Maybe someone was waiting for her to get home. People that live in apartments tend to park in the same spot. It may not have been totally random.
I don't have a very good understanding of social media apps and those that share your location.... But it has been mentioned that Aniah may have had them on her phone so her "friends" could see where she was at any given moment.
Is it possible that this "Eric" fella was on her friends list- by her choice- and so her location was visible to him?
Perhaps she did decide to just go home after dropping off her brother and buying the chips and thru one of her apps let this eric know that. Maybe eric wasn't very happy about that and could see where she was and found her either at the station or her apartment?
Or if her location wasn't visible to him, perhaps he simply googled her or did some asking around and found out where she lived and was there waiting at the apartments for her to return. Maybe she had let him know earlier on that she was probably gonna be too tired to get together.
Or- maybe because she was too tired to go out and he was "eager" to meet her, and she being a super kind girl compromised and agreed to meet at the gas station, thinking she would be safe there, and thinking she could just say hello and agree when they would get together next. Her behavior inside the store may have seemed "off" according to her dad and the ex-fbi guy because she had a bad feeling about "eric" and because she was tired.
She even could have agreed to meet at the station and leave from there to go out, but decided it was a bad idea after meeting him and maybe she tried telling him she was gonna go home after going in the store and her behavior in the video would reflect the burden of that emotion.
Once outside the store, either he was waiting in her car or followed her home.
Or, this is a stretch, maybe "eric" wasn't eric after all but coincidentally really a fellow student who she knew (or at least knew her) posing as Eric- so this guy easily found out where she lived and was in the parking lot when she got home.
Praying for answers and peace for her family, this pain is unfathomable.