Su Ziqian was innocent and was merely a scapegoat. Hu Kexin's assistant was the real murderer.
After Hu Kexin's assistant committed the crime, she tore off the 'Script Room' label and replaced it and the 'Lounge' label which she had printed out in the same font.
Xu Weilai would only have to tear off the current 'Lounge' label to check if there were any tear marks left behind from the original 'Script Room' label in order to prove if her speculation was right.
The reason why Xu Weilai would suspect Hu Kexin's assistant was because Xu Weilai saw the surveillance footage of her sneaking into the printing room and heading towards the script room after she came out.
Xu Weilai had also verified with Hu Kexin's manager, who admitted that she had acted under Hu Kexin's orders. As they intended to humiliate Su Ziqian, they gave her the script and asked her to run through it with Hu Kexin. Hu Kexin's assistant was the one who printed the script.
