were dancing.
“Another mysterious message in blood. Well, this one is in pictures, not words. But somehow, it seems familiar, doesn't it?”
Tsukiyo gave Yuma a testing sidelong look.
“...The Dancing Men.”
Yuma spoke, and Tsukiyo declared “As expected of you, Yuma!”
The Adventure of the Dancing Men is a short story included in The Return of Sherlock Holmes, published in 1905. It depicts Sherlock Holmes's attempts to solve a code consisting of childlike images of stick figures. The code written on the paper pinned to Kozushima's chest was very similar.
“But in the code of the Dancing Men, there were many different figures present. There are far fewer unique figures here.”
Tsukiyo spoke softly, placing her hand on her chin.
“Never mind the code! What's going on here!? Why is there a knife in Mr. Kozushima's chest!? He was supposed to have been poisoned!”
“Well, someone must have stabbed the body.”
“Why would they do that!? And more importantly, this was supposed to be a locked room. How did they get in!? And why leave a code!?”
“Don't yell at me. I'm surprised too, but give me a moment to think. In the meantime, can you take a picture of the code? And then I'll leave the autopsy to you.”
Tsukiyo shook her head, then crouched down and began examining Kozushima's body. Yuma had no choice but to take out his smartphone and take a picture of the code over her shoulder, as instructed. Then he joined her in examining the body of Kozushima, who lay on the floor with his mouth half open. When Yuma tried to move his arm, he felt a slight resistance from his stiff joints. The knife was stuck up to the handle in the dead center of his chest, almost certainly lodged in his heart.
As he examined the body, Yuma heard Tsukiyo rambling to his side.
“That knife is from the Kozushima Collection. It was used in Knives Out. I love the detective in that movie. He was played by Daniel Craig, you know? I never imagined I would ever see 007 in the role of a great detective. I bought the blu-ray the day it was released-”
“Ms. Aoi, focus!”
Yuma snapped at her, and Tsukiyo started.
“Oh, sorry. There isn't much blood loss. That's a relief. If he'd bled a lot, the code might have been rendered illegible.”
Tsukiyo scratched at the tip of her nose and fell into deep thought.
“Have you realized something?”
“Don't rush me. I'm currently considering whether what I'm thinking is compatible with my other hypotheses.”
Tsukiyo closed her eyes and began to talk to herself.
“Why did you stab the dead body? Did your grudge run that deep? Was poisoning him just not enough? Or did you want to draw attention to the code? But why did you need to leave a code now in the first place? And how did you get into this room...?”
Tsukiyo raised her eyes and approached the door, releasing a puff of white air. Standing next to the still-dazed Kuruma, she began to examine the door.
“As I thought, there are no signs of the door being forced, and no signs of any sort of physical tricks with thread. That means...”
Tsukiyo approached the First key where it still lay on the carpet and picked it up. Her eyes shot open.
“Yuma, look.”
Yuma went over to Tsukiyo as she beckoned him over and looked at the floor where Tsukiyo was pointing. There was a small amount of white dust on the black carpet under the key.
“What's that?”
Yuma asked, but Tsukiyo just silently took out her smartphone and took a video of the area around the floor, talking to herself.
It was probably best not to interrupt her. As Yuma watched, the corners of Tsukiyo's mouth slowly turned upwards. Then, her eyes opened wide.
“I see, I see, I see. This is interesting. This is supremely interesting!”
Suddenly, with steps light as a ballerina's, she returned to Yuma's side.
“Yuma, this is amazing. This is the greatest trick I've ever seen in my life. It's rare to see such a beautifully executed crime. I'm truly grateful I was able to be here to see it first-hand.”
As Yuma stood there overwhelmed by her strange behavior, Tsukiyo grabbed both of his shoulders.
“Could it be... You've figured out who the culprit is?”
Yuma asked nervously, and Tsukiyo spread her arms wide and threw her head back.
“Of course. I already have all the clues I need to solve this tragic yet beautiful case. From them, it is possible to employ deduction to narrow down the possibilities to only the truth.”
Tsukiyo spoke loudly, looking directly into Yuma's eyes and smiling mischievously like a child.
“If this was a honkaku mystery novel, this would be the part where 'that' goes. This is a rare opportunity, so I'll take it to make an announcement.”
Tsukiyo brushed her hair back with great affectation, then made a theatrical announcement:
“A challenge to the reader. All of the information necessary for you to deduce the truth behind The Glass House Murders has been revealed. I wish for you to be the one to uncover who the culprit is and how they carried out this mysterious crime. This is my challenge to you. I wish you good deductions, and good luck.”