Zhang Mengyao's body was found inside the Experimental Primary School, which is where he worked.
Not to mention why the murderer did this, just the fact that the murderer was able to place the sculpture inside the Experimental Primary School indicates that the perpetrator must be quite familiar with the Experimental Primary School.
Analyzing from this clue, there is a very high possibility that the perpetrator works at the Experimental Primary School.
So, when Zhang Mengyao left the school back then, who else left with him?
From the investigation of Zhang Mengyao's residence, it seems that there is no possibility he returned home alone.
Either he didn't return home, or if he did, he took a car through the underground parking garage.
