Detective star season 6 case 4 who is the murderer?

In the fourth case of Star Detective Season 6, Sky Apartment, the killer of Zhen model is Sa Fashion.

Because Zhen Model discovered that Sa Fashion had stolen the spare key stored in the property by Fang Jie, the first victim of Sky Apartment, through the pinhole camera installed in the property, Zhen Model decided that Sa Fashion was the murderer of Fang Jie, and Sa discovered the video secretly recorded by Zhen Model. In order not to expose her killing behavior, Sa Fashion killed Zhen model.