A Ghost

The cleaner auntie? Xiao Rui frowned. "Was she a fair and fat woman who had her hair in a bun?"

Qiao Qing shook and then nodded her head. "I can't really remember but I suppose so."

"That should be Auntie Qin. Now that I think about it, she is indeed suspicious. We have come across her way too often in this case."

When they first arrived at 22 High School, Auntie Qin was cleaning the corridor. When questioned, Jia Han also told the police that it was Auntie Qin who suggested him to sneak the medicine into the milk teas.

At the time, Xiao Rui merely thought this was a kind cleaning lady who cared about the students. She was only giving suggestions out of good intentions. But with Qiao Qing's testimony, things didn't seem so simple anymore. If Auntie Qin was the murderer, then she would know about the poison on the straws and the resealed traces on the packaging. It would explain why she was so quick to pick up the packaging Wei Lan dropped.