Chapter 74

I explained how what Ms. Hasegawa had made would operate, presenting every piece of evidence I could.

"Since the dust was gone from the lid, the two of them must have been sitting on it. Ms. Hasegawa looped the rope around her neck, nearest me. Haruki stayed on the far side. Then, when Haruki opened the doorknob, the rope on the outside doorknob of the restroom would pull Ms. Hasegawa."

"......Is that even possible? If she had just hanged herself and could still be saved, Ms. Hasegawa wouldn't have any excuse."

"No, it's enough to make people believe that pulling the doorknob was what caused Ms. Hasegawa's death. I think she jumped off with all her might, using the toilet lid as a step. And while she was hanging, she probably kicked the wall hard to wake Haruki."

"S-so that's how it was!?"

After that I explained what Haruki had done.

"And then Haruki, the murderer...... originally, even back when the food-poisoning scare happened, she had been busy destroying evidence. She must have thought, 'This isn't my fault,' and started hiding the corpse."

"She dragged the girl out of the restroom, and like I just said, frantically erased the device, her own traces, and the leftover rope marks."

"Yes. Taking her outside also removed the dust. On top of that, she untied the rope and stretched it taut. She was terrified that the police would think it was a hanging, that the woman had died because she herself had pulled the rope, that she would be arrested for murder......"

"So in the end she made it look like Ms. Hasegawa had been killed by some random slasher. Haruki did."

"Yes. And it seems a drunk saw her leaving the park. After that she called the police. As a human being she probably couldn't just leave someone else dead like that."

I could at least acknowledge Haruki's final choice. If she hadn't reported it, I would have gone on believing I had killed Haruki myself.

Right about then, the fox-eyed one pretended to accept my reasoning and flipped the situation on its head.

"What if that was Haruki's goal all along?"

"Eh?"

"Isn't it possible Haruki kidnapped Ms. Hasegawa and made it look like this device was involved?"

"......Ah, is that all? Impossible."

"Why not......"

A sigh of exasperation. I countered the fox-eyed detective with a raised brow.

"Of course it is. How could Haruki kidnap anyone? Whatever the case, Ms. Hasegawa and Haruki had almost no contact. Ms. Hasegawa, on the other hand, could guess Haruki's leaving time from the department store's hours and, worst case, just wait in ambush. She could do it."

"Then again, maybe Haruki turned the tables on Ms. Hasegawa, who had the anesthetic, and used the device herself."

"Impossible!"

"Why not? Forget the anesthetic! She could have knocked Ms. Hasegawa out and put her to sleep!"

Here I used information I'd gotten from Detective Akaba.

"That's wrong! The cause of Ms. Hasegawa's death was apparently strangulation in a single blow. And there were no signs she'd struggled against a rope. A single blow means no anesthetic was found in her body either, right?"

"Ugh!? B-but...... is that really true? Did Haruki really intend to do it?"

One last struggle for the fox-eyed one. I was just about to present the decisive evidence when Detective Akaba came walking toward us from inside the department store.

When I nodded, she reported what she'd found.

"I found it. On a security camera by the first-floor restroom. There's Ms. Hasegawa slipping the 'Cleaning in Progress' sign into her backpack! When she came in the backpack was small, but when she left it was bulging—no doubt about it!"

"Eh? What does that prove!? A backpack at the scene...... the sign...... Ah!?"

The fox-eyed detective was caught off-guard by Detective Akaba's ambush. Let me spell it out.

"I think Ms. Hasegawa took the backpack home. The security cameras show the department store was still open; Haruki was still on shift. And the sign—she needed it. If someone else came in while she was setting up the device, the plan would fail. She used the sign to keep people out of the restroom."

"That sign...... no way!?"

The fox-eyed one was floored by the sign she herself had overlooked. This was the end.

"This proves Ms. Hasegawa's reasoning! When Haruki left the restroom she must have kicked this sign aside in a panic and forgotten to dispose of it. The police thought it had been left as a prank...... But I—and Detective Akaba—focused on it and uncovered the truth! Do you accept it now!?"

The fox-eyed one pressed a hand to her face and began to laugh—"kukuku." Then, leaning against the wall, she exploded in anger.

"A mere detective...... to the police! To the police......!"

Detective Akaba took several steps back. She seemed mortified that the full force of the police had been outdone......

Yeah. I got carried away. I fought as a detective. I really do hate myself for it.

I had gone too far to find the truth. So, filled with regret—and intent—I spoke.

"Please don't use any of this reasoning."

"Ah!?"

That remark left even the fox-eyed one gaping; Detective Akaba stared in shock. Maybe it was only natural. In mysteries, detectives solve riddles and make the police move. Almost none say, "Forget what I just told you," after openly describing their reasoning and embarrassing the police.

"Therefore, Haruki committed no murder. Just understand that, and forget everything else. Don't tell anyone...... Please keep this between us, Detective Akaba."

Detective Akaba let out a "Hah." The fox-eyed detective's eyes widened, regarding me with suspicion.

"So you're not trying to stand out or to make the police look foolish......?"

"......I never thought about that."

The fox-eyed detective finally accepted my words in their true sense. As proof she said this:

"All right. I won't rely on your reasoning. I'll forget it."

"Please...... I couldn't do anything—I'm an idiot. A fool like me who couldn't stop such a sad case—please forget my reasoning."

Detective Akaba was the one who now looked at me in utter bewilderment.

"Wh-what's wrong? You suddenly look so down......"

We'd arranged it when she first contacted me. I thanked her for preparing the evidence, then added something important.

"No, it's fine. Thank you so much for today...... Oh, right. Please keep this a secret especially from Detective Chikage."