I know they said driver cleared, but who else could it be? Why would anyone get dropped off in park in the middle of the night? If she was meeting someone then she could have been dropped off at her place and driven her car or they could have swung by her place to pick her up. Unless it’s a married guy who doesn’t want anyone to recognize him!? At that time of night, no cars out - so if any were then a residence/ business video camera will have picked them up and LE / FBI will get the person. There has to be an electronic trail to set up this meeting! If not, then driver involved!