Mr. Tauf looked up, his face paling. "W-what is this about?"

Li Yun maintained his serious demeanor. "We have some questions for you. Please cooperate."

Mr. Tauf hesitated but ultimately stood up and followed them out of the staffroom. They led him to a private room where the interrogation would take place.

Meanwhile, Alex and Lisa approached Hunan Benit, who was sitting with a group of students in the courtyard.

"Hey, Hunan," Alex called out, trying to sound casual. "Can we talk for a minute?"

Hunan looked up, slightly surprised but nodded. "Sure, what's up?"

Lisa glanced around before speaking. "We heard that you and Rin Aina were close. We just wanted to know if you noticed anything unusual about her lately."

Hunan's expression grew somber. "Yeah, we were close. But she had been acting strange for the past few weeks, ever since... well, we broke up."

Alex leaned in, his tone gentle. "Did she mention anyone bothering her? Any teachers or students?"

Hunan hesitated. "She mentioned a teacher. She was scared of him but didn't want to say who. I thought she was just stressed out."

Lisa and Alex exchanged a look, knowing they were onto something significant.

In the principal's office, Kim Woojin and Si Xing confronted the principal.

"Principal, we need to discuss some discrepancies in the school's records," Kim Woojin said, holding up a file.

The principal frowned. "What discrepancies?"

Si Xing stepped forward. "We found evidence that suggests some students were receiving special treatment. We need to know why."

The principal's face flushed. "This is outrageous! I have always treated all my students fairly."

Kim Woojin remained calm. "We're not accusing you, but we need to get to the bottom of this. Who was in charge of the student welfare program?"

The principal hesitated. "Mr. Tauf. He volunteered to oversee it."

In the chemistry lab, Ayesha went through the records meticulously. She found a logbook detailing the borrowing of chemicals. Her eyes narrowed as she spotted an entry under Mr. Tauf's name, requesting a sedative two weeks ago.

"Gotcha," she whispered to herself, quickly taking a photo of the page for evidence. Of course the phone was given as her doctor's identity.

Back in the interrogation room, Li Yun sat across from Mr. Tauf while Su Mingji and Kim Jae-In stood behind him.

"Mr. Tauf, we need to know about your relationship with Rin Aina," Li Yun started, his eyes fixed on the teacher.

Mr. Tauf shifted uncomfortably. "She was just a student. I was trying to help her."

Kim Jae-In leaned forward. "Help her with what? We found her diary. She was scared of you."

Mr. Tauf's face drained of color. "I-I never meant to scare her. She was going to report me. I tried to stop her from ruining my career."

Li Yun's expression hardened. "So you drugged her and pushed her off the roof?"

Mr. Tauf's voice broke. "No! It wasn't like that! I didn't push her. She jumped... I tried to stop her, but she jumped."

Kim Jae-In shook his head. "The evidence suggests otherwise. You had access to the sedative found in her system. You were the last person seen with her."

Mr. Tauf's shoulders slumped in defeat. "I... I didn't want this to happen."

Later that evening, the team gathered in the investigation room, piecing together the final clues.

"Alex and Lisa found out that Rin Aina mentioned being scared of a teacher," Li Yun began. "Kim Woojin and Si Xing discovered that Mr. Tauf was in charge of the student welfare program and had access to sensitive information."

Ayesha held up the photo of the logbook. "I found records showing Mr. Tauf borrowed a sedative two weeks ago."

Lisa spoke up. "When Alex and I talked to Hunan Benit, he mentioned Rin Aina was scared of a teacher. He also said she helped a girl in distress. Maybe that girl knows something."

Alex added, "We need to find her. She might be the key to uncovering the whole truth."

Li Yun nodded. "Let's split up again. Alex and Lisa, continue looking for any students who might have been close to Rin Aina. Kim Woojin and Si Xing, follow up with the janitor and see if he can remember anything more about that suspicious woman. Ayesha and Kim Jae-In, let's dig deeper into the teachers' backgrounds."

Li Yun and Kim Jae-In headed to the staff records room. They began combing through the files, looking for any unusual behavior or complaints against the teachers.

"Look at this," Kim Jae-In said, pulling out a file. "Ms. Chen, the chemistry teacher, has had several complaints from students about her harsh treatment."

Li Yun glanced at the file. "Interesting, but we need more than that."

Meanwhile, Alex and Lisa were talking to a group of students in the courtyard. One girl, visibly nervous, finally spoke up.

"Rin Aina was helping me," she confessed. 

"She found out I was being bullied by Ms. Chen. Rin was going to expose her."

Alex's eyes widened. 

"Do you think Ms. Chen could have done something to Rin?"

The girl nodded, tears in her eyes. "Rin said she had evidence, Mr. Tauf...he is Ms.Chen's ex-husband. He had an affair with students in school and those students were..hic..tortured by Ms.Chen...I...I..was one...of them."

Alex who had never seen such a situation had truly opened his eyes today.

Even Lisa who had been on the front lines had a frown.

Lisa cleared her throat.

"Anyway, Do you know where Rin might have hidden that evidence?"

The girl cleaned her tears.

"Yes."

Alex and Lisa glanced at each other. It seems Li Yun was right, There was another story to the whole scene.

Back at the janitor's office, Si Xing and Kim Woojin pressed the janitor for more details.

"Try to remember," Si Xing urged. "What did the woman look like?"

The janitor, trembling, closed his eyes to recall. "She had a distinct smell... like chemicals. And she was wearing a lab coat."

Kim Woojin exchanged a look with Si Xing. "A lab coat? Who is this person now?"

With this new information, the team reconvened. Li Yun pieced together the clues.

"Rin Aina was helping a girl who was being bullied by Ms. Chen. She had evidence against her. The janitor saw a woman in a lab coat on the roof. Ms. Chen borrowed chemicals and had several complaints against her."

Ayesha nodded, her face serious.

 "And the sedative found in Rin Aina's system could have been from Ms. Chen's lab."

Kim Jae-In added, "Ms. Chen must have confronted Rin Aina on the roof, drugged her, and then pushed her off."

Li Yun stood up, determination in his eyes. 

"Let's bring Ms. Chen in for questioning."

They found Ms. Chen in the chemistry lab, seemingly engrossed in her work. Li Yun approached her calmly.

"Ms. Chen, we need to ask you some questions about Rin Aina," he said.

Ms. Chen looked up, her eyes narrowing. "What about her?"

"We have reason to believe you were the last person to see her alive," Li Yun stated.

Her face turned pale. "That's absurd! I had nothing to do with her death."

Li Yun held up the diary. "We found this in Rin Aina's locker. It mentions you and some evidence she was going to expose. Care to explain?"

Ms. Chen's hands shook as she tried to maintain her composure. "I... I don't know what you're talking about."

Ayesha stepped forward. "We also found traces of a sedative in her system. A sedative that matches what you borrowed from the lab."

Ms. Chen's facade crumbled. "Okay, I admit it. I confronted her. She was going to ruin my career! But I didn't push her. She tripped and fell."

Li Yun's voice was cold. "You drugged her, didn't you? You made sure she couldn't defend herself."

Ms. Chen broke down, sobbing. "Yes, I did. But I didn't mean for her to die!"

Li Yun didn't sympathize.

"You tortured young girls and even killed one, You are under arrest. Please cooperate."