What I think happened

This is what I think happened:
On the last episode when the four girls and Mona open the トランク of the police car (Which was previously pushed in a lake) they gasped to the sight of something shocking. What I assume is it was a body. Now I have a couple ideas of who's body it could be in that trunk. Let's see, who's been going missing in this season,

Jason-after Jason survived the elevator accident he was put in the hospital. but when the girls went out for a second, just a few 分 later a nurse reported that Jason was missing from his hospital ベッド (This happened in 3x19).

Jason could have been unconscious in the トランク of Wilden’s police car when Hanna and Aria pushed it in the lake (They really should have thought of checking the トランク first).

Cece- We all saw Wilden roughly push Cece in the cop car. Maybe Wilden’s a bad cop and put her in the トランク at some point. That または he shot Cece and hid her in his トランク until he could find out what to do with the body.