After class, Jina and I met in the library to discuss the mystery of the costume.

While we were discussing it, Jina informed me that she hadn't talked to Jiro yet.

"So it's not him..." I said. "I had a thought that someone returned the costume after you talked to them."

I could see the undisguised curiosity mixed with impatience in Jina's eyes as she sat across from me. Like me, she was eager to solve this mystery.

"Really?" Jina asked. "So you think someone felt guilty or threatened after I talked to them and that's why they returned the costume?"

"I don't know their reason for returning the costume, but yes, I think maybe they got scared after you talked to them and returned it."

"Then why did they steal the costume in the first place?" she asked. "Only to return it so easily after a simple conversation, when I had no proof or evidence?"

"I..." I paused. "I don't know..."

She was silent.

"Ah..." I sighed. "I'm more interested in who did it."

"Are you sure the costume was returned today? Maybe it came back yesterday and you just didn't see it?" Jina asked.

"Yes, I'm sure the costume was returned today," I replied. "We checked the storage room before leaving school yesterday and it wasn't there."

"Got it..."

Jina thought for a moment, lowering her eyes.

"I'm starting to think we're having a mass hallucination," I said.

"Nah... not a hallucination," she muttered, still thinking.

"Do you think it was a prank?"

"No, I don't think so... That would be a really stupid prank..."

"Who knows? People do stupid things sometimes."

"I'm just..." she paused. "...not quite sure of the motive... but... maybe it was jealousy... or..."

She fell silent without finishing her thought...

But there was something strange in her silence, I noticed something in her eyes...

"Wait..." I said, realizing she had something on her mind. "It sounds like you've figured something out?"

She raised her eyes to me.

"Well... I might have an idea who the culprit might be..." she said with a slightly uncertain voice.

She has a hunch and still hasn't said anything?!

"Really?! Tell me!" I shouted excitedly.

"Calm down, it's just speculation and I have no proof..."

"I still want to hear it!"

"Okay, okay, just calm down... I was going to share my thoughts with you anyway... So, as you know, there are two main questions: who did it and why... On the question of who did it, I have an idea, although again, it's just a guess. But for the question why, I don't have a clear answer..."

Jina fell silent again, thinking.

Unable to bear the silence, I said, "Why don't you tell me your idea already? Don't torture me!"

"Well... Okay..." she paused. "I think the culprits were Rina and Ken..."