Who's the fourth murder in Star Detective Season 6?

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

Sa Fashion was cheated by Fang Jie real estate. After being cheated of 6 million yuan, Fang Jie lost contact. Later, Sa Fashion found that Fang Jie lived in the aerial apartment where she worked, so Sa stole Fang Jie's spare key in the property, went to Fang Jie's room to defend her rights, and killed Fang Jie by mistake. Zhen model discovered that Lisa had stolen the key through the pinhole camera installed in the house, and knew that Lisa was the murderer of Fang Jie. Later, it was discovered by Lisa. In order not to expose his purpose of killing, he chose to kill Zhen model.